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Measure multiple currents and voltages

PostPosted: Fri Aug 18, 2017 6:25 pm
by eduperez
I am planning to recycle an ATX power supply into a bench power supply; instead of using a LED / LCD to display the voltage and current on each line, I was thinking to use a ESP8266, and send that information to a tablet, probably using web sockets.

My question is how can I measure several currents and voltages using a single ESP8266. I have been pondering several methods, but I am wondering if there is something more efficient. Perhaps there are modules that can make the measurement and send the results over I2C / SPI, perhaps I can easily multiplex the ADC and use analog modules, ...

Re: Measure multiple currents and voltages

PostPosted: Fri Aug 18, 2017 6:40 pm
by QuickFix
Measuring voltage (and current) should be fairly easy with an I2C module like this:
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Re: Measure multiple currents and voltages

PostPosted: Fri Aug 18, 2017 8:49 pm
by rudy
I have used the INA219 modules an I really like them. If you need to measure higher currents then you need to use a lower resistance shunt.

I have also used ACS758LCB-100B and similar devices in a new product where I need to measure up to 100 amps. It is not as convenient since it requires the use of an a/d converter but it allowed us to take measurements at a precise point in a pwm waveform in a motor speed control application. This sensor's output is noisy.

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Re: Measure multiple currents and voltages

PostPosted: Sat Aug 19, 2017 8:21 am
by trackerj
For my SmartMON v2.7 Board I was also using with great success the INA219 IC. Combined with a high quality Shunt resistor you can have a very nice and stable solution for it. A good quality shunt resistor might be quite expensive but believe me, will worth every penny!

You can find a lot of details, from hardware to software in the related Youtube Videos and Articles :

- Part1 - General view
- Part2 - Real Time Clock driver example
- Part3 - Power Monitor software example
- Part4 - Real World example with Thinkspeak data upload

Happy breasboarding,
TJ.