Arduino based RC flying projects , closer look
Lastly I was a lot involved into use of Arduino IDE , for some devices based on Arduino .
In closer look of Arduino I have followed conclusions .
Fusebits of Arduino MCU are set for home play with MCU by young hobbyist - but not for RC use in jammed and glitched environment , as for sure is ESC , some radios , cameras step-up converters , Video TX , etc. etc.
So what we got :
- ext. crystal (low power) - Unfortunate clock will work badly in environment what are jammed and glitched and power is not good quality and noisy , RC is exactly such environment .
In this cases manufacturer recommend Full-Swing Crystal option to avoid any problems .
- Brown-out detect is 2,7V , so it should be at 4,3V . In so low power , MCU just "play" that working correctly but it not . In case of communication cable are in , MCU alredy start clock running and can case bad memory and counting malfunctions . MCU should start only when the battery power is connected . In old days when was used RS232 and MAX232 chip such problem doesn't existed , but now USB cable have as normally 3,3V pull-ups on TX RX lines - what in fact made MCU to work .
That can explain why Arduino use for programing special FTDI cable with DTR signal to bypass this issue , except of commercial reason .
- Bootloader 2048kb size , there are smaller exist . Need to use special cable with DTR signal - that bad . There is not problem if on the board exist FTDI chip - but if not there is complication . Personally I have not such working cable .
So I decide that all of this can be repaired .
At first fuse bits must be set in proper way for use in RC environment .
So we set : :
- Brown-out Detect 4,3V
- Ext. Quartz in option of Full-Swing
To do that we need ISP programmer , along with ISP opportunity we can use smaller Bootloader - in this case Megaload (but can be aby other) .
Since this moment we do not need special cable with DTR , we can use any USB->UART TTL bridge , of any brand , even RS232 with MAX232 if anyone still have such old PC (most still have RS232 in PC) .
- Bootloader size 512word (1024kb - half size of original)
So Fusebits should look like that :
Bootloader files we can download from www.microsyl.com , compilation is more easy than settings of MultiiWiiCopter .
For lazy I add compiled files to this post . Also for other MCU .
About ISP programmer - there are many cheap solutions - I recommend LPT port and 5 wires - can be used ICprog or Bascom (schema of LPT ISP in help file - demo works excellent) .
Well , surprisly I managed that Arduino dudes , for some unknown reasons decided to hide your own compiled .HEX file - why ? that some kind of paranoid . We give you for free nice shiny pen - you can write anything you want but you must buy special ink .
Anyway we still can use that file for our purposes .
At begin in Windows we must set - show hidden files , also is good to unmark to show file extensions . That will be useful in next steps .
Now we can run Arduino IDE . When we want to compile out program we press and hold SHIFT button - then we press compile "play" button , at console on bottom of screen we have full path for out "hidden" compiled .HEX file .
Now we run Megaload bootloader and show him the .HEX flash file .
Now we simply connect power to the board - or on the board we simply press RESET button - update will start automatically . We close Megaload .
Fast and nice .
Here are samples of RC devices based on Arduino , both are working excellent with simple Prolific and other OTi cable , GUI of MultiWii works also excellent .
MultiWii board by FPV4EVER
Ardupilot - for this one I will now back soon and made it fly
Fuse bits should be fixed .
By the way exchanged bootloader for more "accurate" .
At the end movie showing all procedure :
I must admit that having Megaload we can use files compiled by any compiler , like raw AVR-GCC , ICCAVR , Bascom etc.
Also FDTI cable with DTR is still working on it , but DTR is not used .
I hope maybe this info will be useful for anyone .
Last edited by remzibi; Oct 27, 2011 at 06:47 AM.
USB-UART Tx Line driver
Hi, my computer doesn't recognise my remzibis usb. It says that the driver for the USB-UART Tx Line are not installed. Does anyone knows where can I get them?.
So far my computer is not conecting to my remzibis osd and I wonder if this is going to be the problem.
I wanted to get your email to buy a OSD that you manufacture, it will be possible is available to ARGENTINA??
I hope your answer, I would greatly appreciate, since I can not find more data on you and your products ...
good flights, a warm hug to you!
To fast contact please write PM to me (simply press envelope symbol below my avatar) .
I was wondering if I could buy the OSD that you manufacture? I live in the US and would love to have one of your OSD. They look awesome!
I would really appreciate it if you would sell me one of these. Please email or call me at: firstname.lastname@example.org
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