24 octobre 2008
First attempts to use a lcd. It is connected with 8 wires for datas and 3 for controls. Connection with 4 wires could be another possibility. The soft library I used is a bit slow to display: there is too much temporisation between caracters. White on blue is not too bad, and led Backlight improve a lot the readability.
21 octobre 2008
The transmitter is based on a Arduino Diecemilla with an Xbee shield and an Xbee pro. Stick are connected to the Diecemilla though a small board. The +5V and the ground wires are directly soldered on the Arduino and distributed to each stick through the small board (red and blue wire on the picture).
On the Shield, jumper must be set to PWR and XBEE.
The large vertical board above the battery is just to keep the Power Switch in place, there is no use at all of the electronic on this board. 5 cells are fine to power the Diecemilla and the Xbee.
The Xbees are preconfigured through a small adaptor board connected to the PC by USB. Baud rate must be set to 38400, no parity, 8 bits, no flow control. The rest of the settings can be found on the excellent french site o24rcp for the transmitter and for the receiver.
For the receiver, an Sparkfun Wee is connected to an XBEE: TX to RX, RX to TX, +3.3V and ground. Power is done by a 4.8v and a regulator to 3.3v, and digital output 0 to 6 to control the servos.
The software can be downloaded with avr-dude. Here is the hex image for the transmitter and for the receiver.
Protocol bewteen the 2 Xbees currently use 5 bytes including a CRC.
Have fun, do not hesitate to send me questions or tell me your feedback if you made something out of that.
15 octobre 2008
13 octobre 2008
After some fixes within the software, I am now getting closer to the first fly. I did some preliminary tests of servos and speed controller. All behaves good. The tail and rudder servos are bad quality and they move by small steps. But they behave the same than with a 12Z Futaba radio.
Speed controller are ok, and motor on seems to behave correctly. We'll see what happens when the model will be several ten's meter from the transmitter. First fly is coming soon !
The receiver has been quickly wrapped around with heat retractable scotch.
05 octobre 2008
Here is a video showing the transmitter and receiver working. Transmission between transmitter and receiver is numeric. The receiver decode the servo position given in bytes and transform it in the right pulse and timing to move the servo.
This is the prototype of the receiver. It is much too big and too heavy, but it's just a prototype. It's not easy to sold all this stuff. When mounting it, I made a mistake with the Wee board that I sold at the wrong position. I had to unsold it and to move it, it was quite a nightmare.