# Appropriate conversion of myoware sensor output to V

I am currently utilizing the Myoware muscle sensor for a project, It is working perfectly.

I was wondering if anyone knew how I could convert the analog output to a voltage or mV reading. Apparently, the output depends on the power supply, the power supply I selected was 3.3V, I did not adjust the gain and the standard gain is 50 0 kΩ, the input impedance is 110 GΩ, and the supply current is 9mA. To be honest, I am not very well versed in these kinds of circuit calculations, which is why I am asking here, all of the details I listed were directly from their user manual:

https://cdn.sparkfun.com/datasheets/Sensors/Biometric/MyowareUserManualAT-04-001.pdf

Any help would be much appreciated Thanks

Hi,

The Sparkfun spec sheet is outdated; you can find the most recent version on our GitHub repo: https://github.com/AdvancerTechnologies/MyoWare_MuscleSensor/blob/master/Documents/AT-04-001.pdf. The equation to figure out the actual gain of the sensor is on the last page.

To do this you'll need to measure the value of the gain potentiometer first. Take a multimeter on the resistance setting and place a probe on each pin on the two pin side of the potentiometer. It should be around 50 kOhm if you haven't adjusted it yet.

Next, you'll need to convert the ADC value your Arduino outputs from the readAnalog function to Volts. Arduino has example code on how to do this, see ReadAnalogVoltage.

Once you have the voltage and the gain, simply divide the voltage by the gain and you should get the actual mV measured by the sensor.

Cheer, Brian

the input impedance is 110 GΩ,

Pull the other one it has bells on it!