I would like to build an AC current sensor to detect if my treadmill is being used (the treadmill would plug into my device, which is plugged into the wall). I would then like my device to tell me what the AC current is (so I can see if the treadmill is on) and transmit this info via Wifi.

What kind of components would I need, and at what cost? I am open to using the Arduino, but if it can be built without one that's preferable.


Non-Invasive Current Sensor - 30A <== This thing would probably work well. It doesn't need to connect to your treadmill directly. It uses inductance to detect current flow. You don't have to use an Arduino, but it would be one of the easiest ways.

There are many wireless things you could do: XBee, WiFi, Bluetooth, etc. All of them are somewhat expensive $80-200 range. Logging data to a MicroSD might be an easier solution.

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  • \$\begingroup\$ Thanks! Would this Wifi SOC work? It's only $26. semiconductorstore.com/cart/pc/viewPrd.asp?idproduct=47831 \$\endgroup\$ – user1137778 Dec 13 '12 at 6:17
  • \$\begingroup\$ If it can read an analog sensor then I don't see why not... It looks like it has 1 ADC on it and there seems to be good documentation. Have fun! \$\endgroup\$ – Hair_of_the_Dog Dec 13 '12 at 12:22
  • \$\begingroup\$ Thanks. I'm really new to DIY electronics - do you have any tips on where I can find a schematic or circuit design? How would I connect the current sensor to the wifi chip? The wifi chip datasheet says it has an "ADC port" - does this mean I need to get the ADC chip separately? \$\endgroup\$ – user1137778 Dec 14 '12 at 9:25
  • \$\begingroup\$ If you are looking for a schematic or an example of how to use the current sensor I'd stick with the arduino examples. They are the easiest to understand and have the most documented examples. sparkfun.com/products/11005 + sparkfun.com/products/11021 + sparkfun.com/products/9954 + openenergymonitor.org/emon/node/58 = a possible solution with good documentation. The ADC port on the wifi module would do the "Analog to Digital Conversion" for you, but I can't imagine it will be easy for you based on your current experience level. \$\endgroup\$ – Hair_of_the_Dog Dec 14 '12 at 17:44
  • \$\begingroup\$ Thanks - I've heeded your advice and am using the Arduino. Can I clamp the current sensor directly to the treadmill power plug, or do I have to separate the + and -? \$\endgroup\$ – user1137778 Dec 22 '12 at 3:05

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