Reed Switch Whitepaper

Introduction

The reed switch is an electrical switch operated by applying a magnetic field. Without the magnetic field, the switch is open, with the 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 opened 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)	❌	❌

API 6 downlink register related to the reed switch

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!