How can I make a low-frequency oscillator with a relay (or more ?)

A project log for SPDT16: 16-bits arithmetic unit with relays

Let's imagine I could get about 200 SPDT relays. Of course I would know what to do with them :-D But will 200 be enough ?

Yann Guidon / YGDESYann Guidon / YGDES 05/01/2016 at 06:555 Comments

The multiply/divide mode of operation will require a multi-cycles sequence, hence some scheduling. I think I know how to make the logic part but... where does it get the synchronisation signals from ?

In the quare-root relay calculator, the sequences are generated with an electric motor and a cam. I don't want this. My best bet so far is a ring oscillator (3 relays?) with very large capacitors (I got that in stock, 15000µF is easy to find anyway).

Start/stop is as easy as inserting a SPDT in the ring to stick one coil to 0V for example. Once the start pulse is sent, this relay should be latched and the ring starts to oscillate. The "end condition" will release the control relay which will open the ring.


In theory.

Yes I know, I should have googled that question before posting here. Shame on me.

Only one relay is necessary but a large capacitor is needed (2200µF?) and I'll need other relays (in series with the output ?) to drive the bunch of other coils to control.

I'm so lazy to make the diagrams though :-/

Now that's a good hint:

This "relaxation" version short-circuits its own coil, bad idea. But it gives me another idea ;-)

It could work...

Now, the trick of reinjecting spikes in other coils gets... interesting. Is it going to be a new sport/puzzle/game of this project ? :-)

Update : see Bad vibes


marco wrote 01/07/2021 at 22:43 point

I made it! without any fake load!

It's only require 2 relays, 1 resistor,1 capacitor and an optocoupler...

maybe i post the schematic?

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Andrew Starr wrote 05/04/2016 at 08:58 point

How about a PC fan motor with rear-earth magnets on the blades, spinning under a reed switch? :)

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Yann Guidon / YGDES wrote 05/04/2016 at 09:04 point


no :-)

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Eric Hertz wrote 05/02/2016 at 00:44 point

one relay, connect its coil through its Normally-Closed contacts == fun for the whole family and schoolyard, and an oscillator as well :)

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Yann Guidon / YGDES wrote 05/02/2016 at 00:48 point

yep, that's the consensus I have found on the web :-D And this is what I have figured out with the above drawing.

Working with one technology makes you close-minded, I have been working with MOSFET, thus doing a ring oscillator sounded obvious...

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