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Questions tagged [reed-switch]

An electromechanical switch controlled by a magnetic field applied to it. The metal contacts are flexible and somewhat resemble parts of reed plants, hence the name. A magnetic field causes the contacts to flex to either make contact with each other or produce a small air gap between them. Use for questions about reed switches, and in conjunction with the "switches" tag. Also consider using in conjunction with the "relay" tag, if applicable.

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Converting reed switch from NO to NC

Does anyone know how to use a normally-open reed switch in a way that is "normally-closed"? I have a device that needs a reed switch attached to its power source. This is because when it is ...
Vagabond4761's user avatar
10 votes
14 answers
3k views

Single-use switch

What are the options for single-use switches to turn the device on? Intro: I am working on a project where I want to have a completely encapsulated device (no ports or opening), but it should have a ...
Bob Becher's user avatar
1 vote
4 answers
152 views

Dual edge detector with binary counter doesn't count correctly

I want to build a circuit that counts the on and off of a reed switch in a CD4040 binary counter. I wired the circuit below in a breadboard. This has a debounced switch connected to a 74HC86 that when ...
CBal's user avatar
  • 13
0 votes
1 answer
109 views

Reed Switch alternative IC, AMR or TMR

I have a prototype that I have built which has 4 positional reed switches arranged in a square around a circle. There is a rotating magnet as shown below: I would like to replace them with solid ...
Jaspal Singh Rathour's user avatar
1 vote
1 answer
46 views

Protection for unpowered ADC module

I'm trying to measure a low frequency (0.1 - 100 Hz) signal with an ADC module. After powering the sensor up the signal can have common mode voltage from -15 V to +15 V and is tuned manually (the ...
Tolik4's user avatar
  • 151
0 votes
0 answers
62 views

Making an automated chessboard [duplicate]

I want to create an automated chessboard. At the moment, I'm making the project and deciding what technology to use to detect which piece is at what position and how to move them. I'm not so skilled ...
Mukund's user avatar
  • 43
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0 answers
197 views

ESP32 based door/window sensor using a reed switch (logic issue)

I have an ESP32-based reed sensor used to monitor door and window events. ESP32 is put into deep sleep mode, and the reed switch is connected to a RTC pin in order to wake up the MCU (external event ...
Suresh Kumar's user avatar
0 votes
0 answers
104 views

On/Off switch for a sealed underwater container

I know this can be done, I just can't put my finger on exactly how to wire it up. I have an underwater housing that I seal up indoors and take out on a boat. The device inside needs to be turned on ...
Bolli's user avatar
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0 answers
71 views

Reed Switch Selection - Quality Control

I have a piece of hardware which uses reed switches and neodymium magnets. When I attempt to produce this hardware in batches I find that some reed switches that I have are more sensitive than others ...
Jaspal Singh Rathour's user avatar
1 vote
1 answer
65 views

Reading the markings on a reed switch

I have the following reed switch. The markings are: 170-842 N/O3 I'm not entirely sure what they may mean. It is used in a DC application to power a 24V, 6A DC motor, but that is all I know about it ...
HFOrangefish's user avatar
4 votes
5 answers
1k views

Placing a reed switch behind a metal plate

If put a reed switch behind a metal plate in plastic casing and have the bar magnet sweep across the plate in parallel, would the reed switch activate? I would try it myself but the reed switches that ...
Zuzlx's user avatar
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1 vote
0 answers
396 views

How can I set up a reed switch/magnets on an electronic chess board to consistently detect pieces?

My goal is to build a chess board that can detect the movement of pieces on it. My current approach that I'm testing is to have a reed switch underneath each square and magnets attached to the bottom ...
James's user avatar
  • 111
0 votes
2 answers
83 views

Turn on load BJT, MOSFET or Relay

I want to turn on a load of around 1.5A with a reed switch. I tried to just use a reed switch but found out pretty quickly that it will not take the current. I was considering a BJT but there is a ...
maxum's user avatar
  • 121
0 votes
0 answers
65 views

Multiple LEDs with reed switches for testing magnet placement

I'm adding MIDI to an old electric organ (saving the existing internals for dual operation). I will be using reed switches and magnets at every key for action. For testing magnet+reed positions I ...
Mandibela's user avatar
0 votes
1 answer
294 views

Detecting magnets regardless of polarity

I'd like to build large matrix of sensors to detect objects placed on it. I can place magnet or metal inside detected pieces. I tried to use reed switch and hall sensors. Hall sensors seems like ...
imperf's user avatar
  • 15
0 votes
2 answers
244 views

Count number of rotation of a rotating disc

I have got a large wooden disc for some purpose which rotates in its center axis. But I need to find the number of rotations or simply stop the disc when number of turns reaches a certain point. So I ...
Sandeep Thomas's user avatar
2 votes
1 answer
2k views

Reed Switches - Good brand, stuck in the closed position problem

I'm doing a project with an Arduino pro mini 3.3v that uses internal pull-up to detect changes on a reed switch sensor. I'm buying the reed sensors from AliExpress, and most of the time they work OK ...
ernewston's user avatar
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0 answers
126 views

Using a reed switch with safety in failure

I'm planning on building something similar to this project to be used as an alarm for when a stair gate is forgotten open. Image above taken from this link: https://www.electronicshub.org/arduino-...
the_new_mr's user avatar
1 vote
2 answers
130 views

Add second sensing circuit to already wired reed switch

In my house I have a mechanical water meter with a 2 wire reed switch that sends a pulse every 10 liters to (I suppose) an electronic meter to witch I don't have access. I'd like to connect a circuit ...
nicari's user avatar
  • 11
0 votes
1 answer
64 views

understanding the datasheet of a normally closed / changeover reed switch, for powering Arduino project

I am working on an Arduino project that should be sealed, with the possibility to switch off when the user wants. A solution I have seen on commercial products is the use of a Reed switch, normally ...
Zorglub29's user avatar
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1 vote
1 answer
394 views

Input matrix with reed switches

I'm about to buy components for my first Arduino project: Reed contacts for my model railroad (H0 scale) to detect track usage. I don't want to use special shields, but use as few components as ...
iGEL's user avatar
  • 111
0 votes
1 answer
116 views

Logic gate circuit to close when sensor signal turns ON and then OFF, but must ignore another ON?

I am trying to put a permanent magnet in a transformer between both coils, so that the transformer can utilize the flux from the permanent magnet by guiding its flux periodically. We have one primary ...
Yogie's user avatar
  • 129
3 votes
2 answers
300 views

Reed switch only triggers with scope probe connected

I've run into a very odd problem. I've created the attached circuit, designed to cut power supply when a magnet is brought near the device. It works perfectly with the reed switch disconnected from ...
Alex's user avatar
  • 101
1 vote
1 answer
111 views

Share a magnetic door contact with a pool alarm and home alarm

I purchased this pool door alarm (289-4,) along with a reentry button (084-3). My house came pre-wired with magnetic door and window contacts (normally closed I believe.) I do not have a home alarm ...
Talsma's user avatar
  • 15
0 votes
3 answers
583 views

Protecting reed switches operating 240V AC relay from welding shut

I'd be grateful for some advice about protecting the reed switches in this pump-down setup I am installing. I naïvely thought that the relay alone, which is rated as drawing only 5.3mA, would be ...
Andrew's user avatar
  • 3
1 vote
3 answers
382 views

Reed switch sensitivity/Strong magnets for 6 ft detection

Can I detect magnetic field from 6 feet distance using Reed switch ? Do I require very strong magnet for it ? I can have low AT Reed switch for more sensitivity but detecting distance of 6 feet should ...
Riddhi Akbari's user avatar
0 votes
1 answer
49 views

Piggyback input power from supply power on SSR?

I would like to use a reed switch to control a solid state relay. Could I use the supply power for the control as well? https://i.sstatic.net/mUnkh.jpg
JoshC's user avatar
  • 1
0 votes
1 answer
163 views

2 Pin Reed Switch Normally Closed Effect using BC547

I am very new to electronics. I am using a reed switch with 2 pin. Which acts as a switch near to magnet. I want to keep the switch ON when magnet is not near and OFF when its near to magnet. I ...
user3201500's user avatar
0 votes
0 answers
276 views

Reed switch passive interupt for garage heater when door is open (using NC switch)?

I'm trying to prevent my garage heater from running while the garage door is open to prevent it from attempting to heat the entire neighborhood if/when the door is accidentally left open. I have a ...
NumericOverflow's user avatar
0 votes
2 answers
85 views

How to use reed switch to change operating modes?

I have a circuit of LEDs - say L1-L10. My requirements: No visible switch Illuminate the LEDs successively (only ever one at a time) every time the user passes a magnetic "wand" over the switch. (...
JJC's user avatar
  • 89
0 votes
1 answer
2k views

What does this circuit do? Reed switch debounce?

I'm trying to reverse engineer a pcb and I'm stuck on this circuit. I believe the capacitors maybe for debounce. The switch is a reed switch. Can anyone shed any light on it?
Samuel Taylor's user avatar
0 votes
1 answer
4k views

Modify Ring Contact Sensor in a series of wired security reed switches

After reading the instructables post on the simplisafe sensor I modified the ring sensor and tried to integrate it with my wired sensors. This is what I found: testing with a spooled wire about 20 ...
lcpr's user avatar
  • 1
0 votes
0 answers
90 views

Using a PNP to enable a NPN current source not yielding expected current

Hi I am trying to switch on a brake light with a reed switch. The load is a 12v (0.1A) LED bike light. The following circuit works in the sense that the light comes on when the magnet moves away from ...
user1247060's user avatar
1 vote
2 answers
696 views

Reed Switch Failure Modes

I've been playing with these through hole reed switches: MDSR-4-12-23. It has been my experience so far that you have to be very careful in handling them, including when bending the leads to 90 degree ...
vicatcu's user avatar
  • 22.8k
3 votes
2 answers
437 views

Timer activated by reed switch on AC solenoid

I am trying to create a 2-digit timer that resets and then starts at the activation of an external AC solenoid, and pauses at the solenoid's deactivation. The circuit I have created (see schematic ...
MartinE's user avatar
  • 31
0 votes
1 answer
77 views

Higher Voltage = Improved Signal Strength

I'm using a reed switch to detect the state of my garage door. It's connected to an ESP8266 via twisted cables of 1.5m and each line has a pull-up as the signal floats too much otherwise. Well it ...
AlessandroEmm's user avatar
1 vote
2 answers
619 views

ESP8266 (esp-07) powered by battery(s) for at least 1 year

Hey all I am trying to see how long I can possibly have a ESP8266 ESP-07 operate with only 1 or 2 of the Lithium-ion Battery 18650 Cell which claims to have 2600mAh. I am making a window alarm sensor ...
StealthRT's user avatar
  • 797
1 vote
1 answer
289 views

Trouble replacing a reed switch with a wired sensor along long stretches of wire

I have a wireless security door sensor, which has a reed switch, and I'm trying to replace the reed switch with my existing wired security door sensors (thus not having to mount the wireless door ...
Dolan Antenucci's user avatar
1 vote
2 answers
202 views

Tiny Magnet Sensor Switch

I know just enough about electronics to do the occasional Arduino or Raspberry Pi project, as long as I don't have to understand too much of what's going on. I am a software guy who dabbles in ...
Faris's user avatar
  • 13
1 vote
1 answer
593 views

Some questions about a low frequency reed switch interface circuit

I need to wire this reed-switch rain-meter sensor to a counter input or to an isolated analog input channel of a data acquisition board. The sensor will be around 30 meters far away from the data ...
cm64's user avatar
  • 2,217
0 votes
3 answers
592 views

Keep a circuit closed after activating a reed switch NO (normally open)

I need a circuit that it is open until I bring near a magnet that closes a NO reed switch for a short interval of time. I need the circuit keep closed for ever. Thanks!
Facundo Cabrera's user avatar
0 votes
1 answer
122 views

Thoughts on this circuit

Here I have a design ( Vcc = 12V ) where relay gets activated whenever reed switch gets closed. I want to activate the relay after a delay of about 2 to 3 seconds from the instant reed switch gets ...
Frank Donald's user avatar
2 votes
1 answer
2k views

Reed switch melting closed in simple LED circuit -- What resistor to use?

Made a simple circuit with a reed switch, wall power source and LED strip (for a bathroom occupied sign). Worked as I’d hoped at first. But, after a while, THE REED SWITCH MELTS CLOSED--leaving ...
Bryant Smith's user avatar
0 votes
1 answer
129 views

can you explain me the working of this circuit in detail? [closed]

this circuit is a occupancy light circuit i want to know the working of the transistor regarding base,collector and emitter in the transitor
Santosh Divakaran's user avatar
8 votes
3 answers
8k views

Why is this reed switch / solenoid circuit not working?

The (normally open) reed switch should close by waving a magnet across it, completing the circuit. The 6v solenoid lock should pull inwards allowing the door to be opened. When the magnet is removed ...
Dominic Edwards's user avatar
0 votes
2 answers
3k views

Multiple switches to independently control a light

I am looking to create a simple circuit to control a couple LED light strips inside a cabinet using two reed switches that turn on the lights if either or both doors is open and the lights to be off ...
CampSoup1988's user avatar
0 votes
2 answers
288 views

what does this mark mean on reed switch?

I have some used reed switches with no datasheets. all of them have a black mark on one side. I want to know what does this mark mean?
Hadi Barak's user avatar
0 votes
0 answers
71 views

How to connect PBI to detect an open door

What's the best way to connect a wired magnetic contact stripe [edit: a "reed switch"] to the door, in order to detect whether or not it's open. I'm not interested in a wireless one, I'm building all ...
Elazar Leibovich's user avatar
0 votes
1 answer
901 views

How can I calculate the hysteresis of Reed sensor?

As question says, I want to calculate the hysteresis of Reed sensor and I don't know how. As I seen in Reed sensor's documentation, hysteresis may be x/y, or the difference between x and y, and I'm ...
Linksx's user avatar
  • 57
1 vote
2 answers
416 views

Hamlin Reed Relays for Audio: Sink or Source?

I'm building a small stripboard audio switchbox using some hamlin 5v reed relays (HE3621A0550, mouser link here). A small SPST momentary switch activates the relay. Wondering if the best practice is ...
user149482's user avatar