Hi all,

I see circuit diagrams with the look and feel of the attached (from Wikipedia) and wondered which tool is used to create such?

Supplementary question: what tools are recommended to the hobbyist?

I would guess that 5v goes to the common pin and then you apply that to each of 4 Arduino pins when each switch is closed.

You would want to have each pin pulled low the rest of the time, so they don't float.

Seems to me it's just 4 of these.

But I may be wrong.....

Not mine no, but this is brilliant

so i bought two 5 volt wall wart power supplies

Have you measured the voltage? Some of them are really crap i.t.o delivering what they say, and the usb must be within 4.75 and 5.25VDC (from memory, don't quote me on the figures) so you might like to be sure.....

(I have a wall wart with a switch for various outputs which gives something like 5 when it says 3.5, and 8 at 5 and blah blah...)

I am supplying an arduino with an 8V power supply through the concentric plug.  Is it OK,  to have the ground pin of the arduino connected to the negative side of this power supply ?

I thought the neg of the plug was the ground?

That's a shame... suggest to her that every home should have one anyway, and it'll be a home item not a science item. 

Btw, your Fritzing diagram the other day showed you had the power hooked up with + and - reversed... I hope that was a mere Fritzing error not a real error? I've never hooked a servo up with the polarity reversed, but I suspect it's bad for it.

mod one of the thumbsticks to give it a bigger handle

I'd be concerned about mechanical damage though... extra leverage + exuberant kids = bad combination, Taffy

You need to answer that question yourself by looking at the maker's spec sheet and providing whatever voltage it says there.

Do you have a multi-meter?

I'm pretty sure there's a question in there somewhere but I don't see it.... 

Yes but you have them in a holder thingy according to your photo-1 from the other day. That will connect them + to - inside the holder, known as "in series" and the voltages add up. So that thing will be putting our 6 x 1.5 = 9v nominal.

It may even be more, if those fresh batteries are more than 1.5 out of the packet. So yeah, you may well be putting too many V's into the motor.

Thats why you can buy a servo to accomplish the same thing.

Seems to me that this is a project to basically build a servo from first principles....

You don't necessarily need a shield, but you will need something to do the motor reversal. So you could use a 298 chip on the breadboard. I've used a MotoMama shield which uses a 298 but the 298 has a huge voltage drop and you need to counter that with your power supply.

Better would be a controller like Pololu's 2130.

Either of those controllers uses PWM. So based on what IR signal you read, in an "if", you control the appropriate arduino output pins to send the appropriate signals to the controller pins, and they take care of what goes out to the motors in terms of polarity (direction) and voltage (speed).

You need to be more specific than that with a question: what voltage do the servos require?- usually 4.8 to 6V but check the maker's specification sheet. Then what voltage do those batteries provide... then you can answer your question yourself. I hope you have a meter, and can check the voltage of the batteries? If not, you really really need one for this kind of work

The word "power" has a specific meaning and is volts x current (amps), although I suspect you mean volts. As long as the current the battery can supply is more than the motors require, and the voltage is in the range required, you should be ok.

Battery provides too high a voltage and boom.
Battery provides too low a voltage and probably motor wont work.
Battery provides too low a current and I'm not sure... might damage the battery by trying to draw too much, dunno
Battery provides too high a current, no problem because devices only draw what they need.

PS... with limit switches I guess you could just read them like in this sketch and when a switch is closed have a servo.write command to one position, and to another when it's open. Eminently doable with an if testing the buttons' states.

Ah ok, so a basic l-r-u-d thing could suffice?

That big joystick from RS looks like a gear-lever from an 18-wheeler tho: there must be something smaller yet robust and not costing over e100 a pop