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1  Using Arduino / General Electronics / PNP transistors... how to use them? on: May 17, 2011, 05:48:52 am
Hello all,
I understand how a NPN transistor works and what it does, but I can't figure out how to use a PNP transistor and what it does. At first, sorta due to only having really basic electronics at school, I thought it did the opposite of a NPN and when the base was low the output would be high and vice versa. But after some research this doesn't seem to be the case. I tried using the Java circuit sim/visualiser/thingymajigy to help explain it but I'm still confused. Could someone explain what it does please?

Thanks in advance.

edit: I want to make a really really simple intervalometer for my camera, but do not have any NPN transistors handy.
2  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: May 10, 2011, 05:54:39 am
Too channel the heat away from the pad underneath, can I solder on a piece of copper wire? or would some sheet metal be better
3  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: May 09, 2011, 01:37:35 am
The ICs are mega tiny, is it ok to solder a short length of magnet wire to the ic then solder normal hookup wire to the magnet wire?
4  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: May 08, 2011, 06:46:00 am
Just to make sure, but I dont have to use any resistors with the i2c chip right? Just connect motor and flyback diodes then i2c connections and power sources?
5  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: May 06, 2011, 07:12:05 pm
Thanks, I assume that I still need to have flyback diodes as the datasheet doesn't seem to say anything about flyback protection. Instead of using schottky diodes, could I just use rectifier diodes like the IN4004?
6  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: May 06, 2011, 06:25:05 am
I've since purchased the motors and a cheapo multimeter, however as I realised if I purchase SN754410s from ebay, I will not be able to purchase other neccessary components, could I use 2 of these? http://focus.ti.com/docs/prod/folders/print/drv8832.html. I realise that they are surface mount components, but I'm up for the challenge.
Also, with the i2c version, is it controllable through the wire library?
edit: skimmed the datasheet of the i2c version and it seems that all is needed is to send values throught the wire library?
7  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 27, 2011, 01:13:15 am
Thanks for the help, I'm going to be making an IR remote car first, once I get all the stuff.
8  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 26, 2011, 12:30:00 am
I don't really understand what you meant by this
Quote
just run all for IN lines to your Arduino
?
9  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 25, 2011, 08:16:24 pm
Thanks for the help, I actually save around 5~6 dollars because of the shipping if i buy the solarbotics ones.
edit: is there a higher resolution copy of that diagram?
edit again: over here for anyone eles who might need it http://www.google.com.au/url?sa=t&source=web&cd=1&ved=0CEQQFjAA&url=http%3A%2F%2Fwww.societyofrobots.com%2Fmember_tutorials%2Ffiles%2FDC%2520Motor%2520Driver%25201A.pdf&rct=j&q=1A%20DC%20motor%20driver&ei=AR62TfKiBJKCvgPIrdGnDw&usg=AFQjCNF36Of5vR_u9iGYWihcTnu7iE-qvw&sig2=Op3xLjUcIzkrxPPgSzlijA&cad=rja

edit again again: I'm assuming if i get 2x 1A diodes and wire them in parralell they will equal to a 2A diode?
edit again again again: Can I use BC 548 transistors instead of BC108Bs?
10  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 25, 2011, 04:32:08 am
Would http://cgi.ebay.com/Low-Cost-Gear-Motor-2-Pieces-DC-robot-chassis-/280581321548?pt=LH_DefaultDomain_0&hash=item4153f3334c#shId be suitable? as it is half the price of the solarbotics gearmotors and I'd like to keep this cheap being a jobless teen.

edit: Also if I don't purchase a motor shield how would I go about implementing flyback protection? (I understand that if It only travels in  a single direction you only need one diode across the motor contacts, however with bidirectional control, this wont work?).
11  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 24, 2011, 11:05:35 pm
What motors + driver would you recommend for a small car?
12  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 24, 2011, 09:17:11 pm
As there are no electronics shops near me (I blame DSE for dropping hobbyist electronics), I have not had a chance to buy one. I plan on getting one when/if i get a motor shield.
13  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 24, 2011, 08:23:58 pm
Is stall current the current it draws when it is stopped from moving? Could I just add a resettable fuse so it never draws over a set amount of amps? (This is what was done with a r/c lama to stop it from frying the electronics when the blades where hindered from moving.) I want to use these as they're the only pair of motors that I have on hand.
14  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 24, 2011, 08:59:11 am
Would that require a multimeter? / Is the stall current in  http://www.aero-nuts.com/images/CCF20080505_00000.gif the one required?
15  Using Arduino / Motors, Mechanics, and Power / Re: Is this motor shield sufficent for controlling 2 (formerly) rc heli motors? on: April 24, 2011, 08:51:50 am
Thanks for the reply, but the motors I have are just plain brushed motors. So no brushless escs are needed. (I am aware that r/c hobby grade brushed escs exist, however I am aiming for as cheap as possible and I have not had any luck finding a bidirectional esc that is cheap as well).
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