ServoDriver

The following diagrams are provided and meant to be an easy, do-it-yourself way to control your throttle servo, on the flight-line, independently from the handle.

The components can be gotten at Radio Shack or any other Electronics parts store. In addition to the unit you will need a Deans 3 pin connector (PN 1009) that mounts on the plane in an easy access location..and a 2 pin set for the external voltage supply. You will also notice that each of the diagrams are different and #3 (on the right) is more complicated than #1 (on the far left). So, pick the one that is best suited for your skill level...and have fun.

We are testing these and may be manufacturing one of them, as an optional accessory, in the near future. Until then, this is strictly an experimental project for those who see the benefit and wish to try it. In our application for testing we are using a single 5 pin socket and plug. This utilizes the batteries on board the model and requires only one access attach point. We don't know which one is the best one for our application, as yet....but the parts are cheap enough and it is a rather fun project.


IC1 = LM555 Timer D1 = 1N4148 R1 = 3.3K (3300 ohm, orange-orange-red) R2 = 62K (blue-red-orange) C1 = 220nF (0.22uF) C2 = 100nF (0.1uF) P1 = 5K Potentiometer (Linear)	C1 = LM555 Timer R1 = 2K7 R2 = 68K C1 = 390nF C2 = 100nF C3 = 100nF P1 = 2K7, potentiometer D1 = 1N4148, signal diode	U1 = LM555, NE555 or MC1455 R1 = 10K R2 = 820 ohm R3 = 68K P1 = 1K, potentiometer P2 = 1K, trim-pot C1 = 1µF (monolithic) C2 = 1µF, 16V Q1 = 2N3904, PN100, NTE123AP, or similar
LM555 Timer Pins Pin 1 = Ground (-) Pin 2 = Trigger Pin 3 = Output Pin 4 = Reset Pin 5 = Control Voltage Pin 6 = Threshold Pin 7 = Discharge Pin 8 = Vcc (+)

Additional Notes from Tony van Roon: The circuits above speak for themselves and do not need any more explanation, in my opinion. The Servo control arm can sweep from 1 to 2mSec at approximately 7mA (4.8 volt assumed). PPA is 4 volt at a frame rate of 16 mSec. This is a cheap and worthwhile project. Not only can you check the proper working of your servos you can also check for 'drag' or excessive rubbing when the servos are installed in your aircraft.

Copyright © Tony van Roon

As stated, this circuit was designed by Tony van Roon and is NOT a ScaleMaster design or product (at this time) and it is not associated with Bob Young at SilverTone Electronics. As with all do-it- yourself projects....the craftsmanship and end result is up to the builder..therefore, ScaleMaster can not assume any liability connected
with the use of the circuit with your model aircraft, or its design, and/or quality of the finished unit, unless specifically manufactured by ScaleMaster and sold from this web site, after all tests have been completed.