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Topic: Turning something higher voltage on (Read 721 times) previous topic - next topic


How do I use the arduino to turn something on with much higher voltage. For example I have a different power supply, hooked to a 100W motor, with correct voltage and such, how do I use the arduino to turn that on? Please don't hurt on me, I am a noob.

Matthias Welsh

May 04, 2009, 01:54 am Last Edit: May 04, 2009, 01:55 am by TheCodeBenders Reason: 1

that should give you a pretty good sense of how to control it.  If you need to sense what power is going to the load, I highly recommend the HCPL-7520 to get you isolated and operational.  Link for the part is found here: http://octopart.com/info/Avago/HCPL-7520-300E

Also, if you're trying to do control of brushless motors then you're in need of a control method. I highly recommend the http://www.sparkfun.com/commerce/product_info.php?products_id=9107

If you run with that part then I've got a tutorial up on my blog on how to use it for motor control:


I really appreciate this. Thank you, this is exactly what I was looking for.


May 04, 2009, 03:06 am Last Edit: May 04, 2009, 03:16 am by Sean Reason: 1
For controlling 120-240 VAC, 15-60A line current, you have available Solid State Relays which are basically super-sized optocouplers, controllable by 5VDC input.

Input: 4-32vDC
Load: 15A 250VAC



Cheaper than a solid-state relay for switching 120VAC is a Triac, controlled by an optically isolated mini-triac. Something like a Fairchild MOC3032. The datasheet for that part has some good example circuits.


I've used those Optek ones at work to switch a huge solenoid and a motor for a Arcade punching machine, which is on a helluva lot and the people like to use it for hours.

They're real workhorses them things.


Using a Triac and a Opto-coupled Diac trigger definitely would be cheaper. You get experience building an SSR from scratch. Be sure that you have it properly heat-sinked and that everything is properly insulated.Putting a fuse in there isn't a bad idea either.

I usually suggest the SSR because it's easier to implement safely. $12.50 is very inexpensive if you're not experienced with building safe line voltage control circuits.

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