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Reed Switch in Simple Hardware Devices


The reed switch is an electrical switch operated by applying magnetic field. Without magnetic field, the switch is open, with magnetic field, the switch closes. This sensor allows Simple Hardware devices to cover a great number of use cases - when combined with a magnet.


The reed switch replaces the button functionality in the SimpleIndustry and SimpleMeter devices and is used to trigger downlink!

There are three API 6 user modes that work with the sensor:

  • Reed switch on/off
  • Reed switch counter
  • Reed switch pipeline

Each of these modes covers a different business logic by having sending different data based on different triggers. Let's have a closer look.


IMPORTANT: The reed switch functionality below works exactly the same with switch/dry contacts!

Reed switch on/off

How it works: When the reed switch closes, a message is sent immediately. When the magnetic field is no longer present and the switch opens, a different instant message is sent. Very simple!


Reed switch on/off is also available in three different WiFi versions. You can read about them right here!

Reed switch counter

How it works: The device will count the number of times the reed switch has closed (number of magnetic field presences/magnet rotations). You can choose the trigger of the message: either it's time (number of switches in e.g. one hour) or the exact count (message sent after e.g. 50 switches.)

Reed switch pipeline

How it works: The device will measure how long the reed switch was open and then how long it was closed. This will then be reported in a message that contains a total of 8 time periods: 4 for both states. E.g. reed switch closed for 12 minutes, then open for 10 minutes, then closed again for 8 minutes, etc.

Reed switch modes comparison table

Mode Reed switch on/off Reed switch counter Reed switch pipeline
Mode hex (API 6) 0x0C 0x13 0x08
WiFi versions available ✔️
Message trigger switch open/closed time/count reached time - pipeline full
Message availability instant customizable as per settings when pipeline is full
Appended payload possible ✔️ (not in WiFi versions)

Reed switch-based modes can be fine-tuned with these downlink registers:

Register name Register hex Register value range What it is and what it does Useful for
Sleep time 0x04 SimpleTime Time after record/message during which the device will ignore any sensor input. Reed switch on/off, Reed switch counter
Reed switch measurement period interval 0x37 SimpleTime How often the processor wakes the sensor up and asks for data input - how often the sensor measures. All reed switch modes
Reed switch pipeline time threshold for exponent selection 0x46 SimpleTime Please see the mode documentation for detailed information. Reed switch pipeline
Reed switch detection delay 0x4B SimpleTime How long should the change of state last before the message is triggered or data recorded. All reed switch modes
Reed switch counter count trigger 0x50 Number 1-255 After how many reed switches should the message be sent. Reed switch counter
Reed switch counter time trigger 0x51 SimpleTime After how long should the message be sent. Reed switch counter

HERE's the API 6 table for more information!