Perry_S
Resolved by DJ Sures!
I tried posting this as a question but could not get that to work so plz move this over if needed.
I have searched the site and help files and not found an answer, perhaps someone here can help if there is an existing script or plugin that does what I need. Is there a way that I can use a continuous rotation servo with an external potentiometer to act as a standard servo? For instance, on my inmoov I had to strip the pot and limiting pin from a standard servo and install the pot on the shoulder such that the servo would make multiple revolutions through a gearbox while the arm rotated 90 degrees. That's a lot of work.
To be specific, I do not want to use a motor to do this but rather a CR servo. Not sure how the speed would be handled and imagine the pot would have to be read as an analog signal requiring 2 pins to run it but I can accept that. It would allow me to use different gearbox/belt drive/ planetary concepts for multiple revolutions using basic servo commands.
Thanks!
Great news about the questions function being fixed. Website maintenance is a lifelong task.
I have found a servo that is easier for me to pull the pot from so I will work with those for now. For the sake of this discussion, CR servos do have a decoder in them. I am just probably using the wrong term. I meant that they take a standard 1520 uS PWM servo signal and convert that to a signal that instructs the onboard ESC to create an analog +/- voltage for the motor inside. That is the decoding function I was talking about.
Regardless, thanks for the discussion.
Marked as 'answered'
Oh yes you’re correct - that’s an interpreter between a pwm signal and output motor. Sometimes they are digital (microcontroller) or analog circuitry.
which servo did you find that works? It’ll be good to know for some of my projects. I know Jeremie is starting to build some interesting stuff at home too
I just received a batch of these servos. Nothing special about them from a performance standpoint as they are only about $15. Just a clone servo.
The reason I like them is because the pot and controller board are connected and both come out without desoldering. Just kinda tug it out gently. This way I can mount the pot and servo electronics right at the joint, the servo is just a motorized gearbox with no internal electronics. If you use a gear or two at the pot located in the final axis you can now tune your servo to operate over any range. For instance if you start with a 90 deg servo and put a 1:2 reduction on the pot you now have a 45 deg servo. If you use a 2:1 reduction it is now a 180 deg servo. A 4:1 reduction would give you a 360 deg servo and so on. There is still a metal limiting pin that needs to be pulled though and that is a bit tough at times.
Who knows, maybe the EZRobot hidef servos look like this on the inside? I don't have one but I bet you might
I actually don't - but jeremie should. I think he mentioned taking the weekend off to do something so he might not see this right away. He'll chime in
Here is my 'deconstructed' servo. It will serve the purpose of what I was initially trying to do. On a standard modified inmoov servo the electronics stay in the servo so there are wires coming out for the serv and for the newly relocated pot. THis method only has one set of wires leaving the servo so it is much easier for cable routing. An added benefit is that the electronics now have better cooling so maybe it won't burn out as easily.
Interesting that the pot is directly mounted to the PCB on that servo. I've rarely seen that.
The EZ-Robot HDD servos have some wires connected from the PCB to the pot. The pot can simply be removed by popping of the output gear and then removing the retaining screw. If there's any silicon or hot glue around the pot you'd just have to use a bit of isopropyl alcohol to loosen it up and remove it.
Jer, the question is do ezrobot continuous rotation servos have a pot