The theory behind the RC motor controller can be seen on the RC motor controller for PIC16F84 page. When I discovered the ATMEL controllers, I started to convert the code for my PIC to my atmel 90S1200. While converting, I  also wanted to implement overheating protection for the FETs , Lost signal indication and easy to hook up to the computer for software updates. The circuitry shown on this page is only for "one way" motor rotation - used on my Flying wing. But as can be seen on the PCB, its split up in 2 boards, one having the controller, with access to various outputs, and the other board is were all the "muscles" are placed. the muscles part of the controller can be replaced with whatever circuitry you might want.

The purpose is that I will only have one controller circuitry (the most expensive) and can change the "under cradle" to use the motor controller for RC-boats/cars (two way rotation) and for RC-flying (one way rotation) and even make it a RC-switch, with adjustable threshold.

Soon a 2 way version of the "under cradle" will be published, since I will be needing it my self, for my submarine.

The controller unit haves the following outputs:

• Over heating signal - (becomes high and stays high if the FETs are overheated (LED indication)- the PWM output is stopped only until the FETs are cooled down again)
• Signal fail - When the model is out of reach, transmitter is turned off, or the submarine has dived too far down. this signal will be raised and all PWM outputs are stopped.
• Idle Indication - When the stick is in programmed idle position, this output will be high.
• FULL back indication - The motor is running full backwards
• FULL forward indication - The motor is running full forwards
• Backward PWM signal out - To FETs for motor control
• Forward PWM signal out - To FETs for motor control

High = 5 Volt /max 20 mA

Besides the above features, the controller has a LED used for adjusting the controller to your transmitter settings. When first powered up, the controller has no settings stored inside - So the Adjustment LED flashes 5 times.

• Throttle stick is placed in full forward, and the button is pressed (4 Flashes).
• Throttle stick is placed in idle mode, and t he button is pressed (3 Flashes)
• Throttle stick is placed in full back, and t he button is pressed(2 flash).
• To save the Adjustment for storing , the button is pressed (1 Flash).

If the Adjustment LED does not flash any more, the settings are OK and stored, otherwise the LED will flash 5 times, and the settings adjustment will have to be done again (only if the Forward, Idle and Back are not in mentioned order).

If a new setting is needed, the Adjustment is triggered while powering up the circuitry to forcing it to enter the adjustment routine..  

The links below shows the version 21 of PCB.

View PCB of both motor controller and under cradle 

Download the above PCB in Protel 2.0 format

View SCH of controller board.

Download above SCH in PROTEL 2.0 format

Download .HEX file here

Fuse and lock bits are not set in the code, but should be: 

• LB1+LB2 = "1" 
• SPIEN = "0" 
• RCEN = "1" 

Bill Of Material - Controller board:

• 1 x (4.0 x 2.7 cm) printed circuit board
• 1 x Micro controller (AVR 90S1200 - Programmed with motor controller software version 21) 
• 1 x 3-pin 4 MHz ceramic resonator
• 1 x Low drop voltage regulator 5V/1A (LM2940)
• 1 x BC557 or equiv.
• 1 x 2.2 uF Kondensator
• 2 x 47 nF Kondensator
• 2 x 4.7 nF Kondensator
• 2 x LED
• 9 Resistors (details to come)
• 1 NTC Resistor (details to come)

Bill Of Material - Power board (one way):

• 1 x (4.0 x 2.7 cm) printed circuit board
• 2 x IRL3102 or equiv. (depending the application (IRL3102 - 61 Amp each))
• 2 x 1N4001 Diodes

Future :

An SMD version will be the next step, to improve size and weight.

Email me at - kimfmx@gmail.com