Issue with sig LED using Myoware sensor

Sensors Biometrics
1

Hello all,

I’m working on a project using the Myoware sensor and I’ve encountered an issue I can’t seem to find a fix for. As described in the title, my issue regarding the sig LED is the following :

I’ve only plugged VCC and GND pins (the power LED in on) but no matter how I place the Myoware sensor on my arm or where I put the reference electrode, the SIG LED is either always on, or randomly goes on and off whether I’m contracting my muscle or not.

I attached an image of my arm with the Myoware sensor, can you please tell me if I’m doing something wrong or if it’s an internal problem.

https://drive.google.com/file/d/1q9IGH0 … sp=sharing

https://drive.google.com/file/d/1hbt5st … sp=sharing

Thank you for your help !

2

Are your wires soldered too the Myoware?

3

I didn’t have access to soldering tools because of the confinement in my country so I used simple wires that I twisted to make them hold.

I understand that this might be the cause of the issue, but is it possible that it is caused by something else ?

4

but is it possible that it is caused by something else

Yeah, it’s possible, but the list of possibilities is pretty long. Non soldered connections are the most likely things to cause issues or damage to the board though. Without the wires being securely attached both physically and electrically you run the risk of the board malfunctioning or a loose wire touching a component on the board causing damage.

Also, the SIG LED is a pretty course indicator of activity since it’s either on or off and the analog output on the board is a much better indicator of activity. See the [users guide for more information on connecting the board to an Arduino and the [example code for the Arduino that lets you view the analog output.

One last thing, it’s recommended that you not adjust the potentiometer on the board, it’s easy to break and has already been adjusted at the factory.](MyoWare_MuscleSensor/Example Code/ReadAnalogVoltage/ReadAnalogVoltage.ino at master · AdvancerTechnologies/MyoWare_MuscleSensor · GitHub)](https://cdn.sparkfun.com/assets/a/3/a/f/a/AT-04-001.pdf)

5

Thank you for your response. We will try to solder the wires then and we’ll let you know if it fixed the issue although it won’t be anytime soon because of the current sanitary situation.

It’s a good thing we didn’t touch the potentiometer then !

6

Hello,

Here is the follow up of our issues with the Myoware sensor.

Following your advices, we have soldered our Myoware with our cable shield as you can see in the photos. The day we soldered it, everything worked correctly (the led and the signal were both okay). We are now 2 weeks later, we didn’t change anything and nothing is working.

Our issue is the following :

  • When we plug the Myoware, both leds go on (picture attached below).

  • When moving the Myoware randomly, the red led eventually goes off (and sometimes goes randomly on again).

  • If we barely touch the Myoware in this state, the red led goes on (and sometimes goes off again after a few seconds when we stop touching it).

  • When plugging the jack cable with the electrodes to the Myoware, the red led goes on whether the electrodes are placed on a contracted muscle, uncontracted muscle, or even nothing at all.

The issue is not coming from the sig led, indeed we are having the same problem when reading directly from the sig pin.

Do you thing this issue has something to do with our soldering (the temperature which was between 300 and 350 °C or the way we did it), with our cables, or with the transport of the Myoware which occurred between the two tests (note that everything was in a closed box during transport and we didn’t notice any damage afterwards) ? Could it also be something else which we did not think about ?

Thank you in advance for your response.

Here are the links for the photos :

https://drive.google.com/file/d/1vtL5pr … sp=sharing

https://drive.google.com/file/d/1dctrpH … sp=sharing

https://drive.google.com/file/d/1aJapBS … sp=sharing

https://drive.google.com/file/d/1YTzs80 … sp=sharing

https://drive.google.com/file/d/1SajnVe … sp=sharing

https://drive.google.com/file/d/1RN56Pz … sp=sharing

7

If it worked the day you soldered it, the board should have been fine. It’s possible you have a bad solder joint or lose connection somewhere now, 2 weeks later.

Your LEDs going on and off would indicate a lose or intermittent connection or short somewhere, check all your solder joints and connections between the board and your power source.