Install motion detector later

If a motion detector is required, most installations already exist. What should be noted if you want to install a motion detector later, we have summarized in the following guide for you.

Install a detector later on an existing building

Motion detectors are usually desired when the house installation has long since been completed, ie mainly in existing buildings. The subsequent installation of a motion detector is not particularly difficult. However, you should prepare the installation well. There are several aspects to consider:

  • what kind of motion detector
  • Positioning and surveillance area
  • Properties of the existing electrical installation

The type of motion detector

There are three main types of motion detectors:

  • PIR detector (infrared)
  • HF detector (high frequency)
  • Photocell detector

The first two groups are most common, including infrared motion detectors. The PIR detectors react to heat, so they need direct contact with the creature or object that triggers the circuit. In contrast, HF detectors can also be installed hidden behind stems or even walls, so they do not require direct contact.

Positioning and surveillance area

The position of the motion detector is crucial, as well as the electrical installation must be made. At the same time, however, the position must be selected so that the area to be monitored is optimally covered. In existing buildings in particular, it will often be a compromise, so that not too many walls have to be pitched.

Properties of the existing electrical installation

LEDs as consumers

Here, above all, the existing consumer that is to be switched, is of importance. The switching range must match the voltage consumption of the consumer. In particular, the more frequently used LED bulbs require significantly less voltage. In addition, it may be necessary to use a motion detector with a relay circuit, as the circuit in the detector can cause residual current that makes the LED light light up easily.

Installations with timer

If a motion detector is to be installed in a lighting system that works with a timer, the motion detector and timer should be equipped accordingly. This means with the motion detector an impulse function. The timer again requires a corresponding input for such a motion detector.

Tips & Tricks

For the actual installation, various guides are available in the house journal to illustrate the different circuit diagrams. So here you can see how a motion detector is connected, while here we illustrate how two motion detectors are connected in series.

Video Board: Home Security on a Budget Motion Sensors from Harbor Freight