Gary Littlemore
Posts: 327
Joined: Thu Oct 11, 2012 11:52 am
Location: Cheshire, UK

Carputers

Tue Jul 30, 2013 12:00 pm

For all those who are looking to create a Carputer, This kickstarter is a must. I've backed... http://kck.st/17PuWpb
3b+, 2b, b+, b, Zero & Zero-W

tekmanro
Posts: 14
Joined: Tue Jul 17, 2012 9:57 pm

Re: Carputers

Thu Aug 01, 2013 7:24 am

Is there an open source alternative I could try building on my own?

Just can't bring myself to spend $28 on the power supply when the entire computer cost $25 :roll:

Jerry_k
Posts: 31
Joined: Wed Oct 10, 2012 7:20 pm

Re: Carputers

Tue Aug 06, 2013 11:56 am

it looks like step-down dc-dc controller:
http://www.ebay.com/itm/12V-to-5V-2A-DC ... 27ce66b2d1

with transistor (probably NPN) and some chip (dont know for what is usefull)..

Principe: When ignition switch is on, Gpio = HIGH, When ignit. is turned off, GPIO = low, rpi is shutting down (you can do with python code), while rpi is turning off, capacitor is discharging, and after discharge, rpi is disconnected.. maybe one diode between ignit. and capacitor could be good because capacitor could discharge wrong way, and much faster...


free alternative looks like:
Attachments
Pi Power Supply.jpg
Pi Power Supply.jpg (24.55 KiB) Viewed 1816 times

tekmanro
Posts: 14
Joined: Tue Jul 17, 2012 9:57 pm

Re: Carputers

Wed Aug 07, 2013 11:00 pm

Jerry_k wrote:it looks like step-down dc-dc controller...
I don't think it's that simple. For starters, a capacitor wouldn't be enough to supply sufficient power for the Pi to shutdown (unless it's a boatload of Farads), since the Pi can take several seconds to safely shutdown.

It probably has a microcontroller and a relay, with perhaps an optocoupler off the Ign/Acc line into a micro GPIO. My guess is it also (or should) have 2 power regulators (a very small switching one for the micro and a larger one to power the Pi+accessories). Otherwise if there was a single large regulator you would wake up to a dead car battery after a long weekend.

mraught
Posts: 17
Joined: Sat Aug 18, 2012 3:14 am
Location: York, PA USA

Re: Carputers

Tue Aug 13, 2013 1:06 am

I also backed this kickstarter. I have one of his original style (with rocker) switches and it works perfectly. I joked that it was almost a disappointment because it was so easy to set up, I didn't have to fight it to get it working. :) I love it though. I backed the kickstarter for the car version and I also ordered 2 of the newer style (one with switch, one without) as well.

-mark

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