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Opto isolator board

Posted by dastultz 
Opto isolator board
December 08, 2010 02:08PM

I'm building an Arduino-controlled stepper motor driver for a Sherline mill. I'd like to use the optoisolator board to protect my Arduino and laptop. I'd like this:


But the links to the store don't seem to work (one link appears to be bad, the other throws MySQL errors). How can I get this kit? Also, I'm assuming this design is fast enough to accommodate reasonable milling speeds. Any idea how I can get a better idea?


Re: Opto isolator board
December 09, 2010 06:48AM
hello, what kind of arduino a Duemilanove, or a Serial Arduino? i assume maybe incorrectly that the isolator is for the serial arduino. in that case i can not find that page either. the rrrf does sample builds of parts, i don't think they have much of an inventory of anything. (maybe I'm assuming.....)

here is an external link that uses a opto isolated adapter. just found with some Google searching.


it may actually be cheaper if possible to get a usb version of the arduino. it has built in protection for the usb port. do not get a separate usb to serial converter.

there are two known possible points for the serial to hook up to - the Sherline to the arduio, and the pc to the arduino.

if the Sherline mill requires the adapter then the above link i provided would be a possible starting point. anyway hope this helps, if not specify are you hooking up the serial to the Sherline mill controller, or to the PC. A picture or diagram of your setup is worth a thousand words here. someone will eventually help!

good luck!
Re: Opto isolator board
December 09, 2010 09:03AM
I said:
I'd like to use the optoisolator board to protect my Arduino and laptop.

I see that was not clear now, there are in fact two places to insert "protection". I meant between the stepper driver and the Arduino. I'm using the HobbyCNC EZ Driver which has a parallel port connector. So I'll be connecting the Arduino to the DB25 on the EZ Driver to send step/dir signals. It is here that I'd like the optoisolator.

The "Arduino" is currently a Modern Device Bare Bones but I expect to replace it with the latest Arduino. Since I want to isolate the pins, I'm not sure it matters which board I am using.


Re: Opto isolator board
December 10, 2010 04:17AM

the above link is to a pdf of the schematic chip used, and the chip cost from digikey. the chip used in the rrrf part is the HCPL2630.
Re: Opto isolator board
December 10, 2010 02:33PM
Thanks for that. I was hoping to buy a kit, I'm a software guy. A lot to learn here... I guess I could give it a try.

Re: Opto isolator board
December 16, 2010 11:46PM
A previous discussion ( [forums.reprap.org] ) mentioned a $5 "Opto-Isolator Mini Board" [www.futurlec.com] .

It comes with 560 Ohm ballast resistors on the input and 1 KOhm pull-up resistors on the output.
It's advertised as optically coupling 3 V input logic signals to 5 V output logic signals,
but it looks like it will work just as well optically coupling 3V or 5 V input logic signals to 3 V or 5 V or 12 V output logic signals.
Re: Opto isolator board
December 20, 2010 12:36PM
Hi David, thanks for mentioning that. I did run across it myself, but I found some comments on CNCzone that stated the PC817 may be too slow. (It may be fast enough for me but it's nowhere near as fast as the HCPL2630 Zach specifies.) I don't really know how to evaluate it myself. Still it's only $5, so might be worth experimenting with.

Re: Opto isolator board
December 22, 2010 03:52AM
you can also look for "parallel port breakout board with optical inputs".

like this


just searched on Google, this result turned up. don't take my word for it.
Re: Opto isolator board
December 22, 2010 09:16AM
Surprisingly this board does not come up when I do the same search. Anyway, I've seen it before and it may be the best candidate. It wasn't immediately obvious how to buy it. Anyway I've got some HCPL-2630 chips on order so it looks like I'll be building my own.

Thanks for the help.

Re: Opto isolator board
August 06, 2013 10:44AM

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