J-Tech Engineering - Radio Control Receiver and Servo Driver

Radio-Control Receiver

Superregenerative Radio Receiver and Servo Controller

The above image is of a production unit. Its dimensions are exactly 1"x2". As per the customer's request, the processor and other components on the board have been altered to not reveal the method of operation.

The following features were implemented on the board:

Processor - an 8-bit microcontroller, performing the following:
- On power-up, unconditionally rotate a servo to a "set" position;
- Analyse an incoming manchester coded data stream, allowing for broad tolerance of base-band duty cycle and frequency;
- Upon reception of the correct 8-bit code, (coded as a 16-bit word), drive the servo to a "release" position.
Radio Receiver - Superregenerative type: Although superregeneration is an older form of RF demodulation, this receiver type has some distinct advantages. Most notably, the unit requires no quartz-based crystals, oscillators or filters.
High mechanical shock tolerance: In production, the above board is mounted in a manner that allows its enclosure to tolerate forces of up to 10,000 Gs. This is one of the most remarkable achievements of the product.
Servo Actuator: This is the output stage of the unit, and drives a servo between two pre-set end-points.
In-system programming capability (not shown): The unit was designed with the ability to program the processor after placement on the circuit board. An additional custom programming socket was created, allowing the board to be connected directly to an industry standard device programmer.

Although the mounting technique employed for the above board is not shown, the unit is able to withstand extremes of force, and operates in widely varying temperatures. The unit must function in the rugged environment of logging in British Columbia (and the rest of the world), year 'round. The product was tested by subjecting units to repeated six meter drops onto a two inch thick steel plate, until failure. After several attempts, it was decided that if the unit could survive at least 25 impacts without incident, the design would be deemed production ready. The availability of only a few prototype radios for testing meant that the same one was used for multiple product drop tests. The beta unit survived well over 100 impacts, and continued to function to the end of testing.

This product is a component of a larger system used in the logging industry. General inquiries regarding purchasing can be directed to Johnson Industries at:

Johnson Industries, Logging Division

Inquiries regarding designing and programming with microcontrollers, superregenerative RF receivers, and working with servo motors can be directed to J-Tech Engineering. Please see the company info page for contact information.