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Old Dec 29, 2012, 08:52 AM
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Originally Posted by dziedrius View Post
looking at BOM, I'm wondering how they are able to make so cheap minimOSD - HK sells it for 18.99, but you can get it for 16.88 shipped on ebay - and it has atmega328 and MAX7456 in it.
I was thinking the very same. I guess if one has a good hot air rework station, they could conceivably savage the chips.
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Old Dec 29, 2012, 09:12 AM
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Originally Posted by dziedrius View Post
looking at BOM, I'm wondering how they are able to make so cheap minimOSD - HK sells it for 18.99, but you can get it for 16.88 shipped on ebay - and it has atmega328 and MAX7456 in it.
Quote:
Originally Posted by rimshotcopter View Post
I was thinking the very same. I guess if one has a good hot air rework station, they could conceivably savage the chips.
I can get all parts, except MAX7456, for something like 10$ total. If you are actually producing a product and buy a couple of thousand components at a time, you can get them a LOT cheaper. Depending on the MAX7456 price, there is still a little margin if the production cost is minimal.

But yes, still incredible.

By the way..
MAX7456 can be sampled for free.
I have been using samples from Maxim for all testing/developing.
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Old Dec 29, 2012, 12:24 PM
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Just a few minor changes..
- Better ground plane
- Return-path for Atmega crystals a lot shorter, important to minimize noise
- Vcc added at I2C connecter, as a lot of I2C-boards have onboard regulator.
- Ground return-path improved for ADC reference decoupling

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Old Dec 29, 2012, 04:13 PM
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After a few beers...
Don't come tell me they don't add a bit of creativity


1) The slow decoupling-caps are meant as energy-storage, to maintain a stable supply-voltage. They have been placed, to act as a little filter if camera and video-transmitter are connected directly.
2 x 22uF, 10V, X5R, 1206
7 x 10uF, 10V, X5R, 0805

2) Theses caps are used to remove high-frequency noise, and supply the fast current needed for MAX7456 and Atmega328P.
5 x 100nF, 10V, X7R, 0805

3) This is used to AC-couple the output video-signal. The input-video signal is AC-coupled with a small 100nF capacitor, as the input is high-impedance.
2 x 47uF, 6.3V, tantalum, 1206

4) This is the voltage-divider used to measure battery-voltage. 3.3K and 10K have been chosen as default for 4S max.
1 x 3.3K 0805 1%
1 x 10K 0805 1%

5) Resistors used to set the video-impedance. The normal video-impedance is 70 ohm.
2 x 75R 0805 1%

6) Load crystals for Atmega 16MHz crystal
2 x 22pF, NP0, 0805 (perhaps 0603 as the space is a little tight)

7) Pull-up resistors for the Sync-signal etc. on MAX7456 and also a series-resistance on RSSI-input (can be used as any analog input)
4 x 1K 0805 1%

8) Pull-up resistor for Atmega reset-pin
1 x 10K 0805 1% (Note 10K resistor is also used in default voltage-divider)

9) Caps for the 3.3V regulator used for I2C devicces.
2 x 1uF, 10V, X7R 0805
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Old Dec 29, 2012, 04:33 PM
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Dennis,

Do you sleep?
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Old Dec 29, 2012, 04:43 PM
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Originally Posted by jalves View Post
Dennis,

Do you sleep?
I've had a few days of holiday and been away from all my electronic, work and studies - so I've actually been able to sleep more than a few hours the last couple of days. It's nice, I can recommend it

By the way, regarding video-telemetry. It might be possible to use offset on MAX7456 to push characters above first line and hide some lines. I haven't tried, just an idea.
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Old Dec 29, 2012, 11:30 PM
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if anybody wants to check this list to verify it accuracy to Dennis' updates it would be greatly appreciated - thanks
Bob

MAX7456-DIY-OSD-NOT-FINAL
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Old Dec 30, 2012, 04:10 AM
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Originally Posted by Dennis Frie View Post
Just a few minor changes..
- Better ground plane
- Return-path for Atmega crystals a lot shorter, important to minimize noise
- Vcc added at I2C connecter, as a lot of I2C-boards have onboard regulator.
- Ground return-path improved for ADC reference decoupling

So is this the design you had made with the isp header, or is this yet another new design?

What about that "first" design with isp-headers, did you assemble one and test it how it works?
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Old Dec 30, 2012, 06:07 AM
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Originally Posted by bob4432 View Post
if anybody wants to check this list to verify it accuracy to Dennis' updates it would be greatly appreciated - thanks
Bob

MAX7456-DIY-OSD-NOT-FINAL
Looks very good, thanks a lot
The X7R can be replaced with X5R if anyone don't plan to get the electronic above 85-degrees (shouldn't be a problem).
I've forgot the series resistor for the LED, adding an extra 1K should be fine. Possible I can ask you to add an extra 1K?
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Old Dec 30, 2012, 06:14 AM
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Originally Posted by msev View Post
So is this the design you had made with the isp header, or is this yet another new design?

What about that "first" design with isp-headers, did you assemble one and test it how it works?
It's the same design but with the changes mentioned.
The entire project started a few months ago, you can't be surprised by a revision of the PCB

Most people will never notice the difference between the 2 designs, but off course I will recommend the new one.

The PCB's with ISP-header have been shipped and should be somewhere in Denmark. I suppose they are either at the post-office or disappeared somewhere in all the christmas-mail.
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Old Dec 30, 2012, 08:07 AM
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If anyone uses Arduino, this is how MAX7456, PPM, MPU6050 and BMP085 should be connected



Works just fine, but i prefer a small PCB
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Old Dec 30, 2012, 10:53 AM
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Originally Posted by Dennis Frie View Post
If anyone uses Arduino, this is how MAX7456, PPM, MPU6050 and BMP085 should be connected



Works just fine, but i prefer a small PCB
Very cool indeed - I like it The one you helped me build with a Nano is a bit smaller and I've been flying with it - It too works just fine.

Looking forward to the other sensors hooked up. Mine just came in the mail - but you didn't put the MPU6050 or the BMP085 on the board did you?

Getting the new radio set up to choose channels Hope to see the menu soon !

So you opening up a shipping receiving department , or do we just purchase the boards from the folks that are building them? Are you going to test it first or do you think you would like a beginner like me to make a stab at it?

Thanks again Dennis for all the time into this.....

Rick
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Old Dec 30, 2012, 11:15 AM
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Originally Posted by RickEis View Post
Very cool indeed - I like it The one you helped me build with a Nano is a bit smaller and I've been flying with it - It too works just fine.

Looking forward to the other sensors hooked up. Mine just came in the mail - but you didn't put the MPU6050 or the BMP085 on the board did you?

Getting the new radio set up to choose channels Hope to see the menu soon !

So you opening up a shipping receiving department , or do we just purchase the boards from the folks that are building them? Are you going to test it first or do you think you would like a beginner like me to make a stab at it?

Thanks again Dennis for all the time into this.....

Rick
It was mainly posted for fun. It can be made pretty descent with a small Arduino

MPU6050 and BMP085 have been implemented, but the fine-tuning haven't been done yet. I need to test it in a plane to see how it behaves while pulling a few G and being mounted in a place with vibrations etc., but all the fancy calculations are done. (NTSC haven't been checked with pressure sensor)

Sounds good with the new radio. Which one did you get?

I don't have time to sell the OSD's, but everyone is welcome to make a few and sell. I don't mind to sell a few PCB's, but as 10 pieces inclusive shipping is 14$ from seeedstudio, it's not really worth it, as shipping from Denmark is quite expensive.

If you have never soldered SMD components before, it's gonna be a little difficult the first time. 0805-size components are not very difficult, but MAX7456 is a bit tricky.
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Last edited by Dennis Frie; Dec 30, 2012 at 11:27 AM.
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Old Dec 30, 2012, 01:35 PM
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Originally Posted by Dennis Frie View Post
It's the same design but with the changes mentioned.
The entire project started a few months ago, you can't be surprised by a revision of the PCB

Most people will never notice the difference between the 2 designs, but off course I will recommend the new one.

The PCB's with ISP-header have been shipped and should be somewhere in Denmark. I suppose they are either at the post-office or disappeared somewhere in all the christmas-mail.
I'm a bit confused about the versions,...So the first version is without ISP right, the second version is with ISP (and you will get pcbs for it and test them in the next few days right?) So the version you posted the design files is the second version? (the version that you'll get pcbs for.)
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Old Dec 30, 2012, 01:47 PM
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Parts list is updated w/ the additional 1K resistor . Also, for the imperial measurement people (like me), Dennis is talking about using the X5R type ceramic capacitor if you don't plan to get the electronics above 85C/185F.

Bob

Quote:
Originally Posted by bob4432 View Post
if anybody wants to check this list to verify it accuracy to Dennis' updates it would be greatly appreciated - thanks
Bob

MAX7456-DIY-OSD-NOT-FINAL
Quote:
Originally Posted by Dennis Frie View Post
Looks very good, thanks a lot
The X7R can be replaced with X5R if anyone don't plan to get the electronic above 85-degrees (shouldn't be a problem).
I've forgot the series resistor for the LED, adding an extra 1K should be fine. Possible I can ask you to add an extra 1K?
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