Remote Switches?

Last night one of the wardens was complaining about getting called a 4 am to switch off the air compressor. A remote switch like this might be a decent solution. Essentially it’s a wifi connected switch, with an internet interface.

https://www.amazon.com/TP-Link-Control-Devices-Anywhere-HS100/dp/B0178IC734/?_encoding=UTF8&psc=1
https://www.amazon.com/Switch-Smart-Wi-Fi-Works-Alexa/dp/B00BB2MMNE

I don’t have much experience with said switches, nor am I sure what the amp draw/voltage requirements are of the compressor but this seems like a possible solution. Switch is for 115V, but no mention of amps. If somebody wants to order it, I’ll handle installation. Fyi they also have remote light switches for when people forget. I realize that’s less of an issue with free electricity.

While there’s some sort of security (probably the usual log/password) they also might be horribly insecure, at which, I guess somebody with a bone to pick could evilly turn the compressor on and off.

That wouldn’t work with our setup amp wise. Technically we could come up with an relay to cut the signal to the contactor to kick the compressor on. The compressor idea has been kicked around a bit and if given the number for workers a simple on off safety led could be put in the fab lab. Then add the remote disconnect you the low pressure switch to kick on the compressor and be able to run that over the a Web based program. Come winter with schedules slowing down I think we could kick ideas around along with a fail safe.

I can build a solid state power switch capable of handling the compressor.
You can also buy relays that will handle 240V / 80A.
-D

I was wondering if there was a low amp signal line for the contactor to have the compressor run. I did a small one in the past with the first robotics stuff however have not looked at ours closely. It would be awesome to put it on a timer with a light indicator in the fab lab with over ride switch.

277V / 90A relay from digikey $35 or so, probably available cheaper elsewhere. DC coil.
-D

Dave -

I’m going to place a mouser order in the next few minutes here. Could I trouble you for a link to a suitable component? Mains AC power is something I know little about.

  • Ry

http://www.mouser.com/ProductDetail/TE-Connectivity-PB/EW80-1A3-B009D00/?qs=sGAEpiMZZMtGt%252bn33CgIP%252bi4G1AlJOKeswNX3Af5Y54%3d

$9. Even better.

-D

Is http://www.mouser.com/ProductDetail/TE-Connectivity-PB/EW80-1A3-B012D02/?qs=sGAEpiMZZMtrMkCunk6IWsSREhYbiUOmkgh05qJDHBE%3d equivalent? The item you linked is out of stock.

Close enough. 12VDC coil vs. 9v coil I think.
-D

If you haven’t clicked “yes” yet, add a cheap H bridge or two:

http://www.mouser.com/ProductDetail/ON-Semiconductor/LV8548MC-AH/?qs=sGAEpiMZZMv0DJfhVcWlK06Hfx1HcUr9tE2iEZfcVGI%3d

http://www.mouser.com/ProductDetail/ON-Semiconductor/LB1948MC-BH/?qs=sGAEpiMZZMv0DJfhVcWlKxMqCO85VILiqZVkWuJrN3c%3d

I just read the datasheet on that relay carefully and it’s a bistable single coil unit so you energize the coil with one polarity to turn it ON and the opposite polarity to turn it OFF.

Worst case, we can put together a drive circuit with a couple of FETs but those h bridge controllers will work and they’re <$2.

-D

http://www.mouser.com/ProductDetail/Diodes-Incorporated/DMHC3025LSD-13/?qs=sGAEpiMZZMutXGli8Ay4kEryqxZo0qh12QOqMGCU6c0%3d

Even cheaper… Less than a buck.
-D

Hell yeah, way to get it going guys!

Can’t we just tap into the on/off switch for the compressor? (the flip lever mounted on the little box on top of the tank) If we don’t want to crack into that box you could make an arduino with a hobby servo to flip the lever.

We could, but I don’t learn new things with that approach. :smiley:

  • Ry

Add a timer to shut off the compressor and purge switch between hours 10:30 pm and 7:00 am? Would solve a lot of problems…

Remember that if you switch power off, it’s 240V, so you’ll need to switch both legs.

There has to be a low amperage signal wire for the contactor from the pressure regulator?

Nope. The pressure regulator actually pushes the contacts closed. The off switch baulks them from actually closing.

Dam :frowning:

The relay solution sounds good.

Set it on a timer. The hook it up to the internet IoT thing is too error prone. If it doesn’t have connectivity to wifi, bluetooth, whatever, it won’t work. Ask the many people who shiver in the cold when their IoT thermostats lose their IP addresses.

I really don’t want to ever utter the phrase “our air compressor lost its wifi connection”.

Lorin