Hi,<br>I just ordered a Uno, i think it will suffice. <br><br>Martin, I'd like to replace my pot with an optical sensor if it's quieter. Only i've never used one. How does it work? How do i put this in the pedal? <br>
<br>Looks like i'm not nearly through asking questions about arduino...<br><br>Pierre<br><br><div class="gmail_quote">2011/4/10 Martin Peach <span dir="ltr"><<a href="mailto:martin.peach@sympatico.ca">martin.peach@sympatico.ca</a>></span><br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Probably the thing will read quieter if the pots are lower resistance. The data sheet for the atmega microcontroller used in the arduino says hat the impedance of the analog source should be less than 10kOhm. Also putting a .1uF capacitor from the analog pin to ground will smooth out glitchy noise. (And averaging a few values in software helps too.)<br>
<br>
The arduino can send its data as MIDI by using two 220 Ohm resistors (one from 5V to MIDI pin 4, the other from TX to MIDI pin 5, ground to pin 3) and a baud rate of 31250. That can eliminate noise caused by the USB connection, but you have to program the MIDI messages yourself instead of using pduino, as well as powering the arduino from a battery (quiet) or AC adapter (noisy).<br>
<br>
I have built a MIDI pedal that uses an optical sensor to detect the pedal position. It is much quieter than a potentiometer.<br>
<br>
Martin<div class="im"><br>
<br>
On 2011-04-10 10:56, Pedro Lopes wrote:<br>
</div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;"><div class="im">
You can filter out some noise if that happens. I have done several<br>
arduino projects (namely public installations or sculptures with<br>
sensors), one thing I learned is that you can always filter the (some)<br>
noise, by ignoring some values and so forth.<br>
Another fun aspect is that in public installations whenever I connected<br>
the arduino to the AC power outlets (instead of battery) the noise was<br>
much higher. (which makes sense, since AC powers of houses, steet, etc..<br>
are actually noisy (have you ever noticed that AC induces noise on most<br>
laptop on-board sound-cards - due to ground loop and so forth) )<br>
<br>
>use i wanted to use a pot to control a delay length (you can hear<br>
gliches if the delay length jumps from one value to another rapidly).<br>
But don't panic about it, its workable. You can defined thresholds, and<br>
if it varies withing a certain range you will not consider as the pot<br>
has moved, if you do not have noise: even better. But electricity is not<br>
perfect, components are definitely not perfect either :)<br>
<br>
Best,<br>
Pedro<br>
<br>
On Sun, Apr 10, 2011 at 3:50 PM, Pierre Massat <<a href="mailto:pimassat@gmail.com" target="_blank">pimassat@gmail.com</a><br></div><div class="im">
<mailto:<a href="mailto:pimassat@gmail.com" target="_blank">pimassat@gmail.com</a>>> wrote:<br>
<br>
uctuate a little"? This could be anoying if they fluctuate too much,<br>
because i wanted to use a pot to control a delay length (you can<br>
hear gliches if the delay length jumps from one value to another<br>
rapidly).<br>
<br>
<br>
<br>
<br>
--<br>
Pedro Lopes (MSc)<br></div>
contact: <a href="mailto:pedro.lopes@ist.utl.pt" target="_blank">pedro.lopes@ist.utl.pt</a> <mailto:<a href="mailto:pedro.lopes@ist.utl.pt" target="_blank">pedro.lopes@ist.utl.pt</a>><div class="im"><br>
website: <a href="http://web.ist.utl.pt/Pedro.Lopes" target="_blank">http://web.ist.utl.pt/Pedro.Lopes</a> /<br>
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<br>
<br>
<br></div><div class="im">
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