Also I'm pretty sure I can do this with transistors, so far nobody has told me why I can't.
At the moment I just want to know how to wire a transistor in a breadboard, I am not to familiar with circuitry, and the idea of ground.
You can do it with transistors! 6 of them per motor, in a configuration known as a H - bridge.
Mark
Why can't I do it with two per motor then?
colonelhomer815:
I just bought a set of jumper wires, a 4 pin connector, an AD-01 breadboard, I've done a little experimenting and I am still not sure how to use them, I will post more information shortly but I can really do with advice on how to use these transistors.
In my opinion you're wasting your time (and ours) unless you find out what voltage and current you're trying to control. You need to get a meter and measure the characteristics of the circuit you're trying to interface to. Without that information we have no way of knowing whether you need transistors, or whether the ones you have got would be suitable. It's been said before, but worth repeating: if the circuit needs less than 40mA and 5V to operate then the Arduino could drive that directly.
You need to understand the electrical characteristics of the circuit you're interfacing with before you can design the circuit to interface to it. This is fundamental.
Why can't I do it with two per motor then?
Because in the case of a transistor it is not just an on/off switch. When the transistors is ON the current can only flow in ONE direction. Start drawing things out to see for your self or go take a look in the wiki!
Mark
Could somebody just tell me how to set up a transistor on a breadboard please.
see using a transistor to control a motor in the playground.
Mark
Does one of the transistor pins need to be connected to a pull-down resistor connected to gnd?
colonelhomer815:
Why can't I do it with two per motor then?
Of course you can, ignore the folks above, they don't understand how this
thing is wired.
The way it must be configured is EITHER:
The batteries form two 3V supplies, a +3V supply and a -3V supply. All the motors
get one wire commoned to the 0V midpoint of the battery pack. Thus you only need to
switch one wire for each motor, so two transistors will do - a half-H-bridge.
OR
The control box merely generates signals, doesn't switch the power, and there's a controller
PCB in the unit somewhere. Again this doen'st require 4 transistors per motor!
I suspect te former as its cheaper. You need to measure the current that flows when
one of the motor control wires is connected to V+ or V-. If that current is 100's of mA
then its the motor current directly. If its microamps then its logic signal.
OK so I will try and sort this out just a little bit.
Did some digging and as Mark suggests it is a split power supply.
There is also a usb board to control it.
There are P605's on the board and a little digging came up with the datasheet.
So yes it can be done with just 2 .
AOP605.pdf (579 KB)
Why can't I do it with two per motor then?
Simple and sweet, it probably won't work as you think. Perhaps you should explain why it should work, then the issues can be pointed out which won't work. Ebay has some inexpensive h-bridges that should work for your arm (one per motor. You could also use two relays like in the picture below to control a single motor. There are also setups that use a DPDT relay and a transistor per motor. You might consider starting out with relays instead of transistors if you don't understand the h-bridge concept. below is a relay board that might work for your project.
