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As Carl said, there are lots of ways to do level shifting, and lots of finished modules on the market. All of them need a 5V supply, and I don’t think that you can get that from the speed controller. So you have to create it yourself, using an 7805 or similar.
I don’t know the speed controller circuit; because it does not accept any lower values than 3.5V keeps me thinking that it either feeds this directly to a power FET or an optocoupler. In both cases, it would be better to use a voltage in the upper half of the allowed range (8-12V). I’d use something like this (no guarantee as usual, and if you are not familiar with soldering and measuring the circuit, you better buy a finished module)
Alhaddar
Have a good look thru thisThis package look VERY similar to what you purchased.
One can imply from this that tinyG will drive the controller even though it is slightly below input range spec.By the way, do you have a separate DC supply for your spindle?
HIGHLY recommended. You will get better motor performance runing at higher voltage, plus spindle likely a source of electrical noise you don’t need connected to your tinyGCarl, for schematics I would only recommend Eagle. The freeware version is already very capable, lots of tutorials online, many freeware designs are made with Eagle, every PCB house accepts Eagle files, many people use it. I drew the schematic above in LTSpice for quick simulation, but it has an abysmal user interface.
Yeah, there are several versions of it around. I read somewhere that when jumpered for the pot, it uses a simple 555 circuit to produce a home-made PWM signal and drives a FET with that.
Q1 in my schematic inverts the input signal, so it seemed safer to me to add a second stage to invert it back.
It would definitely be much easier if we knew the actual circuitry of the board. I was already tempted to order one just out of curiosity (but it takes 3-4 weeks from china to me). Found another bigger photo of one version: http://i.bosity.com/office_cache/274/14008974/4840000011395984469_14008974_6_image.jpg”Guys
After looking at Alhadar’s spindle package and a bit of research, I realized I needed one too; my dewalt 660; beefy, fast, is too much RPM for engarving lettering on acrylic (it is overheating the material).
So I purchased a spindle and a controller like Alhadar’s from Amazon.Comes with Zero documentation.
I found this from a different seller
, which is consistent with the Inventables link I posted a couple days ago.As we suspected, the PWM input is connected to an Orient 817C opto-isolator, PWM+ to the anode thru a 600 ohm resistor, PWM- to cathode.
Note that the jumper must be properly positioned to use the PWM input rather than the POT.It will be a week or so before I can actually test it with my tinyG. I’ll be trying first the direct connection – similar to what the Inventables link displays.
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