We measured the weight of our airplanes against the weight of potato chips.
Filling the micro-airplane niche in 1998, Dynamics Unlimited quickly became the most innovative source for ultra-lightweight radios, motors and servos. This 1/2-gram controller was an excellent match for Dynamics Unlimited's 11-watt 5-gram motor. Delivering over 60 grams of thrust, this motor was the engine behind an all-up 37-gram aerobatic model airplane.
Circuit design, PCB layout and software are exclusively my work.
- On-board 25MHz MCU
- Variable speed
- In-flight reversibility
- Very high efficiency
- Automatic back-EMF start, no hall sensors or encoders needed
- 2.9V-4.2V operating voltage
- 3.5A continuous output
- High-speed commutation to handle small motors (>10,000 RPM)
- Accepts standard RC radio servo input
The servo originally used a flux gate to sense the position of a magnet embedded in the servo's geared motor shaft. Later versions used a magnetoresistive sensor for position feedback.
- On-board microcontroller
- 1N of force at the actuator arm end
- 180 degrees of absolute position feedback
- 140ms to travel 180 deg, stop to stop
- PID feedback loop with 20kHz PWM motor control
- Coreless motor and planetary gearbox
- Total weight: 2 grams
- Accepts standard RC aircraft servo signals
- 2.9-4.2V input voltage