momentary 12v pulse toggles latching relay on/off - solid state switch

momentary 12v pulse toggles latching relay on/off - solid state switch

FAQ: Do you have a 12v momentary contact latching relay or switch that can be toggled on/off?

If you have ever had trouble finding a latching relay that is toggled on/off by a momentary 12v pulse, here is a great solution.

Yes, we have an SSR (solid state relay) 'smart switch' with latching and optional timer capabilities! This unit is a member of our RollerNode™ controller series, and we refer to it as the RSS (Really Smart Switch) because the programmable nature of this unit means it can be used in many different ways.

This product came about because we had a critical need for a momentary contact switch during the development of our remote control system for LED dimming (like the LED strip lighting in the above picture). We wanted a lighting system that would complement our remote control 12v DC motors used for blinds, shades and drapes, using the same remote control system (with the ability to have the extended control by phone, tablet, laptop).

We needed a 12v latch using a momentary contact 12 volt switch that would power on our system, but that turned out to be an elusive item. Double pole latching relays require 2 switches to operate (not what we wanted), and regular single pole latching relays require polarity reversal to operate (not this either). We just wanted to toggle a circuit on and off with a single momentary contact switch.

After weeks of searching for a suitable solution, we were not able to find anything that would suit our exact requirements, so we decided to make our own, and thus the RSS project was born. Then we decided to add an Arduino™ compatible microprocessor to it and make it really smart so that it could be easily adapted to work in other applications that may require a different solution.

From our mission statement, you can see we are big proponents of solar technology, with the hope that we can help reduce our dependency on fossil fuels. So we added an 'auto-off' circuit that kills all power except to the tiny device that watches for the control pulse, resulting in a miniscule standby quiescent current of 0.001 mA @ 12v. It also has an 'always on' jumper, if you need the active CPU mode of operation, using about 20 mA.

With its default factory settings, the RSS simply turns on a 10 amp circuit when it receives a momentary 12v signal on its trigger input. When it receives a second trigger signal, it turns off. The unit has a self-resetting breaker type fuse that triggers at 11 amps and resets at 7 amps. It is also reverse polarity protected.

If that's all you need, then you can stop reading right here and buy it; here's the listing in our online store, just below our remote control version:

12v Really Smart Switches

Advanced Features: A Versatile Control Platform

So what exactly is this device? You could say that it is a fully bootable computer, complete with operating system, solid state hard drive, system memory, and a USB port for program I/O. That's a lot of control power in a small, very affordable package.

But we also added 2 jumpers that can be changed to alter program behavior, so that it did not have to be re-programmed to suit every situation (even though that is easily done via the USB port). If you remove the program jumpers, it will cause the on/off switch to become a very smooth LED dimmer that ramps up to full brightness when it receives the 12v trigger pulse, using PWM (Pulse Width Modulation). When it receives the second trigger impulse, it fades the LED down until it turns off.

impulse latching smart switch motherboard

We also thought that it would be a good idea to add a breakout socket for the Arduino™ Nano™ board we use from Gravitech USA, so that our users could make their own plug-in board, which makes it a very suitable environment for developing prototypes, or perhaps just to use as a learning tool for microprocessor behavior. There is certainly no easier platform than Arduino™ for use as an educational tool.

But we didn't stop there, because we realized it would also be relatively easy to design the 'form factor' in such a way it can also accept all the Nano accessory boards from Gravitech. So yes, you can just plug in all the nice boards that Gravitech makes, from Zigbee to MP3.

Want a remote control jukebox? You can do it all on-board with this Really Smart Switch ...

Then we went really nuts and added another socket to accept our 'MiniMight' motor controller board. With that option, you can control 2 DC motors with full reversing capabilities, at about 1 amp each (continuous). You can run them at a fixed speed, but we added PWM for variable speed operation too. The MiniMight is fully protected against thermal runaway and accidental short circuit, with auto-reset capability.

This makes the unit very suitable for operating small motors to do useful things, like our 12v window and skylight openers. Or, use it for switching relays or solenoids to carry heavier loads.

And finally, we added another jumper that enables parallel operation of the motor control, increasing the continuous current capability to about 2 amps by combining the 2 individual motor channels into a single channel for one motor (still with PWM motor speed control and fully reversible motor capability).

buy programmable impulse latching smart switch in our online store

We sincerely hope you enjoy using these advanced switches; if you have any questions, please feel free to contact us at any time! If you are interested in seeing the instructions for the RSS smart switch, please see our remote control version, it is the same except for the radio remote control add-on system.

Please Note: We do not recommend that you use this device to control large 120v/220v relays for AC mains, without having a professional electrician install this unit properly, according to local and national electrical codes. You risk nullification of any insurance policy you may have, and there can be real danger to children and adults with those voltages.