Simple Arduino code: control pitch with a potentiometer. Material required: potentiometer, piezo buzzer, Arduino board, jumper cables.

pot-tone.html

<pre>
<font color="#00979c">void</font> <font color="#5e6d03">setup</font><font color="#000000">(</font><font color="#000000">)</font> <font color="#000000">{</font>
 &nbsp;<b><font color="#d35400">Serial</font></b><font color="#434f54">.</font><font color="#d35400">begin</font><font color="#000000">(</font><font color="#000000">9600</font><font color="#000000">)</font><font color="#000000">;</font>
<font color="#000000">}</font>

<font color="#00979c">void</font> <font color="#5e6d03">loop</font><font color="#000000">(</font><font color="#000000">)</font> <font color="#000000">{</font>
 &nbsp;<font color="#00979c">int</font> <font color="#000000">readTime</font> <font color="#434f54">=</font> <font color="#000000">20</font><font color="#000000">;</font>
 &nbsp;&nbsp;&nbsp;<font color="#434f54">// read the input on analog pin 0:</font>
 &nbsp;<font color="#00979c">int</font> <font color="#000000">sensorValue</font> <font color="#434f54">=</font> <font color="#d35400">analogRead</font><font color="#000000">(</font><font color="#000000">A0</font><font color="#000000">)</font><font color="#000000">;</font>
 &nbsp;<font color="#434f54">// print out the value you read:</font>
 &nbsp;<b><font color="#d35400">Serial</font></b><font color="#434f54">.</font><font color="#d35400">println</font><font color="#000000">(</font><font color="#000000">sensorValue</font><font color="#000000">)</font><font color="#000000">;</font>
 &nbsp;<font color="#434f54">// play tone at that frequency:</font>
 &nbsp;<font color="#d35400">tone</font><font color="#000000">(</font><font color="#000000">8</font><font color="#434f54">,</font><font color="#000000">sensorValue</font><font color="#434f54">,</font><font color="#000000">readTime</font><font color="#000000">)</font><font color="#000000">;</font>
 &nbsp;<font color="#d35400">delay</font><font color="#000000">(</font><font color="#000000">readTime</font><font color="#000000">)</font><font color="#000000">;</font> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<font color="#434f54">// delay in between reads for stability</font>
<font color="#000000">}</font>

</pre>