We are using a Dark 12" actuator from AndyMark this year on the robot. Question on the wire connection to the potentiometer. What had other teams used for a connector to connect signal wire to the potentiometer?
We went through a whole ton of those potentiometers when we used darts in 2017. They kept breaking at the worst possible moments. We took a whole bunch apart to figure out what was going wrong. I cant remember what we concluded but we ended up deciding that the best solution was just to put an encoder on the cim/775 we had driving it and to use a hall effect sensor to zero it every match.
Heres a couple of the darts we broke. I think in the end we had about 5 that we went through.
TLDR. If I were to do it again i would avoid the pots in the first place.
When we used a dart last, we just mounted a string potentiometer nearby.
When you mounted them, y’all were sure to make sure they were turned a bit so they wouldn’t “bottom” out on the endstops, right? Otherwise, I don’t really know what y’all could have been doing to break them.
3468 used two darts last year with the included precision pots to raise and lower our reverse double-four-bar lift. We just cut the male end off a couple PWM Cables, striped and soldered the wires to the tabs, using heat-shrink to insulate them. So from bottom to top (note that the pins are not in order 1,2,3 check the datasheet) we wired White/Yellow to pin 2, Red to pin 1, and Black/Brown to pin 3. This allowed us to plug straight into the RoboRIO analog ports. Likewise, we could have wired it into a Talon or Spark MAX data port as an analog input using a breakout.
We used the two that came with the darts the whole season without issue.
I wasn’t super involved in the DART’s but that sounds like something we tried. I’ll try to remember what the exact failure mode was but it was something relatively counter intuitive if my memory serves me right.
According to AndyMark’s DART page:
- The potentiometer will turn 8.76 times during a 12 inch travel
This means there is a fair amount of tolerance to ensure that the 10-turn potentiometer does not hit the end of the stroke either direction, but there’s also plenty of room to get it wrong. 3946 worked with 9+ turns of some 10 turn pots in 2015 for our electric tape measure sensor, and they worked great until someone disassembled and put them back together in the wrong position.
Back to the original question proposed by @WStech …
Turret style connectors like the ones on that potentiometer are meant to be soldered to. You take your wire, give it a wrap or two around the post, and solder the ball of wire you just made. Just don’t leave the heat on too long or you risk melting the casing.
Thanks for all the suggestions. Late last night I took the actuators apart to reset the potentiometer thinking the students may not have read that part of the instructions clearly. Good thing I checked.
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