Muscle Sensor V3 readings

Hello guys! Has anyone compared two readings of muscle sensors v3 from arduino before?
I’ve placed the electrodes in the same position for both arms.

Below attached is the screen shot of my readings. I’m using 5v DC power supply to power up both the sensors.

Why does the sensors still have readings when i turned off the power supply with both electrodes off my arms?
And when i on the power supply with both electrodes on my arms with no strength exerted, the readings somehow is different… Is it because of the position of the electrodes?

Please guide me along if anyone knows about this issues! Thanks and cheers!

POWEROFFELECTRODESOFF.png

Hi! How are you powering it with just a 5V supply? The min. required power is +/-3.5V which means you'd need at least a +7V supply.

That data doesn't look like actual data (floating pin noise) which makes me think your sensor isn't setup correctly.

Advancer:
Hi! How are you powering it with just a 5V supply? The min. required power is +/-3.5V which means you'd need at least a +7V supply.

That data doesn't look like actual data (floating pin noise) which makes me think your sensor isn't setup correctly.

Hello! I've now connected it with 7v DC power supply. But it's still the same... When i off the power supply there's still reading coming out by the sensors.. :frowning: How do i get rid of this floating pin noise?

edwardanthony:
Hello! I've now connected it with 7v DC power supply. But it's still the same... When i off the power supply there's still reading coming out by the sensors.. :frowning: How do i get rid of this floating pin noise?

Can you post pictures of your setup? What voltages are you reading at the +Vs and -Vs pins?

Advancer:
Can you post pictures of your setup? What voltages are you reading at the +Vs and -Vs pins?

Hello Advancer! Below attached is the connections. Its abit messy. i short both the Muscle sensors +VS together to the dc power supply +7V, and i short both the GND of muscle sensors to GND Of power supply, and lastly shorting the -VS together to the Negative of the power supply. Is there anything i did wrongly here? And the both grounds of the muscle sensors are connected to the Arduino Uno Gnd and the SIG pin is connection to A0 and A2.

Multimeter shows reading of 14 V from +Vs to -VS. 7 V from +vs to gnd and -vs to gnd. same for both…

edwardanthony:
Hello Advancer! Below attached is the connections. Its abit messy. i short both the Muscle sensors +VS together to the dc power supply +7V, and i short both the GND of muscle sensors to GND Of power supply, and lastly shorting the -VS together to the Negative of the power supply. Is there anything i did wrongly here? And the both grounds of the muscle sensors are connected to the Arduino Uno Gnd and the SIG pin is connection to A0 and A2.

Multimeter shows reading of 14 V from +Vs to -VS. 7 V from +vs to gnd and -vs to gnd. same for both..

You should connect the ground of the power supply to the arduino not the sensors' ground.

You got +7V at -Vs w.r.t. ground?

Oh no sorry my bad, it's only -1.2v..... then where do i connect my sensors ground pin?

Advancer:
You should connect the ground of the power supply to the arduino not the sensors' ground.

You got +7V at -Vs w.r.t. ground?

Hello advancer, there is actually two groud in the muscle senors. One of the ground is with +VS and -VS
The other ground is with SIG. i connected the power supply Negative to the Gnd in the +VS and -VS. as for the GND with the SIG i connected it to the arduino board.

edwardanthony:
Oh no sorry my bad, it's only -1.2v..... then where do i connect my sensors ground pin?

That indicates your power connections aren't setup correctly.

All your ground connections should originate from the same point so you dont accidentally create ground loops. That being said, you should connect the ground pins of both of your sensors to the power supply. You should also connect your arduino's ground pin to the power supply.

edwardanthony:
Hello advancer, there is actually two groud in the muscle senors. One of the ground is with +VS and -VS
The other ground is with SIG. i connected the power supply Negative to the Gnd in the +VS and -VS. as for the GND with the SIG i connected it to the arduino board.

edwardanthony:
Hello advancer, there is actually two groud in the muscle senors. One of the ground is with +VS and -VS
The other ground is with SIG. i connected the power supply Negative to the Gnd in the +VS and -VS. as for the GND with the SIG i connected it to the arduino board.

They are basically the same pin.

Advancer:
They are basically the same pin.

so i basically short the both grounds tgt? And btw, i solved the floating pin issue already. i added a step down resistor in the sig pin.

And i something weird from the readings... i put the electrodes on both arms to measure the strength exerted. Both the readings is some 200-300 difference. What do you think would be the issue? The muscle sensors or the electrodes?

edwardanthony:
so i basically short the both grounds tgt? And btw, i solved the floating pin issue already. i added a step down resistor in the sig pin.

And i something weird from the readings... i put the electrodes on both arms to measure the strength exerted. Both the readings is some 200-300 difference. What do you think would be the issue? The muscle sensors or the electrodes?

Before we move on to another problem, did you fix the issue with your power supply voltage?

Advancer:
Before we move on to another problem, did you fix the issue with your power supply voltage?

Hello advancer, sorry for the late reply. I've checked the connections. It is correct.. But i dont know why when i check using a multimeter, the +VS to gnd is 7V. +VS TO -VS IS 14V but -Vs to GND is -1.34V. Is it suppose to be -7V?

Advancer:
Before we move on to another problem, did you fix the issue with your power supply voltage?

Hi advancer, i dont know if im unlucky or what. The multimeter is faulty. The reading is +7v Vs to gnd. +14v vs to -VS and -7v -vs to gnd… This is correct right? :smiley:

Below attached is the readings from the sensors with the electrode from my left and right arms. the position of the electrodes are the same. But the readings is kind of out of range… what could be the problem? Thanks for your guidance earlier on! :smiley:

edwardanthony:
Hi advancer, i dont know if im unlucky or what. The multimeter is faulty. The reading is +7v Vs to gnd. +14v vs to -VS and -7v -vs to gnd… This is correct right? :smiley:

Below attached is the readings from the sensors with the electrode from my left and right arms. the position of the electrodes are the same. But the readings is kind of out of range… what could be the problem? Thanks for your guidance earlier on! :smiley:

Is that data with muscle flexion?

Advancer:
Is that data with muscle flexion?

Hi good morning, what is muscle flexion? I stick the electrodes according to the pic attached on both arms.

edwardanthony:
Hi good morning, what is muscle flexion? I stick the electrodes according to the pic attached on both arms.

The sensor measures muscle flexion. Muscle flexion is what happens when you flex your muscle.

What is your application? What are you trying to do with the sensors?

Two sensors will not have the exact same output unless you calibrate them to match.

Advancer:
The sensor measures muscle flexion. Muscle flexion is what happens when you flex your muscle.

What is your application? What are you trying to do with the sensors?

Two sensors will not have the exact same output unless you calibrate them to match.

Hello, I'm using the Arduino serial monitor to display the outputs of the muscle sensors. I'm wish to combine the accelerometer sensors with the muscle sensor to make into a project for those people hitting the gym. Maintaining a good posture and at the same time know how much force you exert etc(Not cfm)

But what i wish to know is that, although i know that the readings two muscle sensors would definitely not be the same. But for my case, the measurements is like way off.. by 200 plus. Both electrodes are placed the same position for both arms.

edwardanthony:
Hello, I'm using the Arduino serial monitor to display the outputs of the muscle sensors. I'm wish to combine the accelerometer sensors with the muscle sensor to make into a project for those people hitting the gym. Maintaining a good posture and at the same time know how much force you exert etc(Not cfm)

But what i wish to know is that, although i know that the readings two muscle sensors would definitely not be the same. But for my case, the measurements is like way off.. by 200 plus. Both electrodes are placed the same position for both arms.

I'm not sure what you mean by "way off". Way off when compared to what?

Do you see a difference when you swap out the sensors but keeping the same electrodes on the same arm? (AKA try both sensors with the same set of electrodes).

Can you take a picture of how you're placing the electrodes? Sometimes poor placement can introduce noise that could explain a 200 non-flexed reading.

Are you seeing any response in the reading when you flex your muscle? During muscle flexion the sensor should go well above it's initial values.

I should also point out that it is very common to have a non-zero resting value for the sensor but this is usually around 100 or below.

It sounds like you are not connecting the electrodes properly. there should be 3. and they should all be associated with the muscle you are testing and not each on different muscles. If you want to test right arm-bicep flexion. Two electrodes (one at midpoint of right bicep and the other near the right elbow on the bicep) the 3rd electrode is on a stationary ref point like a bony joint right knee for example. see below for the directions from manuf.

  1. To use this sensor, the user must have three electrodes connected to the subjects body.
  2. The reference electrode should be placed on an inactive section of the body, such as the bony portion of the elbow, shin or forearm. This electrode should be connected to the black or brown cable.
  3. The two other electrodes should be placed along the muscle selected to be measured. The second electrode should be placed along the mid length of the muscle; this electrode should be connected to the red cable.
  4. The last electrode should be placed at the end of the muscle and connected to the blue cable.
  5. Finally, connect pin SIG to an analog input pin of your microcontroller and the GND pin to the ground pin on your microcontroller.