DIY RC plane using the ATtiny44 with an nRF24L01 as a receiver

I wanted to convert a foam glider into an RC plane. As the plane is rather small I needed to create a small lightweight receiver and decided to use the ATtiny44.

• Use an old ESky 0404 35MHz 4 channel radio controller as the transmitter decoding the PPM signals exposed by the training port socket - Working
• Transmit the decoded PPM signals using one RX-Nano to another RX-Nano to test it works - Working
• Get ATtiny44 to receive the same signals - Working
• Get ATtiny to drive a servo motor - Working
• Create a circuit so the ATtiny can drive the small motors - Currently using a transistor, but will try using a mosfet to see if I can reduce the voltage drop.
• Get the BMP180 pressure sensor working with the ATtiny using soft I2C (SoftI2CMaster) - (because the SDA and SCL are being used for the nrf24l01) - to do later

With the latest update the PPM decoder and transmitter are working properly.

Now I am lacking some power in the motor, so I will replace the 2N2222 with a K12N06L mosfet.

The transmitter

This is simply an RF-Nano powered by the radio's default batteries, using a buck converter to convert the 12V to 5V. The signal has been obtained by soldering a wire to the signal pin on the inside of the trainer port, and connecting it to one of the arduino GPIOs.

The receiver

This is an ATtiny44 with an nRF24L01 powered by a 3.4v LiPo battery.

The module

Circuit diagram

Refinements

Possibly use a library rather, to decode the PPM signal, that does not make use of micros()

Lessons learned - for now

• Solder an SPI header to the board allowing me to program the ATtiny so it doesn't need to be swapped out for programming.