Alectro Systems Inc.


The Alectro Systems Door Alarm is a Unique Device


In 1995, Alectro Systems came up with a unique concept for a Fridge/Freezer Door Alarm. Although the basic concept has remained, it has gone through many generations of upgrades to arrive at the current DA20 model.

There are some basic "Door Open" door alarms and some Temperature Sensing alarms available, but these didn't accomplish what we wanted.

"Door Open" alarms are annoying because they sound all the time the door is open, and Temperature alarms are not much help, because they respond too late.

The Alectro Systems Door Alarm remains silent while the door should be open, then alerts you when it has been left open too long.

Price and Data Sheet

Typical Applications

Due to it's unique features and reliability, the Alectro Systems Door Alarm has found it's way into many diverse applications. The obvious one is Fridges and Freezers which contain food. Leaving these doors open too long can have costly consequences.

These devices are also extensively used in Medical, Institutional and Industrial applications. One of the US States purchased 500 of these alarms for their immunization program.

Below are some of our typical customers and applications:

Doctors, Dentists, Clinics, Hospitals, Pharmacies, Labs

To protect refrigerated medications and samples.

Restaurants, Institutions, Homes

To protect refrigerated and frozen foods.

Institutions and Industry

To prevent exit doors from being propped open, and cupboards from being left open.

Some Key Features

Works with Any Door

Although it was initially designed for Freezers and refrigerators, the unit will easily mount on any door, wood, plastic or metal. We have customers who use the device on entrance doors to prevent them from being propped open.

Silent while the door should be open

The delay features ensures that the alarm remains silent while you are accessing supplies. This eliminates the annoyance of a constant alarm sound when it is not required.

Warns when the door has been left open

If you forget to close the door, or don't close it properly, the alarm will sound to let you know. This too is accomplished by the delay feature which determines that the door has been open too long.

Easy to install without tools

Installation is very easy and effective. Both the main unit and magnet are fastened using double sided tape. This tape is already attached to the device. You simply remove the protective film and press the alarm onto your surface. The adhesive is very strong, ensuring that it will stay attached.

User Adjustable Delay

The Standard unit has a delay, pre-set to about 5 seconds. This can be easily adjusted between 0 seconds and 21 minutes. Instructions are provided.

Loud enough for most applications

The Standard units are loud enough to be heard throughout an average 3 story house or small office. The sound pressure level is 85 db at 10cm. An industrial version is also available with a loud siren.

Long Battery life

The DA20 is now has the ability to generate a low battery warning. Due to the very low current drain, when the door is open, and no current drain when closed, the unit typically provides more than a year of service under average operating conditions. It is supplied with a 9 volt alkaline battery.

Designed and Manufactured in Canada

The Alectro Systems Door Alarms are high quality devices, designed and manufactured in Canada. They come with a 1 year warranty.

DA20 Standard Alectro Systems Door Alarm


The DA20 is very easy to install on any freezer or fridge without any tools. It will work on any appliance, upright or chest. In fact it will work on any door in your building. The DA20 has an adjustable delay circuit which allows you to keep the door open for up to 21 minutes without it responding. After this delay, it emits a loud pulsing tone to alert you to the fact that the door has been left open. Once the door is closed, it resets to its monitoring state.

Because of the delay feature, you are not forced to listen to an annoying sound while you want the door open. It will let you know when it has been left open however. Using a set of dipswitches, the user can select the delay time, they can turn the initial chirp on or off, they can turn the LED on or off, they can choose between the pulsing beep or a steady tone, and can even turn the buzzer off (using the LED as a signal that the door is open if desired). All are user adjustable with the included mini screwdriver.

With its very low current drain, the DA20 will probably operate for over a year, under normal use, on one 9 volt alkaline battery (included).

The main unit is 4.4" long, 2.6" High and 1.2" Deep (including mounting tape). With it's sound pressure level of 85db at 10cm, it can be heard throughout a typical 3 story home or small office building.

Click Here to listen to the sound it makes. NOTE: The volume you hear is based on your computer audio setting.

DA10 Door Alarm VideoWatch a 6 minute video about older version of the Door Alarm

Price and Data Sheet

Get the Installation Instructions for the DA20

DA20 Siren Add-On Option

DA-9APD-ASDo you need a VERY LOUD door alarm? Although the standard version is perfect for most applications, some industrial areas require a very loud alarm.

The DA20 Siren is an add on option. This provides you with a system which produces a very loud alarm sound (115 db at 1 Metre).

The siren comes with a 1 foot cable which gets attached to screw terminals inside the main unit. Because there are no connectors, this improves reliability and eliminates the possibility or accidental disconnection.

The main unit and magnet can be attached using double sided tape (supplied) or fastened through screw holes. The siren is attached using screws.

Price and Data Sheet