Fridge door alarm - REMAP - Custom made equipment for disabled people
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Fridge door alarm

Client suffers from severe short-term memory loss following a motorcycle accident. Fridge and freezer doors are left open and an alarm system to respond to doors left open was requested.

Two identical door sensors and timer alarm systems were supplied. The door sensors were heavy-duty surface contacts type TZ45Y in which the normally open reed switches were changed for the normally closed contacts of type N95BT form C reed switches. The operating range of these sensors is 40mm. The timer units were based on universal timer modules type I-1 (Quasar Electronics), which can be set to give a delay of 1-180sec. in a time out from power-up mode. Packs of 10 rechargeable AA cells were used for providing the 12V supply and a battery charger was provided. Very loud sounders type N15CL were utalised to alarm if a door was left open for longer than 60sec., a battery test button was supplied which sounded the alarm when pressed if the batteries were OK. The sounders gave a very brief beep when a door was opened, this gave confidence that it was working. All part numbers above with the exception of the timer modules, are Maplin components. Circuit diagram, photograph, parts lists and operating instructions are included as separate sheets.

The client can be certain not to leave the fridge or freezer open.


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