HelpMe! Trigger using EMG

First of all, the MyoWare Muscle Sensor can be connected to an Arduino, and the Arduino connected to a laptop (which is not connected to the mains electrical grid). So, we can see the data acquired from EMG in real-time, using serial monitor (see https://www.arduino.cc/reference/en/language/functions/analog-io/analogread/ )

void setup() {
Serial.begin(9600);
}

void loop() {
Serial.println(analogRead(pin));
}

Schematic is here https://learn.adafruit.com/assets/28668

What's the problem?

Unfortunately, whilst the voltages for fist-clenched and non fist-clenched (relaxed hand) are likely to be significantly different. The voltages for other hand actions (e.g. shaking hands, holding a pen, gripping a mouse) might not be so different to the voltages we get for fist-clenched!! So erm, first of all we need to see what kind of voltages we get from the EMG sensor for different hand positions! 

Additionally, different people will produce different voltages! So we need to try this for for several people too. Well, it will be a fun experiment to get data for that I think! And it might be useful for others to use!

Training the HelpMe!

Now, of course, there is another thing we could do! We could get each HelpMe! to learn the the correct voltages corresponding to fist-clenched for each individual user. Well, to be honest, I think this is the only approach! Since we don't have a one-size fits all for fist-clenched voltages! So I guess we will have to do this with software on the Feather, the smartphone app (to direct the user what to do e.g. clench you fist for training purposes, and to instruct the Feather which code to run). We can save the results to the MicroSD on the Feather.

I guess everyone is thinking, oh isn't there some machine learning thing we can do instead? Yeah, I did think of that. We could collect a large dataset of different hand position voltages. Maybe it is something to think about in the future..

Haptic Feedback

So, the idea is to provide haptic feedback for the user when an alert is triggered, and when the alert has been received by a trusted friend. I found these very small vibrating motor discs which could be used to deliver the feedback (size 10mm diameter, 2.7mm thickness; 11000 RPM at 5V, 0.9 grams). These could just be switched on/off. Or else, we could use a small motor driver - e.g. the  DRV2605 from TI - chip. This has an in-built library of various motor effects! You can see these waveform library effects in the datasheet here https://cdn-shop.adafruit.com/datasheets/DRV2605.pdf . So that would be pretty cool, in order to provide different types of haptic feedback for each situation! Adafruit already put the chip on a board (size 18mm x 17mm x 2mm, 1 gram) schematic here .

Alert cancellation: 

This would occur via the user giving a passcode to the smartphone app.

Example of operating instructions. It is called HelpAI because I called it this when it was an xprize entry. It didn't make the semi-finals :-( Anyway, these give an idea of what it's all about, but are not entirely correct for my updated version. You can see it was going to use the Guardian Circle smartphone app to alert trusted friends.

NTRODUCTION:

The HelpAI system is designed to allow you to trigger an alert message that is sent to your network of emergency responders discretely and quickly in case of physical attack. You can trigger the alert message by making a fist with your left/right hand and holding it for 60 seconds. For the system to function, you will need to wear a special armband just below your elbow at all times. This armband will be continuously monitoring your hand, so if your hand remains in a close fist position for 60 seconds, it will send a message to your smart-phone informing it that you may have triggered an alert message.

WHAT TO DO IN AN EMERGENCY SITUATION

You should hold your hand closed in a fist position for 60 seconds or greater. It doesn't matter if you hold it in this position for longer than that, but you must hold it in the fist position for at least 60 seconds! Once the system has detected this it will ask your smart-phone if it has access to either WiFi or mobile networks in order to notify your emergency responder network. If it determines you do have access to WiFi or mobile networks via your smart-phone it will inform you by vibrating your armband for 10 seconds approximately.  Once you receive this vibration you can be sure that the system has notified your emergency responder network that your require assistance.

WHAT HAPPENS IF I TRIGGER AN ALERT BY MISTAKE?!

In some situations the system may incorrectly think you wish to trigger an alert! Perhaps you are shaking your fist at someone! Or perhaps you are trying to open a jar or bottle! Or gripping something tightly! In these situations, the system will again provide that vibration that it has detected an alert and is ready to notify your emergency responder network. You now need to access your HelpAI smart-phone application and enter your passcode to cancel the alert. You will have 60 seconds to perform this action from the time your confirmation vibration begins.

SETTING UP YOUR HELPAI SYSTEM

1. Download the HelpAI app and the Guardian Circle app from the app store using your smart phone

2. Complete instructions for setting up your network of emergency responders using Guardian Circle

3. Enter the HelpAI app and follow setup instructions to enter your cancellation of alert password and couple using bluetooth with the armband. Remember to leave bluetooth and wifi active on your smart-phone at all times!

4. Try out putting on your armband! You should place it around 3 fingers width from your elbow, on the inside part of your upper forearm. The images in the HelpAI app will guide you through the placement process.

5. Now you are all ready to go! Let's try triggering an alert and then cancelling it! Hold you hand in a fist for 60 seconds and see what happens! You should get a vibration on your armband! Now open your HelpAI app and cancel the alert by entering your cancellation of alert password.

6. Now, for a final check! Let's notify the people in your emergency responders network that you are going to try out the system and see if it works! Give them all a text/whatsapp/DM/etc. that you are just trialling the system and not to worry! For example "I am going to try my new HelpAI system at 9pm so this is just a test but please let me know when you received my alert!"

7. Now, hold your hand in a fist for 60 seconds. You'll get that vibration on your armband. Don't do anything!  Give it a couple of minutes and check your notifications! Hopefully they will all be saying "we got your alert".

8. So you are done! Just remember when you might send out false alerts! Shaking fists at colleagues for instance!? Or when you are struggling to open a jar or bottle!

CHARGING MY HELPAI SYSTEM

The HelpAI system will let your know when the battery for your armband is low via notifications on your smart-phone using the HelpAI app. You can charge your armband using your laptop or other USB hub. You'll need a USB to micro-USB cable to charge it.