- The camera i have comes mounted on a pan/tilt system with 9g DETRUM servos. This servos have a 90° normal travel and I wanted to modify the “pan” servo to have 180° travel which gives you later an beautiful in-flight side view.
- There are several ways to do this.:
- You can buy programmable servos…
- You can use a servo stretcher, which modifies the signal to the analog servo enabling it to rotate up to 90°+ either direction off of the center (neutral) position…
- You can modify the servo with two 2K ohm resistors…
- Since i have this DETRUM servos already and don’t want to add extra weight to the plane i will use option nr. 3
(This modification don’t work with all servos, some of them have small plastic limits on the gears and/or case and cant move beyond the normal 90° travel )
- First the list of things/tools you will need for this mode
- A 9g servo (in my case a 9g DETRUM servo) You can use HXT900 servos.
- Two 2K ohm resistors (can be found in old broken devices which you may have laying around)
- Soldering iron with a small clean and sharp tip. (the temperature of the soldering iron should not be too high, just enough to melt the solder)
- A peace of soldering wire.
- Here is a diagram of how to find the right resistors using the coloration lines.
- And the schematics
- Now, lets start
This is my 9g Detrum Pan servo.
The first thing i have to do is to disassemble the servo. First remove the 4 screws from the bottom and then gently remove the bottom cap. After that remove the top cover.
This is the bottom of the servo. !!DONT try to remove the two wires which are leading to the motor, the contacts will get to hot and you can destroy the servo!! Just carefully lift the PCB (fold the two wires) until you see the inside of the servo like in the next pic…
The disassembled servo and “lifted” PCB.
Now wee need the soldering iron to remove the black and the red wire.
The resistor “arms” should be cuted to a length of 2mm and folded as shown in the picture above
The first resistor is soldered in place (see schematics, remember the order of the two wires!)…
The second resistor is almost in place, take you self time to position the resistors correctly, there is not a lot of space inside the servo. If you are accurate there will be no problems when assembling.
Both resistors are soldered in place 
And here you have an assembled servo ready for 180 degree travel cheers
- And here a video
thank you.
You are welcome!