Saturday, February 6, 2016

Turning a Dash Cam into a Surveillance Camera

I've had to come up with a solution to a strange problem.  A relative thinks that someone is stealing their pot plants at night.  To see what's really going on a surveillance camera would be great.  The main problem is that most of the options on the market are just cameras that send an image back to central location for monitoring or recording.  This can be via a wireless connection or physical cables.  I don't want that, I want something really simple.  There's no internet connection or wireless network at this place, so that rules out a lot of options.  I can already hear people saying things like, Raspberry Pi, zone minder, WiFi dongle, IP camera, webcam.  Totally agree, if I was living there and had time to tinker, that's probably what I'd do, but this isn't one of those projects I'm doing because I love it, it just needs to get done.  Besides, I can see what would happen.  Project goal is to install a surveillance camera, spend a week in Linux trying to figure out why the webcam drivers don't work, or tracking down that the Raspberry Pi is restarting because the power cable isn't thick enough for the current it needs.  Screw that.

There is a far easier solution though, and luckily I had all the parts.  Take a car dash cam and power it from mains electricity though a timer.  Boom, done.  Well, not quite.

dash cam
Dash cam running on mains power
My father happened to have a spare dash cam he bought cheaply at ALDI.  It's not state of the art, but image quality is good, and it has some nifty features that will come in handy.  The display isn't of much use, but for aligning the camera it will be useful.

The plan is to have the timer come on at 6 pm and go off at 6 am.  This will active the camera in exactly the same way as turning on a car ignition.  Recordings that long will take up a lot of disk space, but luckily this model has a option to only record when movement is detected.  So most of the night the camera won't be recording anything.  If in the morning the relative suspects something has happened during the night, all they need to do is turn off the power to the camera.  I'll then inspect the footage when I'm available.

dash cam
Flip down display
The camera has 6 IR LEDs on the front that come on when it gets dark.  They seem to be rather good LEDs that don't bleed into the visible spectrum.  I can't imagine that they'll do much to illuminate a yard, but, we'll soon find out.

dash cam
The original plan was to use a USB wall wart  from a phone to power everything, but as it turns out, the USB port is for charging and transferring data to a computer.  When a cable is plugged in the camera won't turn on.

dash cam
USB Port
To solve this I used a variable switch-mode power supply I had.  After testing the polarity and voltage of the power supply the camera came with, I replicated that with variable supply.  When connected to the camera with the appropriate plug everything worked fine.  Turn on mains power, and the camera enters standby mode read to capture any motion.

dash cam
Power Port
The timer doesn't really warrant a mention.  It's a simple mechanical timer that if needed my relatives are capable of setting.

The camera is now installed and waiting.  Let's see if we can catch this horticultural hijacker, blossom bandit, perennial prowler, seedlings stealer, leaf larcenist.  Sorry, couldn't help myself. :-)

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