Running Lights. Perhaps the simplest solution, and one that many RV manfacturers (those that are wiring in cameras) are going to. You must turn the tow vehicle's lights on for the camera to turn on as the tail/clearance lights must be on to power the camera. Since the camera is typically located high and centered on the rear of the RV, often the center clearance light is mere inches from the camera, making the wiring easy.

The only disadvantage is if the RV used insufficient gauge wiring and adding another load dims the lights. This can often be minimized by upgrading to LED clearance and tail lights. However, I am not using this solution as I would otherwise have a unused switch plate/hole in the cabinet.

I designed, built, and tested prototypes for the next three solutions and they all worked. I will provide information later on this webpage should you desire to build one.

Brake Lights. With this version, a tap to the brake lights is monitored, and everytime it senses the brake lights are on, the camera will be turned on. The camera will continue to be powerd for 1, 2, or 4, hours, depending on a switch setting in the module. Each time a subsequent brake light event is detected, the timer is reset, thus the camera will be powered for 1, 2, or 4 hours after the last brake light event.

This will work on RVs having brake and turn signals on the same light, and works with incandescent and LED bulbs. The chief disadvantage is accessing the wiring of the brake lights to the camera.

Wireless Relay. This solution takes advantage of the popular and low-cost wireless relays that can be had on eBay, Amazon, and many other places. Simply, the camera is connected to the relay contacts, and the remote transmitter can turn the camera on or off.

The chief disadvantage is having to remember where the transmitter is, and replacing it's batteries on occasion.

Magnetic Compass. This version is strikingly similar to the Brake Light version with the exception that the module contains a magnetometer. When it senses a change of direction, the camera is powered. And similar to the Brake Light version, a 1 hour timer is reset each time a change of direction is detected.

The primary disadvantage is the camera does not come on until you make a 45deg change in direction, which means you will not initially have the camera available until the RV turns. In the rare occasion you must back out of a spot, the camera will not be available.

For both Brake Light and Magnetic Compass version, you can also build one as a theft alarm by connecting the output to an alarm horn, klaxon, or other noise maker. Imagine the surprise of a would-be thief when attempting to steal your rv that the alarm goes off.

In each section below, you will find links for the instructions (including bill-of-materials, schematic, and parts layout), circuit board, and in the case of the brake and magnetic switches, the Arduino Sketch.

Version	Instructions	Circuit Board	Arduino Sketch	Arduino Libraries
Brake Switch				none required.
Magnetometer		<		TinyWireM.
Wireless Relay Switch

If you have never built an ATTiny85 based project before, you will need to setup a computer to load the microcontroller with a sketch (firmware). I have done quite a few RV projects on this website, and the link below will show you how to get started with the ATTiny85.

If you are building the magnetometer switch version, you will also need an Arduino library for the ATTiny85 as shown above. I used version 1.0, but version 1.1 should also work (version 1.1 was not available when I did the programming for the magnetometer switch).

If you would like to construct the switch plate as shown in the video, here is the exploded view of the construction. All of the components sources and part numbers are shown in the instruction file, except for the front panel itself, which can be found at the Templates page.