Introduction: Edison IOT Ignition Interrupt Device

Recently, I was lucky enough to receive one of these awesome Intel IOT Edison developer kits from the sweepstakes sponsored by Instructables and Intel. I am new to microcontrollers. Though I am an auto technician with A.S.E.s and specializing in diagnostics and electrical work in 12VDC and I have some experience from years back in java class, I don't really remember much of it and basically had to start a new. I followed some basic start up procedures to set up the board. I decided to make a safety button for my car;s ignition. Basically meant to be a secret button that would have to be held in order for the key to operate the starter. In the future, I plan to add a numerical key pad for the user to enter in a code, which will then enable the button to start the car for a short period of time.

So to get started you will need an arduino compatable card like the Intel Edison I used, A break out shield to easily connect the wire leads, A touch sensor, though the one I used came in the Seeed Starte kit 2.0 that came with the Intel board. This sensor is a capacitive touch sensor, you can make your own, and there are great tutorials on here about it, I chose to use this one because it comes with a capacitor and resistors built in, so i didn't have to go buy anymore electronic components. You will also need a relay module, I again, used the one that came with the seeed start kit. It should work for what I need since it is rated up to 10A at 30V DC, and all I used it for was completing the circuit that drives that starting system, low power switching low power switching high power. If you don't fully get it now, you will in the coming steps. You will also need some way to power the board, I don't mind the usb power source, but for testing i used the 9V adapter that came in the developers kit. it plugs into the barrel jack and can easily power the board and relay, though for how long I do not know. My final install will use a cig lighter to usb adapter since i have an extra cig lighter socket and they are easy to mount, wire and very cheap to buy, the usb adapters can be bought for about 3 bucks so being able to plug in and out to remove and change is a plus to me. I have not hard wired the adapter in yet because I plan on removing the unit to add the key pad, at which point the key will only operate on or off(my car has no accessory) and the touch sensor will do the starting after the safety code check has been passed!

Step 1: Building

Putting together the unit takes minutes, coding was the most difficult as i didnt really know where to start. This is when i turned to my good friend instructables. I found an ible titled


by gckulo, i copied his code and set up and was happy to have a touch sensor that cycled the relay. But there was a problem, his build was for a different purpose than I had intended. His code allowed the button press to cycle on, then another press cycles off. i needed the action to be momentary. So i set off again to find some code I could borrow and manipulate for my need. The instructions of the Seeed Grove kit suggested that I source code from their Seeed github page, so I did. Since their cap touch sensor can be used like a regular button I copied and changed some code for their relay unit. After Loading this and plugging everything together you will be ready to add this to your vehicle.


const int buttonPin = 2; // the button is attached to digital pin 2
const int relayPin = 7; // the relay is attached to digital pin 7 int buttonState = LOW;

void setup()

{ pinMode(relayPin, OUTPUT);

pinMode(buttonPin, INPUT); }

void loop() { // read the state of the button: buttonState = digitalRead(buttonPin); if (buttonState == HIGH) digitalWrite(relayPin, HIGH); else digitalWrite(relayPin, LOW); delay(10); }

Step 2: Install

As I will be continuing on this idea of an interlock device by adding the keypad, I do not want to fully install mine yet. But I plan on installing it permanently inside of the dash behind the knee bolster. It should be mounted securely and free from touching and metal parts against the board. The best option would be to make one of the cases all over instrucables for these! Then Basically there are two points of wiring to be done. The first would be the power source from the car to the edison board. I will provide mine via the usb port, using a usb car adapter that is inserted into a cig lighter socket wired behind the dash. Ground could be provided from almost anywhere on the chassis inside the car, and power should come from a reliable ignition source, you dont want the edison powered when the car is off, You will end up with a dead battery in the morning. So, now we have power and ground going to the socket, powering the adapter, the usb that comes with the Edison can plug into the adapter and power the edison(only when the ignition is "on." Keep in mind not all ignition power sources stay on when the starter is cycled, many, such as the radio, lose power when the vehicle is operating the starter. So do not supply your cig socket with this ignition power.) The only thing left to wire now is the ignition start wire. For this project we cut the wire coming out of the ignition switch when it is in "Start." This drives the starter relay that operates the starter system. So cut it, one end into one relay terminal, the other in the other relay terminal. The relay interrupts the signal from the key start, and doesnt let it pass to the starting system unless the touch pad is being pressed, while the edison is powered and ready to go.

Step 3: Completing

So that's basically it, It isnt very complicated of a build, code or install. The most issue and time will be figuring out which wires are which on your vehicle. Easiest way to do that would be to get a chilton or haines type manual. You need a non interrupted power source from the ignition "run/on" circuit and to sever the wire coming from the ignition "start" circuit. mount it somewhere it wont get damaged and hide your touch sensor. Because of the sensor's ability to read through materials, you could hide it inside a seat, behind a blacked out panel, really most anywhere. Discretely hold your hand against the sensor while turning the key and no one would even know you had the device. But they will be wondering whats going on when they can't start your car... I will be expanding on this as I mentioned before. I found a great instructable about integrating a keypad for a lock, and plan on using the keypad pass check to gain access to the touch sensor. This will serve two purposes. One, I can use the touch sensor solely for the starting of the car, no more turning the key passed run into start(the key pad adds a requirement to the press of the button. eliminating the possibility of accidentally cycling the starter, if only the button was required to operate it and not the key pad first or the key with the button) and Two, enabling another level of protection to the system. The key code being required, then knowing where the hidden touch sensor is to start. Thanks for the read!

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