Multiplexing is fun on Raspberry Pi

<ol><li><div align="center" class="none" lang="en-US"><font face="Century Schoolbook L, serif"><font style="font-size: 12pt">I2C &ndash; the extension of GPIOs</font></font></div></li><li><h2 align="justify" class="western" lang="en-US" style="font-weight: normal; page-break-after: avoid;"><font face="Century Schoolbook L, serif"><font style="font-size: 12pt">The Raspberry Pi has 26 ports out of w