Hi all,
i have doubt that whether arduino duemilanova analog input pins can read a volatge in range of +10V to -10V ?
If so which pins can read them?
If not what is the range of analog input voltage they can read??
You ALWAYS have to condition signals for an ADC, be it alone to protect the inputs.
To ask for a +/-10V ADC is -- odd. This is something you generally design youself to fit to your application.
The Arduino ADC can cope with 0 to 1,1 V (this is very precise!), from 0to supply voltage (there are reasons to use this in a lot of cases!), and from 0 to an external reference voltage.
If not what is the range of analog input voltage they can read??
0 to chip's positive Vcc (usually +5vdc). Any higher and a voltage divider is needed. Negitive voltages not allowed, so some kind of external op-amp with an offset adjust needed to 'raise' voltage to stay in the allowed 0-5vdc range.
Lefty
Just to expand on what retrolefty said.
I assume you have some separate bit of electronics that gives you an output of -10 to + 10V relative to its ground.
You want to measure that with an Arduino which needs between its ground and 5V at an analog input.
Well, assuming that:
- The ground connections of the Arduino and this other thing are not connected in anyway - e.g. by both being powered from the same USB hub or both having an earthed ground. If it works from batteries, then you are fine.
- You have access the the negative power supply of this other kit.
You could use the negative supply of the other kit as its 'logical' ground giving you a voltage range of 0 to +20V which you can reduce with a potential divider (2 resistors - google it).
Having said all that, get it wrong and you'll break something, so make sure that you understand what you are doing before going further, and don't blame me if something goes pop!
Good luck - Simon.
So, frankwilliam, let us know a bit more about what you are trying to do so we can help you out.
Engineers are naturally cautious - electronics does not lend itself to hacking.
Having said that, I have a friend who scares the hell out of me doing really stupid things with electronics - massively overdriving transistors, virtually no design other than vague ideas from forums and he does get away with it a remarkable amount of the time. I have tried to make him at least apply V=IR and P=IV but he's to impatient.
Needless to say he destroys a lot of components. Electronics 'Hacking' seems to be a new thing - to me at least - anyone else know people like that?
Si
(rasies hand sheepishly) NPN switching transistors are cheap and make a neat popping sound. Why do math when it's easier to just jam another one in after you pick the silicon bits out of your corneas?
I should post the "design" (lampcord and wall switch) for the cannon driven by electrolytic cap explosion I built years ago.
ANYWAY, this is not really that far off from the automatic gain control thingie I'm working on, basically driving the gain by using a PWM output and a capacitor. I'll crosspost if I get a good solution. I'd say the chances are roughly as follows:
50% good solution, 25% electrocution, 20% "incediary mishap", 5% creation of a naked singularity. All in all, those are odds I can live with, and so can most others outside of a certain radius.
very good!