Major Servo Manufacturers
There are different servo manufacturers in the market. Although all of them use the same servo principle, there are few changes they generally incorporate to differentiate their products from others.
Four major players in servo (or radio) world are:
- JR Radios
In the following section we will see how servos from each manufacturer differ from each other.
As mentioned before, servos have three wires coming out. One for power, one for ground and one for control (input signal). Depending on the manufacturer, color of each wire can be one of the following. If you are not sure, refer product datasheet.
Ground: Black, Brown
Signal: Yellow, White, Orange, Gray… well, can be any color
If you are sure that you have identified the wire colors, the wiring order may not be a big challenge. Most manufacturers follow Signal, Power and Ground Scheme; i.e.
There might be exceptions in the above wiring order. For example, servos from Airtronics reverse the power and ground connections. Their wiring order is Power, Ground and Signal. As mentioned, always check datasheet before designing.
Hold your breath; we are not yet out of the manufacturer’s war and the difference in their designs. Futaba connectors generally have an extra flange which Hitec servos do not. This extra flange is there to avoid plugging the connector incorrectly. (I have never fried a servo by plugging it incorrectly; so this flange is just there). But be informed that you cannot plug Airtronics (or similar) servo to Hitec or Futaba compatible products as the wiring is different and you will definitely see fumes. If need be, open the servo, desolder wires, swap them and solder again (at your own risk).
Servo output spline
If you are still holding your breath, then this is the last major difference between servos of different manufacturers, the Spline. Spline is where servo horns are connected. Spline in a Hitec servo has 24 teeth while Futaba servos have 25 teeth. Why? Just so that the servo horns (or is it arms?) manufactured for one servo will (or should) not work on the other servo.
The differences mentioned above depict characteristics of standard servos manufactured by listed four major manufacturers. Other variants are also available from the same manufacturer with different specifications. Not sure? Read the datash…!
Irrespective of manufacturer, most servos do not have a full 360° rotation. Their rotation is limited to 90°, 120°, and 180° only. If you need full 360°, you either need to modify (hack) the servo, or purchase an already modified servo from the manufacturer (which generally costs more).