Somewhere I read that it could be unreliable to control stepper motors directly from the raspberry pi. I think it was related to 3d printers and it was referring to the nema 17 motors. I don’t have the technical knowledge to comprehend all the reasons why but I did understand it could fry the board. Also, I was not sure if the OF code would drive the motors without including an arduino chip.
With that in mind I purchased the Arduino Nano 28BYJ-48-5V Stepper Motor Shield and power it through the USB port. Overall it runs fine but I feel it lost some torque.
Hello Daniel,
Like you could see in the pictures of my microscope, I used
2 power supplies: one for the Pi, and one for the motors and LED,
because I wanted to play on the safe side.
As I could understand, the Pi is sensitive to voltage fluctuations,
resulting in “bad” behavior.
According to the instructions of the openflexure.org, the Nano will
work with the software intended for the Sangaboard.
Regarding the Hat for the Pi, according to the technical data,
the Hat can be powered separately from the Pi.
Although it would be an elegant solution, it is unknown if the software
would be compatible with the Pi and the Pi Hat.
In consultation with Dr. Richard Bowman, he told me that he is planning
to power everything with one power supply bearing multiple USB outlets,
capable of powering several microscopes at once. (externally to the microscopes)
I actually endorsed the idea, and acquired a 65 Watts power supply with
two USB outlets capable of supplying 5 volts / 3 Amps per outlet.
It will be housed in a modified power supply enclosure capable of being
interchangeable with a Battery enclosure, as soon as I finish the designs.
I’ll send you photos when I have something to show…
Keeping in mind that not everyone is capable of soldering, and that we
are dealing with voltages of 120V / 220 V, (as Richard pointed out) I’m going
to use a power cord, and discard the ON/OFF button and the computer
outlet to power the unit. In terms of safety, it will be more “palatable”,
but the unit will have a “tail” attached permanently.
If I will ever finish/edit a video of what I’m doing, I will post it
on YouTube to help (or confuse) someone starting this interesting project.
Regards,
Luis B.
Can try with something like this? I have one like this powering the Raspberry Pi of my Voron 3d printer
MEAN WELL RS-15-5 AC to DC Power Supply Single Output, 5V 3 Amp 15W https://a.co/d/icAO8UK
Hi Daniel,
It looks like a very viable solution, and two of those would do the trick.
(one for the Pi, and one for the motors)
3 Amps is the recommended amperage to power the Pi 4,
and it would also be enough for the motors. One power supply
to power both might not be enough; the Pi hates low power.
By the looks of them, they will need at least to be provided with some
passive convection cooling. Overheating them will shorten their lifespan.
I would recommend to print a protector to cover the terminals.
I’m going to try the 65 Watts wall power supply that I bought,
that has 3 USB outlets, with 5.1V 3A each.
I’m trying to set up a system that will minimize the exposure
to high voltage, (120/240VAC) by using an extension cord,
thus avoiding stripping wire and connecting to terminals, or soldering.
In my case, the USB outlets will also simplify to disconnect the wiring
from the microscope, and connect them to the battery power banks,
that also have 5.1V USB outlets.
I’ll send a photo as soon as I finish to design and print the new enclosure.
Cheers,
Luis B.
Hello Luis,
I would really appreciate if you’ll be kind enough to send me the file of the body with the pi, arduino and motor drivers.
Regards,
Miranda
My Pleasure Miranda,
Send Photos
Luis
Hello Miranda,
Att. are the Fusion 360 Files
This are the last versions. Feel free to improve them.
The Drivers Shelf stand (Top and Bottom) were made in
two pieces and glued together - it was easier to print them that way.
The top was modified, because when I put everything together, the
objective was hitting the Driver Board.
I also modified the Nano Board base; it was easier to print separately,
The base has an “L” shaped on the interior wall, to assist gluing the
Nano Board Base.
The files are at the bottom of your email, below the photo.
I hope this helps.
Regards,
Luis
(Attachment Openflexure Stand no Openings Modified v14.f3d is missing)
(Attachment Openflex Step Motor Driver Shelf v5.f3d is missing)
(Attachment Driver Shelf Bottom v3.f3d is missing)
(Attachment OpenFlexure Arduino Nano Support v8.f3d is missing)
