February 6, 2014
about 9 months ago
So I was able to get the sensor up and running (one of them). Couple lessons -
1st - Electrode place is SUPER important. I think the manufacturer could do a better job in the instructions of demonstrating/illustrating this. Once I got the electrodes in a good place, I was able to get a read out of it.
2nd - Push the electrode 3.5mm connector in really well. With the low profile on the board, its a bit of a hassle to get a good grip and push in, but there should be no silver of the connector showing. This will muck things up alot
3rd - It outputs a DC signal. This tripped me up a lot when I was trying to get readings. On AC, you will get minimal reads off it, switch over to DC, and you should get a nice signal response. (Hehe, read datasheets, its rectified!)
In order to do testing, I hooked it up, and put a multimeter on there to test the output. Along with PraTap123, I was able to get a read, but it definitely doesn’t get up to +Vs, regardless of how much I tweak the pot, which is fine for now. I’m gonna get in touch with Advancer and see if we can track down the particular issue.
If you have issues, don’t give up! It does take some working on, but they do work! Follow this link (http://www.advancertechnologies.com/p/tutorials.html) to the manufacturer website for nice tutorials and a demo that shows the sensor working. Note the electrode placement in the tutorial. This was my 1st indication that placement is more important than first thought
about a year ago
This is the same issue I am having. I went back and did some more testing - I havevoltages at every step except for the output so far. The power supply leads read ~18 volts, and I can get readings at the 3.5mm connector (you can read a voltage, I was seeing inbetween 380-60 mV on two of the four leads). So the unit gets power, the electrodes are providing signal, but there is just no output. I too followed the tutorial provided here, and there is just no output. Sometimes, if I jiggle things just right, I can get some varying voltage out of the outputs, but nothing more than 300 mV, which if Im not mistaken, is WAY low. (I was mistaken in my 1st post about expected outputs). Its almost as if the op-amps are in backwards or something.
Sparkfun, if you could look into this, it would be great. I’m really looking forward to using these and making stuff, all I need is functional boards and Im off!
I have purchased two of these sensors, but am having difficulty getting them to output a reading. I have both wired up individually as indicated in the user manual, and hooked them both up to a Arduino Uno, using the wiring diagram provided. When I run the example code provided on this page, I don’t get any readout from the pin that they are connected to. As all pins are declared in the code, all of them provide a baseline reading, which don’t change (and shouldn’t if there is no sensor on those pins). However, even the pin that I do connect to the sensors only read a baseline value that doesn’t change when I move the muscle. I checked that there is signal coming out of the sensor, and indeed there is. Using the gain, I can modulate the magnitude of the signal, but it doesn’t respond to any muscle movements - i.e. the signal voltage stays the same regardless of muscle movement, but DOES change when the gain is adjusted. I have seen readings on my multimeter of as low as 61 mV to as high as 399 mV (which I believe is expected when using two 9V batteries).
So, what am I doing wrong? Are the sensors really sensitive to location? Is there a trick to how they should be placed? Is there a way to test for dead functionality? Any assistance that someone could provide in figuring this out would be greatly appreciated. Thanks in advance.
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