add lab 8 readme

lab8/README.md

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+# Lab 8: Detecting and controlling hand movements
+
+### Introduction
+In this lab, we will try recording EMG signals from various muscles, and then try to stimulate these muscles with a TENS device.
+
+### Recording EMG
+
+We will restrict ourselves to the OpenBCI GUI to visualize EMG signals, as they are clearly visible without much processing.
+
+To setup the Ganglion to record EMG, you can then follow the [Ganglion getting started guide](http://docs.openbci.com/Tutorials/02-Ganglion_Getting%20Started_Guide#ganglion-getting-started-guide-connect-for-emg) .
+
+- Try connecting it to your arm at first, following the tutorial
+- Try other areas! Can you detect biceps? Fingers? Leg? Feet? 
+
+### Stimulation with TENS
+
+For this lab, we'll be using the [TENS 3000](https://www.tenspros.com/tens-3000-analogue-tens-unit-dt3002.html) .
+
+This comes with a rather instructive [manual](https://www.tenspros.com/assets/images/manuals/TENS-3000-dt3002-Manual.pdf), which I suggest skim through.
+
+Here are some key points for us:
+- This TENS is mainly intended for relieving pain, but it's powerful enough to cause muscle contraction
+- Generally you want the mode set to N ("Normal"). B ("Burst") and M ("modulation") are special modes that fix or vary the pulse rate. (See [page](https://www.tenspros.com/tens-3000-analogue-tens-unit-dt3002.html) for details.)
+- There are 3 main settings to control:
+    - Pulse amplitude, controlled by dial on the top (0-40V, dial shows 0-8). This is the main control of stimulus intensity.
+    - Pulse width, from 30 to 260 μs. This also affects stimulus intensity, but not as much as pulse amplitude
+    - Pulse rate, 2-150 Hz. This affects how often you get stimulated. 
+
+Warnings:
+- DO NOT put electrodes on the front of the neck, around the heart, or on the head (back of neck is okay)
+- DO NOT put one electrode on front, and one on back of body, as this could pass current through the body
+- DO NOT use this if you have a cardiac pacemaker
+
+Using the device:
+- When using the device, make sure to have it off (pulse amplitude at 0) before connecting. 
+- There are 2 electrodes, that you place across the muscle you want to stimulate (make sure to follow warnings above when choosing muscle!)
+- You can use the settings below to test pain relief and muscle contraction
+
+- Settings recommended by manual for pain relief:
+    - Pulse rate: 70-120 Hz
+    - Pulse width: 70-120 μs
+- Settings for muscle contraction (found by trial and error):
+    - Pulse rate: 20-50 Hz
+    - Pulse width: 260 μs
+
+