# Is there such a thing as a switch that can be actuated automatically?

I'm interested in a toggle switch that can be toggled without user input. That is, the physical state can be toggled electrically. It would need to incorporate some sort of motor or magnetic actuator. My google-fu is weak in this area, and I haven't been able to come up with the correct combination of search terms.

Note that I'm not talking about a relay; I'm talking about a normal toggle switch:

Except that it can be toggled without user input. As in, the lever physically moves. Like a "useless machine" except that the mechanism is internal to the switch.

• what is the toggling rate ? What device at what power level is to be connected to the switch ? – rahulb Mar 13 '14 at 17:34
• What I've seen in practice is that the mechanical "switch" part is external to any electrically controlled "switch". For example, there may be a master mechanical "kill switch" which is wired in series with any electrically controlled switch such that if any switch goes open the system will shutoff. On the other hand, it's not too hard to wire a relay to be controlled with either an electrical signal or the state of a switch. You could get creative and add a circuit breaker and overload it in a controlled manner to get the same effect. – helloworld922 Mar 13 '14 at 17:48
• @helloworld922 Yes, but then you loose the indication aspect of the toggle switch. The toggle switch not only switches the electrical signal, it also indicates the state of the signal to the operator. Of course, indication can be done with something like an LED next to the switch. – Nick Alexeev Mar 13 '14 at 17:51
• Yes, this has been answered on this site before. Search for more information. omron.com/ecb/products/sw/41/a8g.html – HL-SDK Mar 13 '14 at 18:06
• youtube.com/watch?v=Z86V_ICUCD4 – Scott Seidman Mar 13 '14 at 19:52

What you are looking for is a rare beast. Honeywell produce a toggle switch (2 position and 3 position) that can be remotely reset by removing the holding current - this releases the magnetic force exerted by a small solenoid and the switch returns to off or centre. This may do what you want but, I suspect that you would want to be able to toggle it at will remotely: -

Why can't you easily find one that can toggle in both directions? Complexity and performance expectations leading to unfeasible cost and therefore NO foreseeable market is the main reason. Hey it was hard enough to find this one let alone one that can be operated at will in both directions remotely.

• That is indeed very close. Maybe as close as I'm going to get. Thanks! – Mark Mar 13 '14 at 18:17
• The price of these switches is steep, though. That is probably because these switches are MIL spec (and a living fossil too). – Nick Alexeev Mar 13 '14 at 18:19
• Look at HL-SDK's comment- those switches are relatively reasonable ($15 USD). – Spehro Pefhany Mar 13 '14 at 18:23 • Yeah but they still don't switch in both directions remotely. – Andy aka Mar 13 '14 at 18:28 You can get a slide potentiometer that is motorized. It has a 100mm stroke, which you'll want to restrict to maybe 15-30mm, but with a suitable knob, and a microcontroller you can emulate your motorized switch. You can even provide feedback and make it feel like a snap action switch. When it's moved away from one position, it pushes back a little bit, until it's moved past center, then it accelerates to the other position and stops. You can define your own spring constant for the snap action, up to the force of the motor control, anyway. It would take up a lot of space, but might fit your needs. • I will second this. Motorized potentiometers are rather common, can be obtained relatively cheaply and available in both linear (as depicted) and rotary (more compact and possibly more convenient) form. – oakad Mar 14 '14 at 1:01 • @oakad Interesting, I suppose if you mount the rotary motorized pot with the shaft parallel to the panel, then attached a rod to the shaft at a right angle, you'd have a very switch-like motorized device. – Adam Davis Mar 14 '14 at 17:30 The closest thing that I can think of are Syndyne SAMs (Stop Action Magnets). They are designed and primarily used for organ consoles, where the stops need to be set manually by toggling the SAM, but where their states may also be saved and recalled at the push of a piston (small button under the keyboard). I'm not going to repeat the specifications because all of that can be found on the website I linked to, but basically each has an electromagnet to pull the switch on when powered, and another electromagnet to pull the switch off. They operate very quietly and smoothly, but still have a gentle tactile feel. Syndyne also makes Solenoid Draw Knobs, which accomplish the same task in a slightly different fashion. Last I checked, the SAMS cost somewhere around$30 to \$50 each, though I'm not sure if Syndyne sells to individuals. They can sometimes be found on eBay, and some organ salvage businesses might have some to sell as well. I'm not sure about the SDKs.

Also, I realize this post is old, but perhaps someone might still find this info useful.

I couldn't find anything online either, but I did find a patent that was close: http://www.google.com/patents/US20110316655?cl=en

It seems to be pretty recent too. Their figures don't look like a typical toggle switch, but reading the abstract and skimming the article makes me think they are trying to do the same thing.

Searching for "Magnetically Actuated Switch" and similar terms seemed to get me a little closer, but searching along the lines of "Electrically Actuated Switch" keeps pointing to relays and tutorials about switches in general.

Also, there appears to be magnetically held switches, but they don't actuate. Hopefully this helps a little bit at least.

It might be possible to make one with a solenoid, but that sounds like a lot of work. You could fake it with a momentary toggle switch that returns to the center, and put an LED above and below it, and light up the one coresponding to the virtual switch position, but that's not quite the same. It would be an interesting UI though.

You could attach a knob and encoder to a stepper motor, and make a rotary switch, or use an analog feedback servo http://www.adafruit.com/products/1404 instead of a stepper and encoder

It's called a relay, normally. There are latching versions that can act like a toggle switch. Though there are various types of solid state switches that may solve the problem as well. Without more information about voltage and current levels, control signals, etc. it's difficult to make a specific recommendation.

• I'm looking for what a layman would call a switch, i.e. it has a lever that can be either physically toggled with a finger, or electrically toggled by, for example, a microcontroller. – Mark Mar 13 '14 at 17:34
• @Mark Toggle switch, or rocker switch, or momentary switch? It would also help if you describe why you need such actuated switch, and what you're ultimately trying to achieve. At the moment, the question is not too clear. – Nick Alexeev Mar 13 '14 at 17:43
• OK, question was not clear, I see it has been edited to be more specific. – John D Mar 13 '14 at 21:18