Myoware 2.0 sensor sometimes works and sometimes doesn't

Sensors Biometrics
1

Here are the observed phenomena:

  1. When connecting the sensor to the computer for serial port debugging, the ENV light remains constantly on, continuously outputting 4.5V data. I tried using a USB isolator and powering it with the computer battery, but neither worked.
  2. When the sensor is powered separately by a battery pack, it mostly works normally and can detect relatively normal data fluctuations. However, at times, it fails to detect any fluctuations.
  3. When the sensor is connected to my hardware circuit, it sometimes detects data fluctuations, but compared to normal operation, more force is required to achieve the same level of fluctuation. Sometimes it malfunctions, detecting no data fluctuations and consistently outputting data around 0.17V. Other times, the ENV light stays on, continuously outputting data around 4.5V.

I suspect whether the sensor is damaged or if it’s due to significant noise from my hardware circuit?

2

Your sensor’s erratic readings are likely due to noise from your circuit or power issues; isolating it or adding filtering may stabilize its output.

3

I would like to ask, what kind of filter circuit should be added in this situation? Generally speaking, aren’t there usually filter circuits on EMG sensors?

4

It sounds like your setup might benefit from using the REF electrode Getting Started with the MyoWare® 2.0 Muscle Sensor Ecosystem - SparkFun Learn (there’s an additional section way down in the hardware hookup section about it)

5

Intermittent MyoWare 2.0 readings are usually caused by unstable skin-electrode impedance or a floating common-mode reference; ensure all snap connectors are secure and the reference electrode has solid contact. to stabilize the output, implement a software-based Moving Average Filter and verify your power rail stability against the MyoWare 2.0 Hookup Guide to prevent ADC noise.