Linear Actuator 2 button controller

Help & Support Robot Parts
1

Hi, Im completely new here and only have a basic knowledge of electronics. My only experience is wiring electric guitars and amplifiers which I’m fairly confident doing however my knowledge stops there at the moment. I saw another user post a linear actuator project question however I didn’t want to highjack their thread being my first post. Also I think our projects differ slightly, anyway I’m in need of a little help and direction.

The project simply is a linear actuator which I wish to be able to operate from standing in two different positions within the room via two small simple button switches. One switch will extended the actuator then from another position within the room (Approx 5 feet away) the second button switch which will allow the actuator to retract once pressed. I only need one switch to open and the other to close (I don’t need to be able to open and close the actuator from both positions within the room).

I haven’t bought anything just yet until I’m sure I have it all worked out. I’m not too sure which actuator I’ll go for but something in the region of this spec - 12v DC 25W 4A max load 30mm/s 200Nm. My understanding to operate this actuator I will need the following

2 x button switches
2 x 12v DPDT 4A relay switches
2 x External limit switches
1 x 12 DC Power supply

As my knowledge is very limited I’m really not sure if what I am doing is even remotely correct so please flame me down if I’m on the wrong track.

I’m guessing once the “Open” Button switch is pressed it will trigger the relay allowing the actuator to extend without the need to hold the switch. Then once the actuator hits the external limit switch this will cut the relay and stop the actuator travel. Then pretty much the same for the “Close” Button switch but reversing the polarity therefore retracting the actuator?

I’m pretty sure this is a simple circuit however if anyone could add any help that would be great.

Much appreciated
Ikke

2

Hi,

Here is an example of this kind of design with a relay where the reset switch would be the limit switch and the set switch the open or close button. Just make sure that the open and close button cannot be pressed at the same time because you will create a short circuit if you don have a proper circuit design.

Best regards,
latching-relay-rp.png

3

Thanks for your reply. Thats great! Just have a few more questions.

I thought I would need a relay for each button switch but I can run them both through one? Thankfully the switches wont be able to be pressed at the same time due to the location of them so its safe enough.
I also thought I would need two limit switches to essentially reset the relays when opening and closing. Obviously the actuator extending must have the limit switch but what about when its retracting back in, do I not need a limit switch to cut the relay once the actuator has returned back to the start position?

Many thanks again!

4

Sorry I read the circuit diagram wrong the first time. I think I understand now! Also my above post I was thinking of a SPDT and not DPDT, my mistake.

5

Hi,

To answer you second question, you will need a limit switch for both position.

Let us know if you have any other questions.

Regards,