Arduino BT CarPC power controller

d_mc_a · 12-05-2008, 07:18 AM

Hi,

I've been getting annoyed at my pc as it drains my car battery alot. I know there are plenty of alternatives but I just wanted to see if anyone has tried this or thinks its a crazy idea. I have an arduinos BT. The great thing about this device is that it can operate on a voltage as low as 1.2v. My idea is to install this in my car with the operating voltage at its lowest so that the range of the arduinos is reduced. I have a small program in the works for the arduinos(not tested yet) that will continually scan for bluetooth devices and trigger depending on the detection of my phone. The idea will be that this arduinos is always powered with a reduced bluetooth range around the car. When it detects the phone in range, It switches on the carpc on, when the phone leaves range, a timer begins that first, locks the carpc for up to 1 minute of no phone detection. If the phone remains out of range for a longer period (probably 5 minutes), the arduino will shutdown the carpc. When the phone comes into range again, It will switch on the carpc. I have been trying to work it our logically so that when I'm near the car, or walk past the car, it won't switch on and stay on.

I'm aware that their might be some security issues with my way of ding this but as the arduino only controls the PC and not the actual ignition, I don't really care about that.

Sorry about the long msg.

Kevin94bird · 12-05-2008, 07:02 PM

Will a startup/shutdown controller not work for you? you can set it to wait an amount of time once the car is off before it shuts down if ignition is not detected again.

84RegalRider · 12-06-2008, 09:19 PM

well since he is using an arduino, i think adding the delay is like two lines of code. haaha

d_mc_a · 12-08-2008, 08:22 AM

Yea, A simpler controller would work but I want to add the possibility of other bluetooth features later on. Triggering other events on the car from the phone, for example changing to a socket connection via bluetooth to the arduinos and some kind of interface on the iphone that can open the boot, or switch on lights without the pc having to be switched on. I have already bought a damaged logitech G15 keyboard off a friend and I'm going to remove the LCD from it and replace the stock clock LCD on my renault with it. I'm not sure how easy it is to integrate a G15 lcd with an arduinos, but I'd imagine someone has tried it. That should allow for some interesting features.

rodweb · 03-18-2009, 10:20 PM

I've been playing around with an Arduino as well this last week or so. They are very clever. To turn the Car PC on, all you need is to trigger a relay in the accessory line that turns on your PC power supply and maybe a sensor on the ignition line so if the engine is on, you don't kill the Car PC as there is no load on the battery.

Another alternative is to sense the battery voltage with one of the analog pins thorugh a voltage divider and if it falls below say 13 volts (eg. Alternator is not charging) allow the Arduino to shut down if the BT signal is lost.

To sense 12 volt voltage, feed the 12v input to a relay (maybe a solid state one) on the input side and switch 5 volts on the Arduino onto the input pin you are using.

I've started to put some stuff together from my car PC

These ar Solid state relays, 2 amps 3-50 volt DC. There are 4 input relays and 4 output relays on this board I will be using. There are two kinds of relays here. One lot handles a 12 volt input (which will be inputs to the Arduino), the other handles 5 volt input (which will be outputs to the Arduino)

I've also got some smaller ones that can switch at < 3 volts.

The LED's represent the buttons on my monitor and when reversing lights are sensed, the Arduino will press buttons to switch inputs. The press button switch represents the reversing light switch. I have put stuff about this on my worklog and the first cut code for the monitor is there.

I will also make the Arduino work as a temperature sensor for RR. I have tested this and it works!

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