Cutdown-Circuit

Any code related to the cutdown circuit.

test-cutdown-timer

Assuming the cutdown circuit is set up properly with the GPS Ultimate Shield, this will activate the cutdown circuit after 15 seconds.

Cutdown Circuit 2

Contains code to activate the cutdown circuit. Important notes:

• The current cutdown pin is pin 12. If another device is currently using this pin, this will have to be changed.
• The cutdown activation duration is 8 seconds. Depending on how long the cutdown circuit needs to be activated to fry the nichrome wire, this value can and should be changed.
• This is a basic version of the cutdown code that can't be called with interrupts.

Some more documentation, code explained:

• The cutdown circuit takes about 8 seconds to get sparked, and needs a voltage of 9V. The Particle board doesn't provide that voltage, but it does flick a pin that's connected to a relay switch. -- To alter time, change CUTDOWN_TIME_MILLIS.
• PIN Documentation can be found here.
• The pins need to be set to OUTPUT mode first. This is so they can be set either HIGH or LOW. This is done in setup().
• The Particle board can be hit remotely, through an HTTP POST request. This can be done through either this command - curl https://api.par373037383634/cutcirc2 -d access_token=xxxx(the access_token can be found on the Particle Console), or through the "Function" option on the Particle Console.
• A "function" has been registered with the Particle board, to accept HTTP POST requests on the URL mentioned earlier.
• The function introduces a complication - code that is called through that listener CANNOT be blocking. Originally, the code had a delay(CUTDOWN_TIME_MILLIS), but this was causing the system to crash (sometimes). Therefore, this approach can't be used to hold the PIN to HIGH for the 8 seconds needed for cutdown to happen.
• To get around this, we have a timer to go off. The timer document can be found here. This timer is a software timer, and we have a listener for it.
• We use software timers to set the automatic cutdown as well, for 5 hours or so. To alter how long it takes, change CUTDOWN_MINS_LIMIT, from 300 (300 mins = 5 hours) to a new amount of time, in minutes.