Science Buddies: "Ask an Expert"

Originally, we planned to use a Reed Switch as the main sensor in our design. The problem is that in my country, it is extremely difficult to find Reed Switches in local electronics stores, and online delivery is slow and unreliable. We also tried looking for old devices to salvage the Reed Switch from, but most of the devices available to us either do not contain one or require complicated disassembly.

Because of this, we are stuck. We understand the idea of how the Reed Switch works and why it is useful, but we simply cannot access it easily.

My question is:
What are the simplest and most accessible alternative components that we can use to build a device with the same basic functionality as a Reed Switch?
We are looking for components that are easy to find in old electronics or that can be replaced with common household items, if possible.

Thank you so much for your support.

Best regards,
[Abdelrahman Sawy Salama]

Moderator note: Some related projects:
https://www.sciencebuddies.org/science- ... itch-motor

https://www.sciencebuddies.org/science- ... meter-work

https://www.sciencebuddies.org/science- ... from-waste#

Hi!

Here are some main components that you can use for a more DIY version of a reed switch:

- small copper pipe: the spring/wire will make contact on the inside of the pipe, and the pipe will serve as one “electrical terminal”

- a steel spring or tight spool of steel wire: will be attracted to the magnet to close the circuit by touching the pipe

- rare earth magnet (neodymium) : to cause the circuit to close (you can find this from taking apart old electronics such as speakers, but most stores sell them so that would be a better option)

- plastic canvas (mesh sheet): to insulate the spring from touching the pipe when the magnet is away/the wire is not in contact with the pipe


These instructions should give you more details into how to use the components to put the reed switch together: https://www.instructables.com/Quick-and ... ed-Switch/

Let me know if you have any more questions!