I have a question regarding one of the encoders of the motors delivered with the A4WD3 (tracked). I have hooked up all for encoders and tested that the values that come out of them make sense (within the 10% tolerance in motor RPM given in the specs). It does for 3 of them, the encoders return about +/- 10% the same value for the same motor command (sabertooth in simplified mode). The numbers also match with the number of revolutions. But one encoder does not, it returns 1about /4 of the value which the others do. However, the motor turns at about the same speed as the others (can be visually verified).
The motors themselves don’t have specs written on them, so I presume they are all the same, and have 1:51 gear ratio. Did you experience this before?
Hi, thanks for linking this to my other post. I only opened this as a new topic because it’s a different issue - this one is about an encoder which seems to be off, the other post was about whether using 2 sabertooths might be better.
Hi @JenJen was on the fence, but because it’s all about the same A4WD3 tracekd robot, and specifically the motors & motor controller(s), it seemed best to have it all in one thread, especially for searches and other users who have similar questions / issues.
Ok, no problem. I didn’t get a response to this question (about the encoder) in the other topic just yet. But there might be one soon. I already marked the other one as solved, so it could look like no response is needed there any more… we’ll see
Have a lovely weekend!
Can you connect the problematic encoder to one of the other three places to see if it’s a question of code, wiring or PCB? If three work, and the one which does not work in the same conditions / physical connection as one of the functional ones, the issue is likely specific to that encoder PCB.
If it does work correctly however, then it might be an issue with what it connects to (the pins perhaps, total current draw etc.).
If it doesn’t work, take a careful look at the encoder PCB, the connections and the wire to see if you can spot something that might not be right and if so, include a photo here for us to take a look at.
I already did that, it’s the first thing I tried actually. It prints the same odd values.
I am away the coming week and don’t have the motor with me to take photos. When I return I will take some and post them here. I did have a visual check, and nothing looked odd at first glance, but I didn’t take the motor out of the robot base. So I’ll do that and have a closer examination, and let you know. Probably by Friday or Saturday.
Yes, it’s strange, but I’ll take the motor out when I’m back and do a closer examination with pictures. Maybe you can spot something. I’ll let you know in this thread when I have done it. Thanks
Hello, so I got back now and had a proper look at the encoder, after taking the motor out. Nothing looks odd to me… what do you think, you notice something off?
It does have solder on the back, and for the others it looks similar, for 2 of them the solder comes through the hole though. But you’re right, it does seem a bit flimsy. I can top up the solder and see if that changes?
Though I’d guess it’s either signal or no signal, or random skipping of signals and hence random noise due to the distortion of the signal, but a consistent drop to about 1/4 seems odd… What do you think?
The main issue we have had with these gear motors has been the magnet breaking in transit (which we corrected). Otherwise if there’s no physical damage, these have been very reliable. If there’s electrical contact despite no solder coming through, then it should be ok. Open to ideas, but if it really does seem specific to that motor, and you have tried it in the place of one of the other three and it still doesn’t work, we can proceed with an exchange.
I have plugged it into the connections of the other three, and the behavior was consistent. So it’s definitely nothing in the wiring. I am happy to try more solder, if that doesn’t exclude proceeding with the exchange in case this doesn’t fix the problem?
I just added a bit of solder to the front as well, but still the same issue. That would have been our guess too, but it was worth a try… would it be possible to proceed with an exchange?
Searching using the email you used to sign up on the forum doesn’t show any orders for this robot / motor, so can you send an email to [email protected] with your order number and a link to this thread (the URL)?
