What is it?

NEW version released! --- NEW version released! --- NEW version released!

There are some things that we need to solve if we want to use a Raspberry Pi in a car, boat, or something similar.

First is a power supply. In a car, we have 12V and we need 5V. Second is to power ON and properly power OFF (to avoid corruption problems with the SD card).

There are some solutions on the internet but I didn't find anything which included all my requirements.

Features

• no additional battery, only use the car battery
• no additional switch, only automatic power ON and power OFF with an ignition key
• integrated DC/DC power supply for the Raspberry (5V)
• same dimensions as a Raspberry Pi for easy mounting

Module functions

• power ON the Raspberry Pi after the ACC/IGNITION is ON for more than 30 seconds (default)
• properly shutdown the Raspberry Pi after the ACC/IGNITION is OFF for more than 15 seconds (default)
• power OFF the Raspberry Pi 45 seconds after shutdown start
• auto cut-off built-in DC/DC step down power supply, so there is no standby current consumption

Technical details

• input voltage: 12V (car battery)*
• output voltage/current: 5V/5A*
• PCB dimensions and mounting holes are same as a Raspberry Pi 3
• PCB is attached upside down (on the bottom side of the Raspberry Pi)
• output power connector is USB type A
• input connector with 3 screw pins (+12V constant, GND, +12V ACC/IGNITION)
• 2 pin headers for interconnection with the Raspberry Pi (+3.3V, GPIO21)
• 2 jumpers for change delay time (after ACC/IGNITION is ON, after ACC/IGNITION is OFF)*
• LED to indicate ACC is ON
• LED to indicate DC/DC power supply is ON

The module is attached to the bottom side of Raspberry Pi, so the top side is free for another purpose.

• DC/DC step down power supply is on the standalone PCB and attached to this PCB. This DC/DC is finished product from eBay/AliExpress.
• For connection power supply to Raspberry Pi use short USB_A to micro_USB cable (male/male) or adequate splitter cable if needed to power some other equipment.
• For connection, +3.3V and GPIO21 pins use jumper wires (2.54mm, female/female).
• Jumper for power ON delay (if exist, time is 45 seconds). On PCB marked T1.
• Jumper for shutdown delay (if exist, time is 30 seconds). On PCB marked T2.

How it works

INSTALLING PYTHON SCRIPT FOR SHUTDOWN:

For use this module you need to create a Python script and allow it to run at boot time. Script and procedure are described in the documentation file.

CONNECTION:

• Connect +12V constant, GND and +12V ACC/IGNITION to the screw terminal.
• Connect 2 pin marked +3.3V and GPIO21 to the Raspberry Pi.
• Connect USB/micro_USB cable from module to the Raspberry Pi.

MOUNTING(optional):

You can use standoff spacer for mounting this module on the Raspberry Pi.

POWER ON

After ACC/IGNITION is ON, the micro-controller is waiting for “power ON delay time”.

If the time does not elapse, the output power is not activated so the Raspberry Pi will not start.

If the time does elapse, the micro-controller activated DC/DC power supply and Raspberry Pi will start to boot. After boot process has started ACC/IGNITION is temporarily disabled because of proper boot procedure (45 seconds).

If ACC is back to OFF position before elapsed “power ON delay time”, the whole process starts at the beginning after ACC/IGNITION is ON again. This allows short temporary ACC/IGNITION ON without starting the Raspberry Pi (if you forget close your windows or something that requires ACC/IGNITION ON, Raspberry Pi will not start before “power ON delay time” elapses).

POWER OFF

After ACC/IGNITION is OFF, the micro-controller is waiting for “shutdown delay time”.

If the time does not elapse output power is still activated so the Raspberry Pi continues running.

If the time elapses, the micro-controller sends a command to activate the script in the Raspberry Pi to properly shutdown and turn OFF DC/DC power supply (45 seconds after the shutdown is started).

If ACC/IGNITION is back to ON position just after the shutdown script starts or in time before DC/DC is powered OFF (30 seconds), Raspberry Pi will restart and boot immediately without delay. This is the fast boot method.

Price is for Raspberry Pi Automatic ON/OFF module only. USB cable, Raspberry Pi, acrylic case and other things on the pictures are not included.

If you want some other time settings, leave me a message.