Technical support
Do-it-yourself installation of radio detectors – buyer’s guide
3BTech – Security, made easy.
This practical guide will help you to install the radio alarm system’s sensors (PIR, PIRCam, opening, glass break, vibration, smoke, water leak), the keypad and the siren yourself, safely and without errors. The examples are written for U-Prox/Ajax type systems, but are also useful for other Grade 2 wireless systems.
Important: for life protection devices (smoke/CO) and high-risk objects, it is recommended to involve a professional. Always follow the manual of the specific device.
1) Preparation – 30 minutes of planning saves many hours
Checklist: - Floor plan/simple sketch: entrances, windows, corridors, valuable zones. - Expected location of the hub: central, hidden, near 230 V + LAN, with good GSM/Wi-Fi reception. - RF environment: thick reinforced concrete, metal surfaces, mirrors, machine housings, inverters → can shield the signal. - Partitions/groups: do you need to manage the living space, garage, outbuilding separately? - Entry/exit route: where do you go in/out most often? (keypad and delayed zone are located here) - Pets: size, movement habits (important when setting up PIR).
Recommended tools: spirit level, pencil, screwdriver/small drill, double-sided industrial adhesive (for temporary positioning), ladder, cleaning cloth.
2) General installation rules (for all sensors)
Height: the optimal height for most PIR/PIRCams is 2.2–2.4 m. Keep this.
Field of view: look “crosswise” in the direction of walking (not perpendicular to the approaching door), this improves detection.
Avoid: direct sunlight, heat sources (radiator, fireplace, indoor air conditioner), moving curtains, reflective glass.
Metal/concrete shielding: there should be an “open path” between the hub/repeater and sensors; do not place a sensor behind a large metal cabinet.
Mounting: first test positioning (double-sided adhesive), then final screwing. Do not drill until the signal level/walk test is good.
Tamper: the tamper switch on the back must close – always close the cover with a screw.
Batteries: only touch the factory battery in the final position (some devices activate the radio when inserted).
3) Hub/Repeater Placement
Hub: Indoor, hidden location (not above the front door), at a point with good reception. Close to 230 V and – if used – LAN.
Repeater: If the signal level is weak due to 2–3 thick ceilings or a large floor area, plan a repeater in the middle.
Test: Walk around the area using the app’s RF/signal level display (or built-in test).
4) Quick installation guide by device type
4.1 PIR motion sensor (indoor)
Height: 2.2–2.4 m; look across the hallway/traffic.
Typical coverage: 10–12 m / 85–90°. The exact value is given in the manual.
Pets: do not look at stairs/top of dresser; adjustable sensitivity; “pet immune” is typical for approx. 20–30 kg.
Walk-test: unarmed walking test – LED flash/signal in the log.
4.2 PIRCam (photo verification)
Like PIR, but do not look at a window/mirror (lighting may be reflected).
Night vision: test in the dark, see if you can see the face/height details.
Privacy: indicate where in the household the picture can be taken (legal and ethical use).
4.3 Opening sensor (door/window)
Placement: near the edge, where the gap is smallest. The magnet is on the moving leaf, the transmitter is on the fixed frame.
Distance: keep the max. gap according to the manufacturer (usually 10–20 mm). Spacer for large play.
Direction: the magnet should be on the marked side (polarity may matter).
4.4 Glass break detector (acoustic)
Visibility range: the microphone should “see” the glass (do not cover it with a curtain), typically 3–7 m range.
Noise environment: avoid continuous loud noise (kitchen appliances, workshop), fine-tuning may be necessary.
4.5 Vibration/shock detector (door/window)
Surface: clean, grease-free; screwing is better than gluing.
Sensitivity: medium/high for doors, medium for windows; test with a stronger knock.
4.6 Smoke detector (optical) / Heat detector
Smoke (optical): on the ceiling, ≥50 cm from the wall; avoid corners, under strong air-conditioned air flow.
Kitchen: a heat detector is preferable there, because steam/oil smoke can cause false alarms.
Bathroom: smoke detectors are not recommended due to high humidity.
4.7 Water leak sensor
Locations: washing machine, sink, washbasin, boiler, floor drain; at the lowest point of the floor.
Test: pour a little water under the sensor – it should signal immediately.
4.8 Indoor/outdoor siren
Indoor: clearly audible, but not easily accessible.
Outdoor: protected from rain, high; tamper connection active; check visibility and mounting.
4.9 Keypad / access
Location: at the main entrance, on the entry delay route; at eye level.
Security: assign codes to each family member; guest code timed.
5) Pairing and setup in the app
Add device via QR code → set name and room (e.g. “Living room PIR”).
Partitions/groups – which sensor belongs to which section.
Delays – entry/exit at the main entrance.
Notifications – push/SMS/telephone; enable PIRCam image transmission.
Test mode – walkthrough, check logs; tamper opening test.
6) Handover to yourself – quick checklist
Each sensor has a name and room.
RF/signal level in the green range.
Walk test passed without false alarms.
Siren is loud, tamper is working.
PIRCam sends a series of images in the log when an alarm occurs.
Codes set (individual, guest), app permissions
7) Typical errors and quick solutions
Weak signal: move hub by 1–2 m; install a repeater; do not have large metal objects in the immediate vicinity.
Many false alarms with PIR: look crosswise; reduce sensitivity; do not look at air conditioner/heater.
PIRCam dark images: adjust to a different angle; check IR/LED illumination; do not have glass reflections.
Door sensor does not close: gap too large → spacer, magnet closer; check the marked side.
Smoke detector is wrong: use a heat detector in the kitchen; clean the grille from dust every 3–6 months.
8) Maintenance
Batteries: app warns → replace within 1–2 weeks, with the same type.
Annual inspection: walk test, tamper test, siren sound test, smoke detector test gas/test button.
Cleaning: PIR/PIRCam lens with a soft cloth; cleaning water sensor contacts.
9) FAQ
Can it be attached with double-sided adhesive?
Yes, for a trial period. Screwing is recommended for permanent installation.
What is the real range?
Depends on the map and walls. If in doubt, plan a repeater.
Does it work with pets?
Yes, with pet-immune PIR and proper placement.
Do you need remote monitoring?
Not mandatory, but recommended. SIA/CID compatible systems can be easily connected.
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Planning and preparation: Determine the areas where you want to install the sensors and detectors. Check the availability of the devices and accessories required for the alarm system. Read the installation guide and familiarize yourself with the devices. Installing sensors and detectors: Install the motion detectors in the desired locations, such as near the front doors or windows. Install door and window sensors that detect when they are opened or closed. Consider installing smoke detectors, gas detectors, and other specialized sensors, if necessary.
Install the alarm center: Place the alarm center in a location that is easily accessible but difficult to see. Connect the alarm center to a suitable power source and network. Set up wireless communication: Pair the sensors and detectors with the alarm center by setting up wireless communication. Check the communication and make sure that the sensors are sending data to the alarm center correctly.
Setup and test: Set the desired sensitivity levels and alarm settings in the alarm center. Test the system to make sure that the sensors and detectors are working properly and activating the alarm when necessary. Important notes and points to note: Read and follow the installation instructions of the devices, as specific devices and systems may vary. Ensure the correct installation height and position for optimal operation of the detectors and sensors. Make sure that the alarm system's communication signal is not interfered with by other electromagnetic devices or obstacles. Learn how to operate and handle the alarm system, and regularly check the condition of the sensors and batteries. If necessary, consult a professional or installation service provider