Help needed with wiring on piface

Are you wanting to keep the original switches or control them in parallell via the Piface?

There are a number of ways you could physically connect a Piface to your circuit,  you could use the two relays that are on the Piface board to take the place of the 'M1' , 'M2' switches, and two of the open collector outputs for the 'left', 'right' motor

If you need the actual wiring connections, just say.

Colin

Hi Colin thanks for having alook into it.

Yes i would like to control it via the piface and if you know the actual wire conections that would be very appreciated.

I haven't forgotten you Steve, will get back to you sometime this week.

Thanks

OK drawing to follow, but for the moment a word picture of the connections required.

First things first, I'm assuming, you for the moment, just want to duplicate the control layout you have at the moment, I've not seen one of these kits in person so I'm just going by what you've provided and vague descriptions on the net.

I'm a little confused with the diagram for S3 left and right, which i assume is for the forklift up and down, as the drawing shows they can both be closed together which would short everything out - not good.

If you at some stage decide to ditch the current control box, the Pi via the Pi Face would be able to control everything more efficiently and possibly even introduce speed control, and later on predetermined actions, such as bump into something and it spins around to get away from what ever it bumped into.

With the control box in place and wiring the Pi to that, the connections would be.

Control Box connector    PiFace

M1 Motor                      -> K1 centre terminal (2)

Battery Positive**           -> K1 terminal 3

Battery Negative**          -> K1 terminal 1

M2 Motor                      -> K2 terminal 2

                                        Wire K1 terminal 3 to K2 terminal 3

                                        Wire K1 terminal 1 to K2 terminal 1

Ground wire                  -> First terminal on left side with relays and terminals facing towards you. (Unfortunately there is no component designator on the PiFace schematic or PCB layout that I can see

There are two batteries, you will need to trace which battery is the upper one and which is the lower. The batteries are wired like this so that you can have the left motor go forward while the right motor is going backwards and they can use cheaper switches.

** With the two batteries there should be a positive terminal connected to the negative terminal of the other battery, this is ground. If you can't see them physically connected you will need either a multimeter or an LED or 3V light bulb to find the connections.  The positive connection to terminal K1 3 is from the positive terminal of the battery that is NOT connected to the other battery negative, similarly the negative terminal to K1 terminal 1 is from the battery that is not connected to the other battery positive.

This just leaves connections to SW3.

You should also be aware that as it stands at the moment, when the battery is connected the robot will move forward.  If you decide you can do away with the control box and have the Pi -> Piface control the robot directly, this problem will be solved easily and some rewiring at the Piface will need to be done. You will then need to decide if you want to purchase a motor driver chip such as an L293D or press IC3 on the Piface into use.  If you select IC3 you will need to write more code than if you use a an H-Bridge chip. Of course if you don't want the motors to go backwards, you won't need the H-bridge and IC3 will do fine.

Hi Bodgy i realy appreciate all your doing.

Yes the M3 motor left eight is to make the fork lift go up and down.

Pictures of the wiring would be fantastic if you get time.

Thanks again,