My next project will be a set of Arduino powered MIDI drum pads connected via the Arduino.
The initial tests with a piezo sensor connected to my Uno, a slightly adjusted version of the code from here to send drum hits and velocity via the serial port, then a little program in Processing to send MIDI notes to Garageband worked very nicely.
But I'm not sure for the full kit what sort of wire I should use to link the piezo sensors to the Arduino: is something like this what I should look for? I'm in the UK btw.
I understood a twisted pair will be less susceptible to interference, and I guess it should be stranded for flexibility - but I'm not sure if that one is too thin. I guess the maximum length between sensor and Arduino will be around 1-2m.
Any info / thoughts appreciated! I have done a fair bit of googling, but the examples I've read just specify "wire"!
That wire is o.k. but it's actually quite thick and won't be very flexible. 7 x 0.1 would be fine but if you're really worried about interference then shielded 2-code, something like this might be good.
A twisted pair is less susceptible to electrostatic interference if it is used as a balanced line. If not a balanced transmission line, the benefit is minor.
It is slightly less susceptible to electromagnetic interference - from solenoids, relays, transformers and large loops of wire, than "twinned" ("figure-8") cable.
Shielded wire is most effective (and shielded twisted pair best) but has higher capacitance, which may be a concern for high impedance signals such as piezoelectric sensor.
But the stuff you cite looks beautiful!
You are not using it to carry any significant current, so the gauge is pretty irrelevant. Flexibility is important.
That's interesting about the capacitance - and maybe I'm overthinking the interference thing.
Speaker wire seems to be very cheap - perhaps I should just get something like this?
I use a lot of:- Rapid 10/0.1mm Equipment Wire 100m | Rapid Online
If you want twisted wire simply take two strands, fix one end in the vice and the other in a drill chuck, take up the tension and give the drill a very short blast. The wire will be good and tightly bound together.
A twisted pair is less susceptible to electrostatic interference if it is used as a balanced line.
Paul - I think you mean less susceptible to electromagnetic interference, because each wire picks up the same interference. Then the common mode rejection ratio of what you are feeding it into, with a differential input will reduce the picked up interference.
By definition electrostatic fields do not induce any interference because they are static. Waggling a wire in an electrostatic field will however induce interference in the wire.
Thanks Mike, I've ordered some of that in the end, looks like decent stuff to have around anyway!
Well if we are going to get fussy, I meant electrodynamic interference - capacitive coupling, which I was distinguishing from electromagnetic coupling.
Speaker wire will probably be OK; I presume the piezo pads will generate a far stronger signal than any common interference.
That rapidonline site is a pest - comes up with a nuisance blocking popup. It is truly frightening what crap websites produce nowadays.
It is truly frightening what crap websites produce nowadays.
I have to agree with that the website is awful, and they do pester by email. But they have good prices in some things like pots and strip board, deliver is quick and the quality is good.