Homemade Electrodes using atmega chip

Projects General Guidance
1

Hi,

I've seen many videos about electrodes as I know there is 2 type, input and output,
input the ones that receive the data and you can register it and do stuffs and
output which flex somehow your body muscles, I'm not even close to know how they exactly work (with the body) so at this point I'd like to know how I can build one (both types) and be safe to use.

Example of electrodes:
Output:

Input:

D.60

2

For muscle sensors, look up Electromyography (EMG). I don't know much about it, but the signals are weak so you'll need an amplifier and probably some filters. This should be generally safe because you are not applying voltage to the body, and even if something goes wrong voltages used in the circuit are low.

As far as stimulating muscles, do some research about how much current is safe and make sure you understand [u]Ohm's Law[/u] and how to limit current to safe levels.

And, note that what's safe for a young healthy person may be dangerous to someone with a heart condition or epilepsy (diagnosed or undiagnosed) or some other unknown condition.

Personally, I wouldn't intentionally run electrical current through my body!

3

Buy them.

Safe?
Connected to what?
To do what?
.

4

One of the electrodes as Output is

Transcutaneous Electrical Nerve Stimulation (TENS)

How do TENS machines work?
Transcutaneous - means through the skin.
Electrical - TENS machines deliver small electrical pulses to the body via electrodes placed on the skin. TENS machines are thought to affect the way pain signals are sent to the brain.
Nerve - pain signals reach the brain via nerves and the spinal cord.
Stimulation - if pain signals can be blocked by the tiny electrical shocks from the TENS machine then the brain will receive fewer signals from the source of the pain.

TENS machines are thought to work in two ways:

On a high pulse rate of 90-130 Hz (the normal method of use), the electrical impulses generated by the TENS machine interfere with and block pain messages sent to the brain. This is due to the gate control theory of pain. This proposes that there is a gate mechanism in the brain and spinal cord nerves (the central nervous system). When the gate is open, pain messages get through to the brain and we feel pain. When the gate is closed, these pain messages are blocked and we do not feel pain. TENS machines are thought to stimulate certain non-pain-carrying nerves and close the gate. In effect, the brain is busy dealing with the messages it receives quickly from the TENS machine, rather than the slower (more painful) pain signals that the body is receiving from elsewhere. It explains why, if you injure yourself, rubbing that area can temporarily reduce the pain.
When the machine is set on a low pulse rate (2-5 Hz) it stimulates the body to make its own pain-easing chemicals called endorphins. These act a bit like morphine to block pain signals.

creating a controllable tens machine
http://forum.arduino.cc/index.php?topic=158242.0

Human Human Interface
https://backyardbrains.com/experiments/humanhumaninterface

5

You purchase the pads from Aliexpress and other places.

Adafruit sells these cool gizmos.

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I know I want to buy one of these myself but I'm still trying to figure out why.

Thanks for the information BillHo. Very interesting.

6

Thanks for the information,
I wanted to build few of them homemade and control them with arduino, looks like a fun project
but too much time consuming and not really safe as I see, I don't want to damage my nerves :smiley: by mistake.
I just wanted a new project getting more experience in my free time experimenting with different stuffs.

Thanks for your time anyway, probably I need to find other things to do in my free time,
D.60