Cool , that current sensor you use is pretty small do you have it laid down on a pcb/breadboard? Or just floating somewhere?

LOS limit would be cool, maybe also mAh limit...

Originally Posted by Dennis Frie

Year, but only twice as tall compared to the use of 8 lines instead of 16
The width of the letters (or the width of 8 bit) is defined by the clock-rate and SPI-settings. The height is only defined by the lines. If you use single line (only even or odd) the height of 1 "pixel" will result in a "long" pixel. Using 2 lines as height and max SPI speed seem to give an pretty good pixel-form

Excellent! This puzzle is coming together, piece by piece..

Originally Posted by msev

Cool , that current sensor you use is pretty small do you have it laid down on a pcb/breadboard? Or just floating somewhere?

LOS limit would be cool, maybe also mAh limit...

The current-sensor I use at the moment is taped and soldered to a little pcb with a small capacitor at Vin and a lowpass filter on the output.

I think it's pictured somewhere with a bunch of red tape around it

By request from user...

This is the schematic and the components I use at the moment. Works great for now.
Next time I buy components, I will order a couple of zener-diodes and a 10K pot. But for now, this is what I use. I get a very good sync with HK camera and fatshark (not tested with other cameras).


Components used:
1 x Atmega.
For an "easy and small hardware solution" I can recommend Arduino Pro mini (16 mhz)
http://www.sparkfun.com/products/9218

Arduino nano from dealextreme should be great as well, but I haven't received the board yet.
http://www.dealextreme.com/p/arduino-nano-v3-0-81877

Other Arduino boards can be used as well, but those mentioned have a nice size
Please note, you need AIN0, AIN1 and RX/TX. For some reason AIN0/AIN1 (can't remember which one) is not breaked out on the Arduino Mega (1280) board, and maybe other boards as well. Please check

Resistors:
2 x 120 ohm
1 x 10K ohm
1 x 100K ohm

Variable resistors:
1 x 50K pot

Diodes:
3 x 4148

Capacitors:
1 x 0.1 uF

As mentioned above, I would probably change a few components if I had the components laying around. But as I get a perfect sync I haven't really been bothered to order new components.

GPS:
http://flytron.com/osd-headtrackers/...ps-module.html

On current-sensor a 0.1 uF capacitor is added on Vin. A little lowpass filter is added on the output to average the pulses from the switching.

Finally got my Arduino nano from DE, works perfectly. Haven't tested the GPS yet..



Anyone know the name of this connector?

Originally Posted by andreas77

Finally got my Arduino nano from DE, works perfectly. Haven't tested the GPS yet..

Very nice

Originally Posted by andreas77

Finally got my Arduino nano from DE, works perfectly. Haven't tested the GPS yet..



Anyone know the name of this connector?

That looks like a 6-pin micro JST.
You just need to be carefull with the pin spacing as the micro JST have differnet pin spacing. 1.5, 1.25, 1.0 , ...
And the plug changes slightly from size to, judging by the ones I have for the FPV cams that looks like the smallest pin spacing 1.0.

It looks simillar to this one: http://cgi.ebay.com/Mini-Micro-JST-1...item2a128ea873

If you don't have the cennoctor, I would just change it with another one. I only think you need 4 wires Vin, ground, TX and RX.

Originally Posted by IceWind

That looks like a 6-pin micro JST.
You just need to be carefull with the pin spacing as the micro JST have differnet pin spacing. 1.5, 1.25, 1.0 , ...
And the plug changes slightly from size to, judging by the ones I have for the FPV cams that looks like the smallest pin spacing 1.0.

It looks simillar to this one: http://cgi.ebay.com/Mini-Micro-JST-1...item2a128ea873

Thanks! You are right, looks like 1.0 pin spacing.

Originally Posted by Dennis Frie

If you don't have the cennoctor, I would just change it with another one. I only think you need 4 wires Vin, ground, TX and RX.

Yep, that will do it also. I have wired it up to the OSD now, but it's not working, I guess I need to change a few things. When I power it up, the OSD works for a few seconds, then the text gets garbled and the OSD crashes.

Things I've tried so far:
- Changed the baud rate to 4800
- Removed GPS configuration code for 5Hz update rate & 2 gps-strings

One more thing. The GPS uses 2.7v TTL levels, I've read somewhere that you could just put a 1k resistor i series on the GPS rx input and it should work fine. Do you agree with this or do I need to do something more?

Anyway, I'll keep trying to find the problem, but help is appreciated.

/Andreas

Originally Posted by andreas77

Finally got my Arduino nano from DE, works perfectly. Haven't tested the GPS yet..



Anyone know the name of this connector?

what is that u mounted ur nano on?

Originally Posted by ferdous7466

what is that u mounted ur nano on?

It's a prototype board with the circuit for the OSD.

Anyone succeed with 4800bps GPS? For me 4800bps kills the video, just 9600bps works.

Ok, I think I found the problem. For 4800 baud, you need to:

- Change Serial.begin(9600); to Serial.begin(4800);
- Change UBRR0L = 103; to UBRR0L = 207;

At least the OSD doesn't crash anymore and the time is displayed, so I guess it's communicating with the GPS now? It haven't found any sats yet, but it sits on my desk inside and have just traveled half-way around the world, so I guess it will take some time.

Originally Posted by andreas77

Ok, I think I found the problem. For 4800 baud, you need to:

- Change Serial.begin(9600); to Serial.begin(4800);
- Change UBRR0L = 103; to UBRR0L = 207;

At least the OSD doesn't crash anymore and the time is displayed, so I guess it's communicating with the GPS now? It haven't found any sats yet, but it sits on my desk inside and have just traveled half-way around the world, so I guess it will take some time.

Thanks It works, I missed UBRR0L, but why there is Serial.begin(9600); AND UBRR0L = 103;. Boud rate is set two times?

Originally Posted by evvaldis

Thanks It works, I missed UBRR0L, but why there is Serial.begin(9600); AND UBRR0L = 103;. Boud rate is set two times?

I prefer not to use Arduino-code (it's a bit slow) so the serial-communication was originally setup without Serial.begin etc.
When I had to set the GPS update rate to 5 hz I just quickly tested with Serial.begin and Serial.print(). Guess I haven't done the rest of my work (forgot to replace it with none-arduino code)
The serial.print and serial.begin command is only used in the startup, so it doesn't really matter what you use here.

You can't use Serial.print in the main code or interrupt. Feel free to give it a try

Originally Posted by andreas77

Ok, I think I found the problem. For 4800 baud, you need to:

- Change Serial.begin(9600); to Serial.begin(4800);
- Change UBRR0L = 103; to UBRR0L = 207;

At least the OSD doesn't crash anymore and the time is displayed, so I guess it's communicating with the GPS now? It haven't found any sats yet, but it sits on my desk inside and have just traveled half-way around the world, so I guess it will take some time.

If it shows the time right it receives info from GPS - and have found and "analyzed" the correct NMEA-string used for speed, position etc - so you should be good
But you will have to check the latitude and longitude info - it's not necessarily the same format as the MKT gps.
Altitude and number of satellites is read from another NMEA-string.

Please note, speed and altitude will show as soon as the GPS send usefull info. LOS will not show before home-position has been set. The home position will automatically be set when the GPS gets GPS-fix - but with a delay. The delay is defined as 25 or 50 updates (can't remember). This will make the OSD wait until it gets GPS fix, wait another 5-10 seconds (with 5 hz GPS update rate) to get a more accurate position and then automatically set the home position. When LOS changes from "....." to "00" - the homeposition have been set.

I installed the OSD quickly yesterday on a flying wing, but noticed a decrease in RC-range on ground test.
I don't have time to do further tests before I get home from holiday - but please remember to do a range test before flight.

A shame, the OSD would have been usefull for the flight this evening

Beautiful pics,...what a shame that its reducing range,...can you pinpoint or eliminate the reason? what is the separation between your osd and the rc receiver?

Not alone. Both my Dragon OSD's give out a surprising amount of RF. Reduces range by about 50% when in close proximity to rx. A couple of foot separation makes a huge difference to that it you have the room in the plane.

Originally Posted by Dennis Frie

If it shows the time right it receives info from GPS - and have found and "analyzed" the correct NMEA-string used for speed, position etc - so you should be good
But you will have to check the latitude and longitude info - it's not necessarily the same format as the MKT gps.
Altitude and number of satellites is read from another NMEA-string.

Please note, speed and altitude will show as soon as the GPS send usefull info. LOS will not show before home-position has been set. The home position will automatically be set when the GPS gets GPS-fix - but with a delay. The delay is defined as 25 or 50 updates (can't remember). This will make the OSD wait until it gets GPS fix, wait another 5-10 seconds (with 5 hz GPS update rate) to get a more accurate position and then automatically set the home position. When LOS changes from "....." to "00" - the homeposition have been set.

I installed the OSD quickly yesterday on a flying wing, but noticed a decrease in RC-range on ground test.
Want have time to do further tests before I get home from holiday - but please remember to do a range test before flight.

A shame, the OSD would have been usefull for the flight this evening

Thanks for the explanation. I think everything is working, after a while it picket up 7 sats and it shows speed, altitude and LOS, so I should be good, right? So far I'm pretty happy with this GPS. I only did a few short tests, but it gets a sat lock pretty fast (a few seconds after hot start), even inside my appartment with a 1.3GHz vTx close by. The only drawback I've found so far, is that it only seems to support 1Hz update rate.

I don't know much about RF, but could it be interference from the 16MHz crystal? Second harmonics of 16MHz = 32Mhz = pretty close to your 35MHz RC-link.

Beautiful pictures, btw!

I'm gonna use 2.4ghz at first for the rc link and about 50cm of separation so i hope i'll avoid interferance.. You bought that 21$ em411 from dealextreme right?

Originally Posted by msev

Beautiful pics,...what a shame that its reducing range,...can you pinpoint or eliminate the reason? what is the separation between your osd and the rc receiver?

Separation is always a good idea - but I will definitely try to pinpoint it. RF noise is not okay, need to be eliminated
The range reduction only occurs when the SPI blasts out pixel. The Arduino itself (16 mhz crystal) is tested alone without any reduction in range. A separate power supply has also been tested. A totally "clean" code that only shows a line also makes the same problem. I have to make a breadboard version and pinpoint the exact reason, but don't have the time right now.

Originally Posted by andreas77

Thanks for the explanation. I think everything is working, after a while it picket up 7 sats and it shows speed, altitude and LOS, so I should be good, right? So far I'm pretty happy with this GPS. I only did a few short tests, but it gets a sat lock pretty fast (a few seconds after hot start), even inside my appartment with a 1.3GHz vTx close by. The only drawback I've found so far, is that it only seems to support 1Hz update rate.

I don't know much about RF, but could it be interference from the 16MHz crystal? Second harmonics of 16MHz = 32Mhz = pretty close to your 35MHz RC-link.

Beautiful pictures, btw!

If you use 1 hz update rate, please see line 2264;
if (homeposcount > 50) {

If you change 50 to 5 it will set homeposition 5 sec after GPS-fix (with 1 hz update rate).

Originally Posted by msev

I'm gonna use 2.4ghz at first for the rc link and about 50cm of separation so i hope i'll avoid interferance.. You bought that 21$ em411 from dealextreme right?

Yes, this one.

Originally Posted by Dennis Frie

If you use 1 hz update rate, please see line 2264;
if (homeposcount > 50) {

If you change 50 to 5 it will set homeposition 5 sec after GPS-fix (with 1 hz update rate).

Thanks!

Another thing that crossed my mind.. Have you looked into the possibility of using your firmware on the SimpleOSD XL? Do you think it would be possible without major changes?

Originally Posted by andreas77

Thanks!

Another thing that crossed my mind.. Have you looked into the possibility of using your firmware on the SimpleOSD XL? Do you think it would be possible without major changes?

Or the OpenSourceLRS by flytron, would love to throw this in on a Rx??

Originally Posted by andreas77

It's a prototype board with the circuit for the OSD.

do u have detail on that board. the board and photos?

Originally Posted by ferdous7466

do u have detail on that board. the board and photos?

Check page 1

Originally Posted by andreas77

Thanks!

Another thing that crossed my mind.. Have you looked into the possibility of using your firmware on the SimpleOSD XL? Do you think it would be possible without major changes?

I guess that's possible if you can upload custom firmware. If it's the same guys who have made OpenLRS I guess they don't mind if we use custom firmware
But I haven't looked more at it.

Originally Posted by andreas77

Thanks!

Another thing that crossed my mind.. Have you looked into the possibility of using your firmware on the SimpleOSD XL? Do you think it would be possible without major changes?

Ok, I've looked into it a bit myself, and my first impression is that it looks doable, but it will require some changes in the code. The main difference is that SimpleOSD uses a LM1881 video sync separator that generates line and frame sync pulses to the atmega.

Here's what I've found out so far: (I might have made errors!)
- Line sync => PD2/INT0
- Frame sync => PD3/INT1
- MOSI => Pixel generation
- Current sensor bat 1 => PC4/ADC4
- Current sensor bat 2 => PC3/ADC3
- Voltage bat 1 => ADC7 (using 1/10 voltage divider?) (Not sure about this one)
- Voltage bat 2 => PC2/ADC2 (using 1/10 voltage divider?)
- RSSI => PC1/ADC1
- AN1 => PC0/ADC0
- Push button => PD6
- PD5 => Red LED
- PB2 => Audio out
- Video signal is also connected to PC5/ADC5, I wonder what this is used for?
- 14.745MHz system clock (why that odd number?)

Next question is if the bootloader it uses works with the Arduino IDE? And is really worth the effort? SimpleOSD firmware works just fine as it is..

Originally Posted by andreas77

Ok, I've looked into it a bit myself, and my first impression is that it looks doable, but it will require some changes in the code. The main difference is that SimpleOSD uses a LM1881 video sync separator that generates line and frame sync pulses to the atmega.

Here's what I've found out so far: (I might have made errors!)
- Line sync => PD2/INT0
- Frame sync => PD3/INT1
- MOSI => Pixel generation
- Current sensor bat 1 => PC4/ADC4
- Current sensor bat 2 => PC3/ADC3
- Voltage bat 1 => ADC7 (using 1/10 voltage divider?) (Not sure about this one)
- Voltage bat 2 => PC2/ADC2 (using 1/10 voltage divider?)
- RSSI => PC1/ADC1
- AN1 => PC0/ADC0
- Push button => PD6
- PD5 => Red LED
- PB2 => Audio out
- Video signal is also connected to PC5/ADC5, I wonder what this is used for?
- 14.745MHz system clock (why that odd number?)

Next question is if the bootloader it uses works with the Arduino IDE? And is really worth the effort? SimpleOSD firmware works just fine as it is..

Great info, thanks
I will probably continue to use Arduino mini/nano - as a DIY project it's fun to make some hardware as well.

But with that said, I'm i bit tempted to test it.
The code is easily changed to support SimpleOSD. Replace the analog comparator interrupt with the "new line" interrupt and just make a simple "new frame" interrupt that resets line-count. Shouldn't take long

Edit; just mailed flytron to be sure it's okay to use custom firmware

Originally Posted by Dennis Frie

Great info, thanks
I will probably continue to use Arduino mini/nano - as a DIY project it's more fun to make some hardware yourself as well. And yes, why bother if the software on SimpleOSD already works great

But with that said, I'm i bit tempted to test it
The code is easily changed to support SimpleOSD. Replace the analog comparator interrupt with the "new line" interrupt just make a simple "new frame" interrupts that resets line-count. Shouldn't take long

Just be careful, I think I just bricked mine.. The bootloader used is called Megaload, I've successfully uploaded a simple "pin toggle" program, but now the bootloader seems to be broken, can't upload code anymore.. This happened after I added a line to the code the clear the watchdog-timer (which is enabled).

Originally Posted by Dennis Frie

Edit; just mailed flytron to be sure it's okay to use custom firmware - but they seem to like open-source

I've read on their forum that they are planning to release the source code for it, so I guess it's ok.

Originally Posted by andreas77

Just be careful, I think I just bricked mine.. The bootloader used is called Megaload, I've successfully uploaded a simple "pin toggle" program, but now the bootloader seems to be broken, can't upload code anymore.. This happened after I added a line to the code the clear the watchdog-timer (which is enabled).

Hmm, sounds weird.. The bootloader should always run the first second or so. You can't upload a new bootloader with an ISP (if the pins are available)?

Originally Posted by Dennis Frie

Hmm, sounds weird.. The bootloader should always run the first second or so. You can't upload a new bootloader with an ISP (if the pins are available)?

Never mind, I was doing it the wrong way.

Lessons learned:
- Set megaload baud rate = 38400
- Remove all cables from simpleosd
- Connect serial cable and battery while pressing the button.
- Be sure not to touch anything else on the board (like the crystal) while pressing the button.

Now I have another problem, arduino's delay() routine runs ~4.5x too fast. AVR Libc routine _delay_ms() works perfect. I've defined a new board in board.txt where I set f_cpu to 14745000L, also defined F_CPU in my source code..

Any ideas?

Just talked to Melih from Flytron. The SimpleOSD seems to be a good priced finish hardware solution for this project. (You can order SimpleOSD replacement if you already have a USB -> serial converter etc)
http://flytron.com/osd-headtrackers/...osd-xl-v2.html

When I get back from holiday and have received the SimpleOSD I will make a code-version compatible with SimpleOSD

Andreas77 - Sorry, can't help you with the delays. 4.5x faster sound like a weird number

What the advantage of the SimpleOSD?
Having more pins exposed?

Originally Posted by IceWind

What the advantage of the SimpleOSD?
Having more pins exposed?

It's the same microcontroller, it shows the text the same way etc. so you should be able to do exactly the same with SimpleOSD and the hardware shown in this thread.

The only major difference is, that SimpleOSD uses a sync-seperator instead of the analog comparator.

So, it's basically a good and pretty cheap hardware solution if you don't want to make it yourself. I think it's fun to make myself - but if I need an OSD or maybe two more, I don't mind to pay a little extra for a complete hardware solution with all SMD components

Ahhh I haven't noticed it had the sync-separator.
I have some at home (LM1881) but I do prefer the ultra-simple solution like the one you've been developing. Well depending on the planned usage.
Of course it ends up having limitations but again, it's a super easy solution with a minimal parts counts
The less I have done was (ATmega88 + resistor).

Except for the few pins exposed the e-osd from HK is also a great hardware for this, I was actually planning to go for it and upgrade it's firmware.
I may had some extra wires for GPS and for a current sensor.

Originally Posted by IceWind

Ahhh I haven't noticed it had the sync-separator.
I have some at home (LM1881) but I do prefer the ultra-simple solution like the one you've been developing. Well depending on the planned usage.
Of course it ends up having limitations but again, it's a super easy solution with a minimal parts counts
The less I have done was (ATmega88 + resistor).

Except for the few pins exposed the e-osd from HK is also a great hardware for this, I was actually planning to go for it and upgrade it's firmware.
I may had some extra wires for GPS and for a current sensor.

Year, the Arduino and the analog comparator with a few components is pretty simple and works perfect. For a DIY project I also prefer the analog comparator rather than the LM1881.

No worries, I will continue with the Arduino OSD, but I will also make the few changes needed to make it compatible with SimpleOSD. Hopefully I can make the same code work on both Arduino and SimpleOSD, so you can just outcomment 2-3 lines to choose the Arduino version or SimpleOSD.

The e-osd would have been perfect if it had RX breaked out - and preferable a bit more memory.

I'm going to Zermatt in a couple of hours and will be away for 2 weeks. Hopefully I will be able to get a couple of flights and get some ground recordings when I get home.

Originally Posted by Dennis Frie

Year, the Arduino and the analog comparator with a few components is pretty simple and works perfect. For a DIY project I also prefer the analog comparator rather than the LM1881.

No worries, I will continue with the Arduino OSD, but I will also make the few changes needed to make it compatible with SimpleOSD. Hopefully I can make the same code work on both Arduino and SimpleOSD, so you can just outcomment 2-3 lines to choose the Arduino version or SimpleOSD.

The e-osd would have been perfect if it had RX breaked out - and preferable a bit more memory.

I'm going to Zermatt in a couple of hours and will be away for 2 weeks. Hopefully I will be able to get a couple of flights and get some ground recordings when I get home.

What about the g-osd?

Have a nice holiday!

The G-OSD also uses a atmega88 so it has less space than the current code requires.
You'd need to trim down the code or if you can, replace the IC.

Dennis have a good time on vacation!

Dennis,
Have a good holiday, mine is over.

May be, when you are back again, I will have my OSD prototype (hope will run OK).
Ciao, Carlo.

Originally Posted by Dennis Frie

Check page 1

i would prefer arduino nano comparing it with arduino pro mini + FTDI converter in terms of price and simplicity.what do u say?

Yes Dennis has ordered the Arduino nano from dealextreme which is extremly well priced. And andreas77 has already got it and it works.

Thanks Dennis and Andreas,

Great little project, had the arduino on hand and only one trip to Radio Shack for the diodes. $1.81 later and we have OSD. I used the original schematic, my changes were R1 is a pair of 470 ohm, (234ohm) and all I had on hand was a 15turn 100k pot. Took lots of tuning but got her crisp and on board. Pictures don't do it justice.

Using a Aiptek 720P camera, I used 19 and 29 on topline, 222 and 240 on butline, to get them to fit in the black bar.

I've got a couple GPS's and a current sensor on there way to tinker with next.

Couple notes: be sure and connect grds to all equipment, don't forget power to Arduino. LOL

Useable OSD will come later, just wanted to try it out. Cool Project Thanks

This would also look like pro....

I'm wondering where are we connecting the GPS and current sensor, battery voltage on the arduino??

Arduino site shows this :

This library allows you to communicate with I2C / TWI devices. On most Arduino boards, SDA (data line) is on analog input pin 4, and SCL (clock line) is on analog input pin 5. On the Arduino Mega, SDA is digital pin 20 and SCL is 21.

So am I safe to assume pin4 and pin5, and put both on the same pins??

Thanks as always for any help.

Originally Posted by mrfliboy

I'm wondering where are we connecting the GPS and current sensor, battery voltage on the arduino??

Arduino site shows this :

This library allows you to communicate with I2C / TWI devices. On most Arduino boards, SDA (data line) is on analog input pin 4, and SCL (clock line) is on analog input pin 5. On the Arduino Mega, SDA is digital pin 20 and SCL is 21.

So am I safe to assume pin4 and pin5, and put both on the same pins??

Thanks as always for any help.

Hi fliboy,
This prototype OSD under development do not use I2C bus to comunicate with sensors and GPS.
GPS use serial pins RX/TX of arduino.
Other stuffs like Battery voltage and Current sensor and (may be) others, use analog input pins.
See as preliminary ref this diagram http://www.rcgroups.com/forums/showp...&postcount=102

Ciao, Carlo

Originally Posted by carlonb

Hi fliboy,
This prototype OSD under development do not use I2C bus to comunicate with sensors and GPS.
GPS use serial pins RX/TX of arduino.
Other stuffs like Battery voltage and Current sensor and (may be) others, use analog input pins.
See as preliminary ref this diagram http://www.rcgroups.com/forums/showp...&postcount=102

Ciao, Carlo

Thanks so much, read the thread a few times and missed that. LOL Thanks again

http://cgi.ebay.com/Arduino-Pro-Mini...item4155277cf4

Will this one work?
not a bad price

Originally Posted by IceWind

The G-OSD also uses a atmega88 so it has less space than the current code requires.
You'd need to trim down the code or if you can, replace the IC.

Ok, thanks. Replacing the IC seems like more trouble than it's worth.

Originally Posted by mrfliboy

I'm wondering where are we connecting the GPS and current sensor, battery voltage on the arduino??

Originally Posted by carlonb

See as preliminary ref this diagram http://www.rcgroups.com/forums/showp...&postcount=102

This circuit diagram is not the "official" one, it's just something I drew with features I would like to see in the future. For example, battery voltage and RSSI are currently not implemented in the code. For now, the only external sensors supported are GPS and current sensor. Like carlonb said, GPS connects to TX and RX pins, current sensor should be connected to A1.

Dennis is really the one doing all the development, he should have all the credit. I'm still just trying to learn how this thing works, maybe someday I can contribute to the development.

/Andreas

This circuit diagram is not the "official" one, it's just something I drew with features I would like to see in the future. For example, battery voltage and RSSI are currently not implemented in the code. For now, the only external sensors supported are GPS and current sensor. Like carlonb said, GPS connects to TX and RX pins, current sensor should be connected to A1.

/Andreas[/QUOTE]

Thanks for the info, I actually just made up your voltage divider and hooked it all up to realize its not setup yet. LOL So I gather theres no pin yet to show battery voltage?? Thanks again

duplicate post

Dear Dennis,

here a small update.
Your OSD works on the bread board now. Thank you very much.
Now I have to create a final one using a Arduino Mini Pro. Maybe I have to customize the code a little bit to meet my preferences.

Thanks.

I'll also soon start to order the parts ...

@mrflyboy - I'm also interesed in that voltage readout

@VRquaeler - nice, please share and show what will you change!

Originally Posted by VRquaeler

Dear Dennis,

here a small update.
Your OSD works on the bread board now. Thank you very much.
Now I have to create a final one using a Arduino Mini Pro. Maybe I have to customize the code a little bit to meet my preferences.

Thanks.

LM1881 is not too complex (8 pin chip, 2 x 100n cap, 1 resistor) and gives good results. But it's true that it's more complex than an almost direct connection of vid signal to the chip.

Alright a little progress has been made and a few steps back. For me to get any voltage/cureent sense reading, after startup, if I remove pin6 and reconnect I get a reading.

I just received this GPS http://www.foxtechfpv.com/10hz-gps-m...osd-p-248.html

Which is this chip http://www.locosystech.com/product.php?zln=en&id=19

When connected I get this:

MOV00466 (0 min 17 sec)

We be having fun now. All ideas and suggestions appreciated.

BTW I'm using the original schematic in post1 Thanks as always

For voltage-readout, just add a voltage-divider, use an analog-input, read it, and scale it to match the voltage-divider

I will update the code with support for voltage-reading when I get home - but its more or less the same code used for current-sensing.

Originally Posted by andreas77

Nice work there Dennis, and thanks for sharing it! I've ordered one of those Arduino nano´s + GPS from DE, so hopefully I will be able to try it out!

Are you planning to design a PCB for it also? A simple single layer PCB that is easy to DIY would be a nice addition! I might give it a try myself, but I'm not sure I have the skill.. I'm struggling to learn Eagle right now, so we'll see where it ends up.. So far I've started working on the schematic, would be nice to have your input. Does it look right to you?

Do you think it's a good idea to use the onboard regulator on the nano to power it + the GPS, or would it be better to use an external reg? The datasheet says it can handle 6-20V input but recommends 7-12V, so I guess powering it from a 3S LiPo would be ok but 4S would be pushing it?

As you can see I've also added RSSI input (A3), battery voltage input (A0) + one extra analog input (A2) for future development.. Do you think there is enough processing power left to add those things?

Warning! Please be advised that this schematic is just a draft. It has not been tested and verified to work!



/Andreas

I fried my nano using this layout. DO NOT use 12V for VIN on Your Arduino nano! I had ~11.6V attached.

Btw I didn't succeed with original schema either, it just wouldn't work for me. Can anyone post more images of final work and write pinouts?

Jancis,

Check your hardware circuit, the original schematic works very good.

Originally Posted by mrfliboy

Alright a little progress has been made and a few steps back. For me to get any voltage/cureent sense reading, after startup, if I remove pin6 and reconnect I get a reading.

I just received this GPS http://www.foxtechfpv.com/10hz-gps-m...osd-p-248.html

Which is this chip http://www.locosystech.com/product.php?zln=en&id=19

When connected I get this: http://www.youtube.com/watch?v=oSkOh5hsr6g

We be having fun now. All ideas and suggestions appreciated.

BTW I'm using the original schematic in post1 Thanks as always

Looks like incorrect baud rate for your GPS. Do you know the baud rate of this GPS? I did a quick google search and came up with 38400 baud, but I'm not 100% sure it's correct (hard to find a solid answer). If it is 38400, try changing this line:

UBRR0L = 103;

to this:

UBRR0L = 25;

You can calculate this number yourself using this formula:

F_CPU / 16 / BAUD_RATE - 1, where F_CPU = 16000000

(for 38400 baud rate => 16000000 / 16 / 38400 - 1 = 25.042 = 25 (round to closest integer))

/Andreas

Originally Posted by Jancis

I fried my nano using this layout. DO NOT use 12V for VIN on Your Arduino nano! I had ~11.6V attached.

Btw I didn't succeed with original schema either, it just wouldn't work for me. Can anyone post more images of final work and write pinouts?

I'm sorry you fried your arduino! The only reason I posted that schematic was because I was working on a PCB design and wanted Dennis to have a look at the it before I continued. As you can see, I clearly stated that it was just a draft and that it had not been tested and I've stated it again in later posts, but for some reason people keep referring to it. I think I'll just remove it if I can, to avoid further confusion..

That being said, I've looked at the schematic again and I can't find anything wrong with it (maybe someone else can?). About the input voltage, this is a quote from the product description at arduino.cc

Input Voltage (recommended) 7-12 V
Input Voltage (limits) 6-20 V

Are you sure you connected the unregulated external power to VIN (pin 30)?

Did you have a GPS connected? In that case, maybe the onboard regulator couldn't handle the extre current draw of the GPS.

In any case, Dennis advised not to use the onboard regulator, but to use an external one becuse of heat issues. (If you use an external regulator, it needs to be connected to the 5V pin (pin 27))

Please only use the schematics provided by Dennis here and here.

/Andreas

Originally Posted by andreas77

Looks like incorrect baud rate for your GPS. Do you know the baud rate of this GPS? I did a quick google search and came up with 38400 baud, but I'm not 100% sure it's correct (hard to find a solid answer). If it is 38400, try changing this line:

to this:

You can calculate this number yourself using this formula:

F_CPU / 16 / BAUD_RATE - 1, where F_CPU = 16000000

(for 38400 baud rate => 16000000 / 16 / 38400 - 1 = 25.042 = 25 (round to closest integer))

/Andreas

Oh, I forgot one thing, also change this:

Serial.begin(9600);

to this:

Serial.begin(38400);

or whatever baud rate your GPS is using..

/Andreas

Originally Posted by andreas77

Oh, I forgot one thing, also change this:



to this:



or whatever baud rate your GPS is using..

/Andreas

Perfecto, after verifying the gps was good using my DOSD, I went a made the code changes suggested and we now have the osd recognizing the gps. 9 sats and only took a minute or 2 to get them.

I believe I still need to change some lat/lon numbers to show generally my location??

Home arrow is not working, and alt is off a bit No complaints here.

Still having to unplug pin6 and reconnect to get voltage, but than again I'm running thru the voltage divider and not a current sensor. Next item to order...$7 current sensor (digikey)

Thanks again

Originally Posted by mrfliboy

Perfecto, after verifying the gps was good using my DOSD, I went a made the code changes suggested and we now have the osd recognizing the gps. Clock is running, speed went to 0.0 and Alt is blank. WooHoo. Raining outside right now but will test for actual sats tomorrow. Thanks

I believe I still need to change some lat/lon numbers to show generally my location?? Thanks again

Nice! For the moment, I don't think LOS calculation and home arrow will work where you are (in the US?), right now it only works accurately if your in or close to Denmark. I think Dennis said he will fix this eventually, after he has done some more testing of the current version.

Originally Posted by andreas77

Are you sure you connected the unregulated external power to VIN (pin 30)?

Yup, It was VIN, pin30.

Originally Posted by andreas77

Did you have a GPS connected? In that case, maybe the onboard regulator couldn't handle the extre current draw of the GPS.

No, didn't connect GPS yet. I want something to appear with minimum components enabled.. so that it at least works and then I can build up whatever I want.

Anyway, I totally agree I am extremly lame with electronics. I can code stuff, but all those electronical components are hard to learn for me.

I connected everything on breadbord as it was on schema, but no go. I still have 2 normal sized arduinos I can test with, I'd like to get at least some output. So I have this camera, 3 wires (+12/ground/video), battery and transmitter. I just hook into video and ground wire and add those to breadboard. Arduino is powered via computer USB port, but nothing except camera image is displayed on TV.

Can Anyone get more pictures of connections and components? Thanks

resistors, they don't have polarity right? diodes have black line along side that also has that line on schematics and what about capacitator? it doesn't have polarity (flow direction), does it?

Starting to build mine tonight. Got all the big parts, the small parts are somewhere around. Using a Arduino Mini v4 instead of a Pro but it's also 16MHz, only 16kB of memory but that should do fine (does it?).

Only have to find my compiler.

Sorry for the ignorant question but the code that is included in the .TXT file should be copy/pasted in the Arduino IDE?
Thanks in advance
Tassos

Originally Posted by cybervet

Sorry for the ignorant question but the code that is included in the .TXT file should be copy/pasted in the Arduino IDE?
Thanks in advance
Tassos

I just changed the .txt to .pde and it works fine

Andreas have you put your osd with the dealextreme gps already in the plane? Do you have a recorder? I'm anxious to see if that 1Hz dealextreme gps is sufficient...

A 1Hz GPS is sufficient as long as you don't plan to use it for auto pilot, high speed flying (>80km/h) or short range aerobatics. Even with a antenna tracker (not part of this project but tested with another OSD) a position each second is fine.

This GPS looks good and the price looks good too. Anyone using it?

http://www.rcgroups.com/forums/showthread.php?t=1169626

Originally Posted by Dennis Frie

The dimming of the text background is very easy. It would be nice to add a black outline to the characters, but that would require another way to blast the pixels or some timing skills
I haven't found any solution, unfortunately.

One way could be adding a black pixel (dark background) after te last white pixel. This gives at least a shadow in het horizontal direction.

Originally Posted by Jancis

Yup, It was VIN, pin30.


No, didn't connect GPS yet. I want something to appear with minimum components enabled.. so that it at least works and then I can build up whatever I want.

Anyway, I totally agree I am extremly lame with electronics. I can code stuff, but all those electronical components are hard to learn for me.

I connected everything on breadbord as it was on schema, but no go. I still have 2 normal sized arduinos I can test with, I'd like to get at least some output. So I have this camera, 3 wires (+12/ground/video), battery and transmitter. I just hook into video and ground wire and add those to breadboard. Arduino is powered via computer USB port, but nothing except camera image is displayed on TV.

Can Anyone get more pictures of connections and components? Thanks

resistors, they don't have polarity right? diodes have black line along side that also has that line on schematics and what about capacitator? it doesn't have polarity (flow direction), does it?

Here is a picture of my breadboard version, hope it helps!



I'm using this schematic. (Read about it here)

Originally Posted by msev

Andreas have you put your osd with the dealextreme gps already in the plane? Do you have a recorder? I'm anxious to see if that 1Hz dealextreme gps is sufficient...

No I haven't, sorry. When I do, I will be sure to post a video of it here.

Still no image overlay on my OSD. Signals are okay for AIN0 and AIN1. Perhaps a difference between the Arduino Mini v4 I have and the Arduino Nano v3/Mini Pro?

However, the GPS (EM-411) gets it's initial data to limit number of the sentences and got it's first cold start fix after 2 months within 18 seconds laying indoor on the kitchen table.

Also ordered an Allegro ACS756 current sensor. They're pretty cheap, accurate, easy to interface and used in the Eagle Tree Systems eLogger as well. Got one for only €7,44 without shipping.

Originally Posted by andreas77

Here is a picture of my breadboard version, hope it helps!

I see you're using a zener diode for D5, what voltage?

Originally Posted by Sleurhutje

I see you're using a zener diode for D5, what voltage?

I'm reading this thread just loosely and as such don't delved deep into the cirquit, but it's my impression he operates the zener in foreward direction which means he just had no regular diode laying around. So IMHO any silizium diode should do.

Just my 2¢ of course.

Markus

Originally Posted by markus123456

I'm reading this thread just loosely and as such don't delved deep into the cirquit, but it's my impression he operates the zener in foreward direction which means he just had no regular diode laying around. So IMHO any silizium diode should do.

The other two diodes ar just 1N4148's, I doubt if he didn't have any others.

The sync signal is a negative signal, so the zener isn't in forward direction for the sync signal, only for the video signal. Somewhere in this threat the use of a zener was mentioned.

Originally Posted by Sleurhutje

The other two diodes ar just 1N4148's, I doubt if he didn't have any others.

The sync signal is a negative signal, so the zener isn't in forward direction for the sync signal, only for the video signal. Somewhere in this threat the use of a zener was mentioned.

This Maybe?

http://www.rcgroups.com/forums/showp...&postcount=204

Originally Posted by Sleurhutje

I see you're using a zener diode for D5, what voltage?

Take a look at this post by Dennis:

Originally Posted by Dennis Frie

Let's just forget the "splitting of video-signal" for a moment. I will get back to that.
The hardware-design is not completely perfect. If you take a look at commercial products used to detect video-sync, the circuit is far more sophisticated. This is an easy and pretty good way to do it, but it might not be perfect.

The main problem is, that some cameras will need more than 600 mv bias to get the sync-pulse raised above ground. Preferably I would have used a 0.7-0.8 volt zener-diode, but I also wanted to make it as simple as possible - and with standard components. Using a single 4148 diode gives you around 0.6-0.7 volt. While this should be fine for normal cameras, it's not quite enough if you use for example the cheap HK camera. Replacing R3 with a 100K ohm resistor will do the trick, but i'm not a big fan of a pull-down resistor that high. The trick with the PWM signal was just another way to create the voltage that could have been obtained with a zener-diode.

So, the short version. If don't want to "test", I would either recommend Schematic 1 and use a 0.8 volt zener-diode instead of D5, or just use the schematic on page 1.

Be aware that the 50 ohm dimming resistor might be too small. Better give like 100 ohm a shot.

I'm no expert on analog electronics and I'm not sure if he meant that you should use a zener diode with a 0.7-0.8v zener voltage. (I can't even find one with a zener voltage in that range) The way I interpreted it was that a zener diode have a sligthly higher forward voltage drop than regular diodes which might give you a more stable sync with some cameras. In that case I don't think the zener voltage matters, I just used a 5.6v that I had laying around. Otherwise, just use a standard 1n4148 to start with and only bother with this if you have problems with the sync.

Hi all,
Just today I tried my Dennis-OSD prototype and is running good without GPS.
I used this schematic.
Now I have connected this GPS unit http://flytron.com/osd-headtrackers/...ps-module.html but after an hour not data from it, I see only dots.
This GPS after switch it on has a blue led always ON, and a red led flashing for about a minute after that the red led go OFF, what it mean ?
Confirm to me please that Tx of GPS must go to Rx of Arduino and Rx of GPS must go to Tx of Arduino

Note I am using Arduino 2009 for testing.

Ciao, Carlo

Originally Posted by carlonb

Hi all,
Just today I tried my Dennis-OSD prototype and is running good without GPS.
I used this schematic.
Now I have connected this GPS unit http://flytron.com/osd-headtrackers/...ps-module.html but after an hour not data from it, I see only dots.
This GPS after switch it on has a blue led always ON, and a red led flashing for about a minute after that the red led go OFF, what it mean ?
Confirm to me please that Tx of GPS must go to Rx of Arduino and Rx of GPS must go to Tx of Arduino

Note I am using Arduino 2009 for testing.

Ciao, Carlo

Quoted by myself after some tests on my GPS:
Red LED flashing: Attempting to FIX
Red LED Off: FIX Ok
Opening Serial Monitor of Arduino I see the two gps string GPRMC and GPGGA and I can see correct values (time, lat long, fix, n. of satellites used, altitude). But on arduino monitor I can see once a time I open it.

Still not data on the screen of my Fatshark, only camera image.

Help!
Ciao, Carlo

Sorry for duplication

New design

Looks beautiful is it working for you already? is the current sensor already on the board?

That is fabulous evvaldis.


Is anyone working on lat/lon code changes for us non Denmark people?? LOL

Mine seems to be working pretty good. I actually got a LOS reading (15) and home arrow moved 180 degree with 191 underneath, but nothing consistent. Not quite ready for my quad yet.

evvaldis

Wow that looks sweet!
Good work!!

Originally Posted by msev

Looks beautiful is it working for you already? is the current sensor already on the board?

Thanks, yes it works Current sensor will be on separate pcb.
http://www.flytron.com/pdf/light_current_sensor.pdf (based on ina139 chip).

Hi, there's still no success with OSD, I tried this schema on that cheap HK FPV kit and also swapped that camera supplied with canon camera composite out but still no overlay.
G-OSD works ok on both cameras but none from this OSD.

Are these components correct?

Back from holiday

Originally Posted by Jancis

I fried my nano using this layout. DO NOT use 12V for VIN on Your Arduino nano! I had ~11.6V attached.

Btw I didn't succeed with original schema either, it just wouldn't work for me. Can anyone post more images of final work and write pinouts?

I think the input is called RAW on the Arduino Pro mini, not sure what it's called on nano. If you use the right pin you should be able to use 6-20 volts input.

Originally Posted by andreas77

In any case, Dennis advised not to use the onboard regulator, but to use an external one becuse of heat issues. (If you use an external regulator, it needs to be connected to the 5V pin (pin 27))
/Andreas

I think it's rated 80 mA - but off course it will depend on the input voltage. If you use the onboard regulator, just be sure to check the temperature of the regulator. OSD alone is no problem, but if you use the onboard regulator to power GPS and additional sensors it might draw too much current.
If it works on the ground, it should also work in the air with some airflow.

Originally Posted by mrfliboy

Home arrow is not working, and alt is off a bit No complaints here.

Still having to unplug pin6 and reconnect to get voltage, but than again I'm running thru the voltage divider and not a current sensor. Next item to order...$7 current sensor (digikey)

Thanks again

Voltage reading and updated code for current-sensor will be done soon.
Haven't decided how to implement full GPS support - it will take quite a few float calculations to do it perfect. Hopefully I can make an approksimation with just a single cos/sin that will be a lot faster and plenty for FPV use.

Originally Posted by Sleurhutje

One way could be adding a black pixel (dark background) after te last white pixel. This gives at least a shadow in het horizontal direction.

Year, but unfortunately that's not as easy as it sounds. The characters are shifted out using SPI. Timing the black pixel would require quite a few changes.

Originally Posted by mrfliboy

Is anyone working on lat/lon code changes for us non Denmark people?? LOL

Hopefully I will get some time to look at it this week - but I Just have a wet and dirty tent, 30 kg equipment that needs to be unpacked etc.
If you change a thing or two you should be able to use it without problems at your locations.



And damn, just gotta bring a FPV plane to the alps next year.

Wow really nice photos ,...you are right being in the snow it was scorching hot on lower altitude ..

Originally Posted by msev

Wow really nice photos ,...you are right being in the snow it was scorching hot on lower altitude ..

Thanks.
Year, even at 1600 meters (Saas fee, Saas Grund and Zermatt) it was around 30 degrees now and then. I can only imagine the temperature at sea-level

The temperature at 4000 meters was a lot better.

But it did get a bit cold now and then :P

Welcome back Dennis,
Awesome pics on top of the alps, here on the flat lands on the other side of alps (North of Italy) is very hot 35...38°C.

Now is time to work hard , I already have my runnig prototype and have connected my GPS -> http://www.rcgroups.com/forums/showp...&postcount=204.
On my Fatshark gogles I can see images and OSD fields, but about GPS I still see "....." and no data after GPS fix.
Only on serial monitor of arduino (I use Arduino 2009) some time I can see 2 correct strings, but many time the strings are corrupted.

What happen ?
Thanks for your job, ciao, Carlo.

Originally Posted by carlonb

Welcome back Dennis,
Awesome pics on top of the alps, here on the flat lands on the other side of alps (North of Italy) is very hot 35...38°C.

Now is time to work hard , I already have my runnig prototype and have connected my GPS -> http://www.rcgroups.com/forums/showp...&postcount=204.
On my Fatshark gogles I can see images and OSD fields, but about GPS I still see "....." and no data after GPS fix.
Only on serial monitor of arduino (I use Arduino 2009) some time I can see 2 correct strings, but many time the strings are corrupted.

What happen ?
Thanks for your job, ciao, Carlo.

The GPS from flytron uses 9600 baud as default - so you should be able to connect it and use the current software-version without any changes.

have you checked the update interval? And how can you see that the strings are corrupted?
Please note, that you probably want be able to connect the GPS and computer/USB at the same time.

The time in left corner should show as soon as you connect the gps.

Dennis what will be your next thing to do, the story of making this osd is very nice to read
Marko

Originally Posted by Dennis Frie

The GPS from flytron uses 9600 baud as default - so you should be able to connect it and use the current software-version without any changes.

have you checked the update interval? And how can you see that the strings are corrupted?
Please note, that you probably want be able to connect the GPS and computer/USB at the same time.

The time in left corner should show as soon as you connect the gps.

Hi Dennis,
I can see (some time) the 2 GPS string (Good or corrupted) with arduino serial monitor without having enabled the part of code you forseen for debug (if (1=0)....
I know this situation means that I have connected Arduino USB and GPS rx/tx at the same time and may be not fine.Connecting only rx/tx of GPS to arduino I can't see any data, nor time in left corner, only dots as per other datas.
The other strange think is that I connected TX of gps to TX of Arduino2009!!! Inverting this I can't receive any string on arduino serial monitor.
I verified that the update interval (do you mean 5Hz refresh?) and the command string is the same of yours in the sketch.

This evening I will try more, may be that TTL levels of RX/TX of GPS are not good for 5V supply/communication with arduino as data sheet show 3.3V TTL levels.

Ciao, Carlo

Originally Posted by msev

Dennis what will be your next thing to do, the story of making this osd is very nice to read
Marko

This should be done soon:
- Battery voltage
- Updated current sensor code
- Support for SimpleOSD 16 mhz (thanks to flytron - more about this later)

And this is on the to-do list;
- Flight summary
- Updated analyzing of GPS data to support worldwide

Ideas are always welcome, but support for extra sensors etc. (accelerometer etc) will not be made atm.