Installation of a dashcam is usually a simple process, with some hassle of routing the power cable under the plastic trim. In most cases, the camera power cord simply plugs into the ACC outlet.
I decided to go with an alternative way of direct connection to the rearview mirror cable. The rearview mirror cable has constant power as well as a switched line, which is perfect for powering a dashcam. In order to make a true Plug-n-Play setup, I made a little harness with a short cable to power the dashcam. BlackVue cameras are powered by 12-24V power source, so no extra power conversion is needed.
This cable is hidden behind the rearview mirror; makes the whole setup super easy and neat.
The next idea is to add a little circuit, to enable parking mode recording. The functioning will be the same as the BlackVue Power Magic Pro box but integrated with my harness. Work in progress…
A few thoughts about the Power Magic Pro. I think it is a bit of an overkill for the Miata. We don’t need 24V range switches. Also, the selection of the two cutoff voltages is a little strange. The 12V (+/- 0.1V) setting would create a deep discharge of the battery, and in cold weather might be impossible to start the car after this. The 12.5V (+/-0.1V) setting will provide a short time for recording. The timer feature seems useless. There are many reviews stating this product is not very reliable. My idea for this device is to use an analog circuit with a cutoff at 12.2V (+/- 20mV), with slight temperature compensation (12.4V at -35C and 12.0V at 60C). I can fit this into an 8mm x 17mm board, which will be perfect for this harness…
Why I chose the BlackVue brand? I was visiting South Korea for business, near Gasan Digital station. My office was on the 7th floor inside a multi-building complex. One day I took the wrong elevator from the underground cafeteria and ended up on the 7th floor, which is occupied by the BlackVue company. So, I decided to check their product and see what I could do with it.
The newest addition is the cable with the USB port (5V/3A), available with battery monitor or without.