How to add a potentiometer to the c-brackets?

Lynxmotion Servo Erector Set
1

Hello,
I’m a student working right now on a robot-arm. But as a special requirement I need a potentiometer, or any other position-feedback at each joint.
Can maybe someone give me some advice on how to include one?
Right now i planned to use the normal multi-purpose servo bracket with the c-brackets.

Greetings,
Urm

2

Without any details, I’d suggest hot glue.

3

If you’ve already got a servo at the joint, I’d tap into the pot inside the servo. Search web (or even here for instructions). Adding anything to a C-bracket would be hard, unless you can make your own brackets.

Alan KM6VV

4

Thanks for the feedback.
Intern poti was my first thought also, but the Robot is a university project, where we have to handle with failure in the hardware.
So therefore I need an external one, or more accurate, i need a feedback, which is independent from the servo power.
I suppose, that i can’t use the poti as a feedback during operating the servo and still after disconnecting the servo from the stm? (That’s what our fault is about)
(Problem is, I’m not that good in electronics and my task is just to mechanically build that arm, but with the possibility for external feedback)

5

you could add a fixed gear…
lynxmotion.com/p-794-low-pro … d-ses.aspx
to the C Bracket. and then connect a Pot to the other gear located on the next connecting bracket.
to attach the pot to the gear you could use the internal servo shaft connected to a servo horn and in turn to the gear.?

6

Reading the internal pot is likely the most elegant solution at this time.

7

Thanks for your answers.

@innerbreed: I will have a closer look. Do you know the inner diameters of the gears?

@ All: So, if I get a connection to the internal pot and my assumption is, that there’s now connection from the servo to the stm from the regular connection, I also have to connect vcc and gnd to the pot? So at first I need to recognize the fault and then activate my second connection to read out the pot?

And maybe i can change the requirement so not all of the standard connection is lost, just the pwm signal, then i should be able to read out the pot without adding vcc and gnd?

8

The pot is already powered (assuming you don’t break any connections) - you should only need to connect to the wiper pin and GND to read the analog voltage.