In 2006, when I started to think about R/C models, I bought cheapest 4 channel transmitter with idea, that if I’ll need more – I’ll make it:-)
Somewhere between 2007 and 2008, during discussion on Alexrc forum, idea of very flexible and fully programmable transmitter were born.
Idea was to define model inside transmitter using basic blocks (sum, multiply etc) and connections between inputs, blocks and outputs.
In 2008 I made a universal board for my projects using Atmega8L and LCD screen from Siemens S65 phone.
In 2009 I replaced Atmega8L with Atmega88 – it allowed to safely (within cpu specs) increase cpu clock from 7MHz up to 11MHz while still running at 3V. And since then real story begins:-)
At the end of 2009 I had some things finished: generating ppm, calculating blocks and basics of user interface (menu, keyboard). And then project stuck for almost 3 years.
I tried to make it too universal, and it didn’t worked for UI. During these years I used simple transmitters – there were enough for my planes. But at the end Tricopter appeared:-) Problems with arming control board and need for more channels resurrected old project.
So, at the end od 2012 i removed some code (mostly UI related), revised some assumption (store model definitions not only in flash, but also use eeprom for this), and project moved forward.
I put this board into empty old transmitter bought at about $2, added FrSky DHT module, connected all together and right now it could be used in real world:-)
At the beginning of 2013 code was usable in a field.
Meantime ready made Arduino boards became extremly cheap, so I added support for Atmega168 and Atmega328.
Another aspect was a LCD display – currently lcd from S65 is almost impossible to buy, so I started to look around for replacement. Luckily, there are some similar cheap 1.8″ TFT displays available on eBay, so I added support for them. After a while it appeared that this is almost the same display as released by Arduino team. So, hardware is getting to be simpler – just connect ready blocks instead of making own pcb for whole transmitter.
In 2014 I decided to put it more to public, so main code repository was moved to Github and more information started to appear on my site…