Remote control switch suggestions

[Prawo Jazdy]

I’m making a small electric car for a 5yr old, and want to incorporate a cut off switch. The idea is that I can carry a key fob thingy, and can cut the power from a fair distance away (maybe up to 100m?) if I think I need to stop the car. It would need to be a momentary action switch to match the power switch type from the vehicle, on a low voltage DC circuit.

Any suggestions? There’s a few things online around the £10-15 mark, but I’m worried I might be buying junk.

Cheers.

[GliderRider]

Something like this: Wireless Remote Control Switch DC12V 10A 433MHz Transmitter with Receiver

[steve-V8s]

Would it be better to have something that enables it to run rather than something that cuts the power.

The 433 mhz channels which are used for most of these remote operation things (Including doorbells car keyfobs and a lot more) can be quite busy and therefore subject to interference. If you had an arrangement where the vehicle had to receive a signal from your remote control to proceed it would shut down if suffering interference or going out of range rather than motoring off into the distance.

[Prawo Jazdy]

Thanks for the suggestions. I’m not sure if I can make the switch work so that it needs the signal to operate. Or at least, it is much easier for me to do it the other way with my existing know-how. It’s a nice idea though - I’ll give it some more thought.

The garage switch seems to operate as a latch, whereas the existing on/off button doesn’t latch when you press it, it’s just one press for on, and press again for off.

Is it possible to buy stuff like this from a retailer that seems vaguely reputable, and not just Amaz-baba? I’m not having a dig at the link, as it’s the same with every switch like this I’ve looked at online. It seems Amazon is now flooded with cheap stuff from China, and it is difficult to sift out stuff which appears decent quality. Scores of identical products don’t help either.

[nyt]

I have several of the devices above and they are reliable ( 3 month's ownership ). They have never triggered by themselves or from interference.

My main concern is that the device uses a smallish relay, rated for about 10A. I never run them above 2 or 3 amps. You'd have to use the relay to cut the ignition (if it has one) rather than interrupt the drive to the motor.

This guy covers this device in a fair bit of detail: https://www.youtube.com/watch?v=tkhUR_30o0s.

[Prawo Jazdy]

Thanks for that, I’ll take a look. The power button is part of a controller unit which is much lower current than the motor circuit, so it shouldn’t be an issue I don’t think. If you hit the power button while the chair (and eventually car) is running, it winds the motors down quickly, applies the electromechanical brake and then turns off. I’m hoping that soldering in a remote way of triggering that power button will be the simplest way to achieve what I want.

[nyt]

Prawo Jazdy said:

Thanks for that, I’ll take a look. The power button is part of a controller unit which is much lower current than the motor circuit, so it shouldn’t be an issue I don’t think. If you hit the power button while the chair (and eventually car) is running, it winds the motors down quickly, applies the electromechanical brake and then turns off. I’m hoping that soldering in a remote way of triggering that power button will be the simplest way to achieve what I want.

It may be that the power button is a normally closed (NC) switch and goes open circuit when you press it. That's how emergency stop buttons are usually implemented.
In that case, you would need to use the remote relay to power another relay - a NC relay - and cause that to go open circuit. Install the 2nd relay in line with the power switch.

ETA: Something like this: https://www.amazon.co.uk/MagiDeal-Automotive-Truck...

Edited by nyt on Thursday 8th July 23:19

[Penelope Stopit]

Depending on the voltage, have got a solution

What voltage?

Are there several batteries linked together?

[Penelope Stopit]

GliderRider said:

Something like this: Wireless Remote Control Switch DC12V 10A 433MHz Transmitter with Receiver

Note

The information given above does solve the remote side of the operation

The controller can be programmed for momentary switching

[Prawo Jazdy]

I'm pretty sure the PCB in the controller is running at 5V (the joystick certainly is), but the wires going into the controller are 24V. The power source is two 12V leisure batteries connected together.

[Penelope Stopit]

Ebay search is - Momentary wireless remote control switch dc12v

Most of the remotes on the bay work the same

Need one that will accomplish momentary switching, Chinese list it as - Jog

Jog setting makes the COM and NO contacts when pressing the remote button and breaks them on release of the button



Unit needs 12 volts (pos&neg), connecting a twin cable to one of the two 12 volt batteries will do the job or add a small 12 volt battery

Wiring the remote controller

Supply it with 12 volts pos and neg as above

Link from negative terminal to the COM terminal

Find cheapest Durite latching relay - Durite 0-728-02

Here's one https://www.arc-components.com/0-728-02-durite-12v...



The Durite Latching relay has a mechanical locking mechanism

Wiring the Durite....

Use the same 12 volts supply as what's being used for the remote controller

Connect 12 volts positive to terminal 30

Connect S terminal to the remote controller NO contact

Operation....

Pressing the remote button for a second or two will have the controller switch a momentary negative to the Durite which will connect Durite terminal 56 to 56b and those contacts will remain mechanically closed until releasing the remote button and pressing it again

Obviously the next press of the remote button will connect Durite terminal 56 to 56a and they will remain mechanically closed until the next press of the remote button

---

Use Durite contacts 56 and 56a or 56b as a switch to make and break a circuit that will stop the car

[Prawo Jazdy]

Thanks for such a comprehensive answer, that’s great! Now I just need the time to digest what you’ve written, but at first glance it sounds ideal.

[Penelope Stopit]

You're welcome

This diagram will hopefully help you

[Penelope Stopit]

You'll need to find a lowish current carrying car control circuit to break with the Durite latching relay, there should be one

Post back if there is no such low current carrying circuit that can be broken to stop the car

Durite latching relay contacts are max rated at 25 Amps

[Prawo Jazdy]

Just to update this: I bought one of the Made-in-PRC-pieces-of-tat momentary switches on Amazon. Before buying a relay I though I’d try the idea I had of how it would work. I pressed the switch output wires onto the contacts of the power button on the wheelchair controller, powered the receiver and hit the key fob button... and the wheelchair came to life! Another press and it turns off again. I am very happy.

I really appreciate the description of how to use this remote switch with a relay, but it doesn’t seem necessary in this case - apologies if I didn’t describe the problem well enough.