Powering a motor with remote AND switch?

[johncarpenter]

Hello everyone, long time reader, first time writer here.

For my next project, I want to power a motor through the normal IR remote control system, but also through a switch on the vehicle itself. Does anyone know if this is possible?

To do this, I'm guessing that I would connect the motor cable to the output of the IR receiver as normal, and then add an extension cable from the switch to the same motor cable. I'm a bit worried that I might fry some of the electronics, so I wanted to ask here before I try anything out.

I've tried searching for it, but did not come up with any answers. Does anyone know if this is possible, and safe?

Edited June 16, 2020 by johncarpenter

[mindstormsboi]

It seems like no one can answer your question (sadly I can't either), you might want to try asking here if you don't get a response soon enough.

[doug72]

Why not just use the pole reverser swith on the the remote control ?
The little blackslide switch.

[suffocation]

Not sure it's covered here but it's worth having a look: https://www.sheepo.es/2015/05/tips-and-curiosities-power-functions.html

[ben20]

4 hours ago, johncarpenter said:

Hello everyone, long time reader, first time writer here.

For my next project, I want to power a motor through the normal IR remote control system, but also through a switch on the vehicle itself. Does anyone know if this is possible?

To do this, I'm guessing that I would connect the motor cable to the output of the IR receiver as normal, and then add an extension cable from the switch to the same motor cable. I'm a bit worried that I might fry some of the electronics, so I wanted to ask here before I try anything out.

I've tried searching for it, but did not come up with any answers. Does anyone know if this is possible, and safe?

Give it a try! All the electronic components are tested and retested in all worst case scenario's. Also protectors against shortcut, overheating, etc are used

It's made most for kids, so you can imagine Lego won't risk a claim of a burned house or other electric danger that comes with wrong placed electronics

[johncarpenter]

7 hours ago, Doug72 said:

Why not just use the pole reverser swith on the the remote control ?
The little blackslide switch.

It is not just about reversing the direction. I want to have the same motor driven by remote control, but also by a switch on the vehicle itself. I'll post the project soon, to explain how this is supposed to work.

5 hours ago, ben20 said:

Give it a try! All the electronic components are tested and retested in all worst case scenario's. Also protectors against shortcut, overheating, etc are used

It's made most for kids, so you can imagine Lego won't risk a claim of a burned house or other electric danger that comes with wrong placed electronics

Thanks, I guess I'll try it tomorrow and report back. I hope nothing will go up in smoke!

I was planning to fit another M motor in there, to have this switch operated functionality. However, if I can avoid that, and drive the same motor from the two sources, I would very much prefer that solution.

[Saberwing40k]

So, you want a model where you can control the model remotely, or use a switch? I don't think that's actually possible with PF connectors. I may be wrong, though. 

[dr_spock]

You could use two PF switches since LEGO doesn't make a DPDT switch.  Put one switch between the PF IR receiver output and the motor and the other switch between battery and motor.  That way you can isolate unwanted current going to IR receiver's motor driver IC outputs when you're running the motor on the direct switch. 

[Saberwing40k]

I don't think that works. If I recall, the PF receivers will actually bypass the switches. Sariel actually showed that you can daisy chain receivers by attaching the connector wire to the output of another receiver, and it will work no matter what.

It's the first tip in this vid. It's cool, but can also be inconvenient.

[BusterHaus]

12 hours ago, dr_spock said:

You could use two PF switches since LEGO doesn't make a DPDT switch.  Put one switch between the PF IR receiver output and the motor and the other switch between battery and motor.  That way you can isolate unwanted current going to IR receiver's motor driver IC outputs when you're running the motor on the direct switch

This is the correct solution.  Just remember to have both switches in the middle (off) position before selecting a direction on one of them. 

5 hours ago, Saberwing40k said:

I don't think that works. If I recall, the PF receivers will actually bypass the switches. Sariel actually showed that you can daisy chain receivers by attaching the connector wire to the output of another receiver, and it will work no matter what.

They may bypass IR receivers, but physical switches are either on or off. Sariel's example (9 minute mark in the video you linked) relies on one of the switches being off to have power going only to 3 IR receivers. 

[johncarpenter]

22 hours ago, dr_spock said:

You could use two PF switches since LEGO doesn't make a DPDT switch.  Put one switch between the PF IR receiver output and the motor and the other switch between battery and motor.  That way you can isolate unwanted current going to IR receiver's motor driver IC outputs when you're running the motor on the direct switch. 

I guess this would work, however, I don't have an extension cable or a second switch to try it with.

Anyway, thanks everyone for the help, but it sounds like this is not so easy. I think I'm going back to my original plan of putting another M motor in there. The functionality will be the same and it will be simpler than having two switches.

[madsen1997]

With the project on built at the moment, I've been using one of the older 9V cables to connect 2 extensions cable running from the switch to the Servo- motor in my build, with that set up I can control the Servo-motor either with PF IR Remote, or by using the switch itself.

It does need 2 extension wires + 1 9V cable at one line, but it does works just fine.

 

Just attached a quick sketch

[johncarpenter]

On 6/18/2020 at 11:47 AM, madsen1997 said:

It does need 2 extension wires + 1 9V cable at one line, but it does works just fine.

Was there a particular reason why you used 3 cables? Just due to the layout of your model, or are they necessary?

By the way, if anybody wants to see what the project was, I've posted it here.