Model servos are used for controlling mechanical components, especially in RC models - park / indoor flyers made of polystyrene, small cars - for controlling flaps, turning car wheels or rotating accessories of model railways.
In the case of model railways, they offer, together with the corresponding decoder, a smooth changeover of switch languages, mechanical signals or barriers. This type of servo is one of the most commonly used for these applications. Most decoders, brackets, etc. count on its use. A suitable replacement for the more expensive HXT900 variant, which is dimensionally identical. It differs mainly in the durability of the plastic housing, which will be appreciated more by flight modellers.
Servo dimensions:
| Weight(g) |
9 |
| A(mm) |
30 |
| B(mm) |
23 |
| C(mm) |
29 |
| D(mm) |
12 |
| E(mm) |
33 |
| F(mm) |
16 |
Servo signal wiring:
| wire |
signal |
| orange |
control signal |
| red |
power supply |
| brown |
ground |
!! The servo is not suitable for use in helicopter or large aircraft models !!!
Model servos are normally controlled by a signal from an RC receiver or other decoder that generates pulses of 1 to 2 ms in length and 50 Hz frequency. The duration of the pulse controls the angle of rotation of the servo - see picture - the center position corresponds to a pulse of 1.5 ms.
The servo itself consists of a DC motor, a set of gears and control electronics that ensure the correct adjustment of the servo lever according to the control signal. If you do not want to use this control, the built-in electronics (including the feedback potentiometer located on the axis of the lever) can be removed and only the mechanical part (housing with gears) and the motor can be used from the servo. Caution, this operation means interference with the product and loss of warranty (!).
Different types of decoders can be found for controlling and rebuilding the turnouts. As an example, we refer to the instructions for building a servo decoder with an Atmel processor. Unfortunately, it is in German and English only.
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