My step daughter is Charlene Hoyt. I suspect you’re remembering the right
person with the wrong name 
I remember Char talking about the line bot.
Yeah - she lives near 4th and Main.
Dave Hylands
I am in for 4 if you are still taking orders. Let me know how you would like payment.
Hi all, Joe here, creator of the Mechaduino. It’s great to see this response to the project! If you have any questions or feedback on the design, please let me know!
I also wanted to let you know that we will be launching a small kickstarter for the first round of Mechaduinos in the coming weeks. (But by all means, make your own as well!) If you’d like to stay in the loop on the project, you can follow our hackaday.io page:
Mechaduino | Hackaday.io
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Hey Joe, thanks for dropping by to say hi!
My biggest question is around the form-factor and adaptability to various sizes of motors. I’m primarily interested in using the Mecharduino for Nema 8 (tiny; 20mm square) steppers in the heads of a pick-and-place machine. Is this practical?
The other question I have is with regards to the accuracy and precision. I know when running with microstepping (especially small, that you’d need to otherwise get ~2^14 positions) that you get pretty poor accuracy, precision, and torque. The hackaday page states better than 0.1 degree resolution, which would be the equivalent of ~1/16 microstepping on a 200 step/revolution stepper. How accurate and precise is that 0.1 degree?
If the opportunity still exists, I would like to have 4 of these.
If there is anything I can do to help, parceling out the kits, etc., I would be keen to help.
Hi Rsim,
The boards should work fine with Nema 8 stepper, but they will protrude from the sides. The PCB is about 42mm square so that it will lie flush with a Nema 17 stepper. You will have to make some kind of adapter to go from the Nema 17 bolt pattern down to the Nema 8 bolt pattern, but that shouldn’t be that hard. I have been using 3D printed adapters for mounting the boards to Nema 23 steppers. Lastly, you may have to make a spacer to mount the encoder magnet on so that it is close enough to the AS5047 chip.
So we aren’t really micro stepping with Mechaduino: You could program it to microstep fairly easily, but instead we have been running the motor as a closed loop stepper motor with sinousoidal commutation. This means our resolution is just the resolution of the encoder: 2^14 counts or 0.022 degrees. I’m not sure where Hackaday got that 0.1 degree figure.
Accuracy seems to be better than 0.05 degrees, but we need to do a little more testing to see what the worst case is. Take a look at our discussion of our calibration routine for more details:
-Joe
I would like to get 1 if still possible
Mark
I’m just going to do the pcbs but I would strongly suggest we avoid fracturing the order process. Running things like this is hard, for digikey you upload the spreadsheet with the BoM in it and the part numbers appear on the packages when they arrive. Very error free and low maintenance. Ordering bits and pieces from everyone is hard and error prone.
I believe in supporting local people for local content, resellers I’m less inclined towards. I’d prefer we kicked a few beers to Joe.
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Ok, looks like we’re looking for 40 PCBs, they’ll cost about $CA1 each, I’ll cover the cost for now. Will send them off soon.
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We have 35 units spoken for, and we’ll cut it off there. I’ll update the top post in this thread with details.
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PCBs are away, we will likely get 40 boards, we might get 36, we might get 44.
ETA would be about two weeks.
Exact cost is TBD as there will be a DHL delivery charge, we’re on target to hit $CA1 each.
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Thanks Tom
PCBs have shipped, might be time to start organising the money for the parts buy. I think they will be here this week.
Might also be good to build one and evaluate before people invest 100s?
Going to put this order in on Wednesday after Jarrett and I double check the BOM and any inventory at VHS. Perhaps we’ll just order enough units to get free shipping and I’ll distribute to a few early adopters so we can build and test. If that goes well I can order the remainder.
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Trackable http://www.dhl.com/en/express/tracking.html?AWB=1004098723
ETA is Thursday might be Friday if they muck up the taxes as usual.
Thanks Tom!
I volunteer as tribute (for beta testing).
Strangely enough I’ve actually used those hall effect sensor chips before, they are fantastic.
As mentioned to Luke, I sourced my diametric magnet from here: D42DIA - Neodymium Disc Magnet | K&J Magnetics
If anyone has a cheaper supplier for diametric (not axial) neodynium magics let us know.
hey @lukecyca, please let me know how and when you’d like me to send money for my two - paypal/interac/etc?