With Shanghai locking down ports, in might be a while until motors are available.
Im sure the power supply and the drivers can be sourced else where, but has anyone had any success sourcing the stepper motors?
Would yall recommend I just place the order as my kit has not arrived yet and wait until they are in stock or seek alternative motors in amazon with the same specs.
Greatly appreciate any input or advice given.
I’m in the same boat, and they don’t expect to be able to ship until the end of May at the earliest. They do actually have the AR3 motor kits in stock, though. It looks like there wouldn’t be a loss of functionality if the AR3 kit/CUI encoders were used, though it would be a smidge more expensive ($40-50).
The wiring is a little bit different and the CUI encoders need more than 3.3V. If I ran “AR4_teensy41_CUI_enc_sketch” to account for the encoder pulse differences, followed the wiring diagram of the AR3 (other than switching the limit switches to 3.3V) into the Teensy 4.1, and supplied the CUI encoders with 5V, would I need to do anything else?
in the ar3 upgrade sheet
" The main issue we are dealing with here is that the AR3
uses 5v for the limit switches and returns 5v to the Teensy
– The best way to upgrade to the Teensy 4.1 board is to
run 3.3v out to robot base and then rewire all the limit
switches to the 3.3v."
I also ordered the ar3 motors and placed the order for the encoders and, my questions would be, if im using the ar3 steps for the encoders should I use the steps from the ar4 or continue with the ar3 as I ordered the ar4 complete kit and wiring is different.
will be documenting everything when motors arrive also just in case anyone is in the same steps as I am.
Appreciate the feedback.
@thomas-f I just changed my order for AR4 steppers kit to AR3 steppers kit, I was lucky to be able to buy it from Germany, and together with the CUI encoders all was working actually cheaper for me. I am happy with the electrical changes necessary on supplying the CUI encoders, there's no rocket science there, and Chris did a terrific job explaining how to connect these. One question though, I might have to experiment with, the settings for the CUI encoders are for 512 steps for revolution, but might well be set for 1000 steps per revolution - that would keep them compatible with the AR4 encoders. The limitation of 512 might be due to the transmission wires, as I don't believe that the 7500 RPM acceptable for 1000 steps per revolution, compared to 15000 RPM for 512 steps per revolution would make any difference.
@thomas-f The CUI encoders have push-pull outputs, the high level voltage is actually higher than 3.3V - it could be very close to 5V. Teensy v4.1 is not 5V tolerant, so level shifters should be added to the phase signals (A and B, it looks like the index signal X is not used). I will post here the schematics after I will test the adapters, but this might take some time, as I don't even have the kit here. Mot likely a open drain buffer with pull up to 3.3V will work, but we'll see.
@gio-s I am in the same boat, I don't have yet the electrical package. To me, the re-routing of the limit switches to 3.3V was obvious, but thank you for the reference. The issue I am describing, with the encoders running on higher voltage than 3.3V is a bit subtle, and might not bite back immediately, but sending signals (A & B from each encoder) at 5V to the 3.3 inputs of Teensy v4.1 might damage the board in time (and, sometimes, immediately). That's why I will not even try to connect directly the CUI encoders' outputs to Teensy, but just through a level shifting circuit, like in below image (that has to be repeated for each of the encoders' outputs, 12 in total, two 74LS07 ICs will suffice):
Please pay attention, the buffer used here as level shifter has to be open-collector, or open-drain. Other types of level shifters are available, but this would be one of the cheapest and most available. I will post the whole schematics and assembly when I will have it ready. Doing this, still needs adaptation for the limit switches, either supply them from 3.3V (the simplest and cheapest way), or add another level shifter for each limit switch.
Regarding the steps to follow, you need to understand exactly what each steps means, Chris was very careful to describe everything in detail, but when combining the AR3 kit with the AR4 controller (aka Teensy), things might become a bit hairy if you don't know what you are doing. I might return the favor that Chris done to all of us, and create the step-by-step instructions on how to setup the combined setup (AR3 electrical with Teensy 4.1) - but this will take some time, unfortunately.
@midnightoilburner followed, will gladly be looking forward to your build and I will follow steps for the ar3 (3d printed) and save the aluminum pieces for the ar4 when the motors are available, save me the trouble of doing extra work but greatly appreciate the advice.
I am currently working on contacting other companies to see if they can provide a kit/bundle with the same specs as the AR4 kit. If I come across anything promising, I will be contacting Chris and I can update this post. Bear in mind that the new kits will most likely cost more.
