Sorry for the crap title, but I couldn't think how to word it? Hi guys, I'm new, and I don't know an awful lot about electronics (in fact very little) so I was wondering if I could pick your brains.
I've got a little project on the go, using a pretty cheap Chinese GPS sat nav tablet, which I want to install into my car (my car has a housing for a 7" screen, but the factory nav doesn't work, and is well out of date anyway. The idea here is to take a more modern touch screen one - http://tinyurl.com/msfsggp - and install it in place of the screen)
Hard wiring in the power adapter is easy - all I'm going to do there is wire a 12v socket directly into the switched live and ground for the existing cigar lighter socket behind the dash. Then I can easily plug the power adapter into it behind the dash, and tie it up out the way. That way I don't have to mess about with stepping down the voltage etc etc, as the power adapter takes care of all that.
My problem is, the unit doesn't have an auto power on and off feature - seems the only way to power on and off is using the press button on the top > press and hold for 2 or 3 seconds and it powers on, press and hold for 2-3 seconds and it goes to a shut down / sleep option screen, and turns off if no choice made in 5 seconds. However, once this screen is inside the housing, there will be no way to access this button! I had to rip apart the casing on this GPS to relocate the PCB inside, in order to be able to plug into the USB cable for power (and later a video cable for rear view camera, but that's further down the line), and this also "releases" the power button from the external button on the casing. It's a simple, two-wire affair - one wire from PCB to a press button, and then second wire back to PCB.
What I'm hoping is someone might know a way to trigger the device to turn on using voltage, rather than a physical press - i.e., vehicle ACC is turned on, and the power from the switched live turns the device on. Powering off isn't really an issue - I'll just cut the battery off so when ACC is switched off, the device will simply "die" (I wouldn't want to leave the battery inside the car anyway, as in summer it will get stupidly hot in the sun, and there's the fear of the battery going pop!)
Some not very good pics;
http://i60.tinypic.com/fmhts9.jpg
http://i59.tinypic.com/jj8e1k.jpg
Now, this device is only my "tester" device. It owes me nothing, so doesn't *really* matter if I kill it - and so far with all the physical messing around with it, making it fit in the housing, taking it out again, etc, the white wire (which is for charging the battery) and both the black wires from the switch have come off the PCB. Yep, it's cheap, and soldered poorly. So if there's a way it could be done so that upon receiving power (to the USB socket, from either in-car adapter or home plug adapter, or even computer USB - I'm thinking all are rigged up to provide 5v to the device) it could power on, that'd be great.
Any ideas?
I've got a little project on the go, using a pretty cheap Chinese GPS sat nav tablet, which I want to install into my car (my car has a housing for a 7" screen, but the factory nav doesn't work, and is well out of date anyway. The idea here is to take a more modern touch screen one - http://tinyurl.com/msfsggp - and install it in place of the screen)
Hard wiring in the power adapter is easy - all I'm going to do there is wire a 12v socket directly into the switched live and ground for the existing cigar lighter socket behind the dash. Then I can easily plug the power adapter into it behind the dash, and tie it up out the way. That way I don't have to mess about with stepping down the voltage etc etc, as the power adapter takes care of all that.
My problem is, the unit doesn't have an auto power on and off feature - seems the only way to power on and off is using the press button on the top > press and hold for 2 or 3 seconds and it powers on, press and hold for 2-3 seconds and it goes to a shut down / sleep option screen, and turns off if no choice made in 5 seconds. However, once this screen is inside the housing, there will be no way to access this button! I had to rip apart the casing on this GPS to relocate the PCB inside, in order to be able to plug into the USB cable for power (and later a video cable for rear view camera, but that's further down the line), and this also "releases" the power button from the external button on the casing. It's a simple, two-wire affair - one wire from PCB to a press button, and then second wire back to PCB.
What I'm hoping is someone might know a way to trigger the device to turn on using voltage, rather than a physical press - i.e., vehicle ACC is turned on, and the power from the switched live turns the device on. Powering off isn't really an issue - I'll just cut the battery off so when ACC is switched off, the device will simply "die" (I wouldn't want to leave the battery inside the car anyway, as in summer it will get stupidly hot in the sun, and there's the fear of the battery going pop!)
Some not very good pics;
http://i60.tinypic.com/fmhts9.jpg
http://i59.tinypic.com/jj8e1k.jpg
Now, this device is only my "tester" device. It owes me nothing, so doesn't *really* matter if I kill it - and so far with all the physical messing around with it, making it fit in the housing, taking it out again, etc, the white wire (which is for charging the battery) and both the black wires from the switch have come off the PCB. Yep, it's cheap, and soldered poorly. So if there's a way it could be done so that upon receiving power (to the USB socket, from either in-car adapter or home plug adapter, or even computer USB - I'm thinking all are rigged up to provide 5v to the device) it could power on, that'd be great.
Any ideas?