How to provide power to Arduino after a remote button is pressed

Question

I have one of these IC 2262/2272 Wireless controller and receiver. If managed to connect it in such way that the Arduino blinks a LED after a button is pressed, it works fine.

My question is, is it possible to power up the Arduino - allow for power go to it, after I've pressed a button ?

The final product I'm aiming to build is a remote controlled car alarm, that will check for pressure changes and text/call me if such are detected, when armed. Ideally I wouldn't want to have the circuit run constantly as when it's checking only once every 10 seconds for pressure change and tehre's no GSM shield connected yet, it went trough a 2000-2600 mAh (Not original and a bit used so not sure the exact number) portable battery in 20 hours, so letting it run isn't great for my car battery.

I'm pretty sure this question is more for this Stack as I'm asking how to essentially power the Arduino on demand, and not anything else Arduino related.

Answer 1

This post is not about removing the power, but put it to sleep and wake it up via an interrupt via a signal. However, in this case, the Arduino should use only a few uA and not drain your battery. Make sure that you also power down the sensor and unused peripherals. To get rid of the last uA's, you can use the relay as is proposed in the comments.

You can set the interrupt with:

attachInterrupt(0, wakeUpNow, LOW); // use interrupt 0 (pin 2) and run function, 

Create a function for the interrupt (wakeUpNow)

void wakeUpNow() // here the interrupt is handled after wakeup
{
   ...

And in the loop let your Arduino sleep

sleepNow(); // sleep function called here

Where sleep is a function like this:

void sleepNow() // here we put the arduino to sleep
{
 set_sleep_mode(SLEEP_MODE_PWR_DOWN); // sleep mode is set here
 sleep_enable(); // enables the sleep bit in the mcucr register
 attachInterrupt(0,wakeUpNow, RISING); // use interrupt 0 (pin 2) and run function
 sleep_mode(); // here the device is actually put to sleep!!
 sleep_disable(); // first thing after waking from sleep:
 detachInterrupt(0); // disables interrupt 0 on pin 2 so the

}

For a complete example, see Waking up an Arduino with input from a sensor

Answer 2

Those remote modules come in two or three flavors. Latching aka press a for on, press it again for off, momentary aka only on when a is pressed, and timed, press a for on 10s.

The first is the easiest, it enables a plain relay or mosfet or transistor for your circuit power. The second would require a latching relay or self latching relay circuit. The third could also use a latching relay.

Regardless, you still want to minimize the arduino power draw due to unneeded circuitry and full on cpu usage. For automotive or battery power, you must use sleep modes to enable low power usage. To be frank, the arduino library is not well suited for this and you'd be better off programming it with direct atmega commands.

Answer 3

A circuit like this would work. Press a button to turn on the Arduino, the Arduino then holds the circuit on until your sketch turns it off.