[[!meta title="Playing With Sensors"]]

(Notes from a little Workshop during HAR 2009)


* <b>GPIO</b>: LEDs, Switches, Multi-position keylocks,
receiving the german DCF77 time signal station (maybe),
using GPIO pins to build a 1-Wire bus
* <b>1-Wire bus</b>: Digital thermometers

# Hardware Notes

## Soekris net4801 GPIO pins wrong in manual

The GPIO Pins in the Soekris net4801 manual are utterly wrong
(at least there is a manual, unlike for the net5501, although
one with many errors...).

<table border="1">
<tr>
<td>JP5 Pin</td><td>PC87366 Pin</td><td>JP5 Pin</td><td>PC87366 Pin</td><td>JP5 Pin</td><td>PC87366 Pin</td><td>JP5 Pin</td><td>C87366 Pin</td></tr>
<tr><td>3</td><td>GPIO16</td><td>4</td><td>GPIO17</td><td>5</td><td>GPIO18</td><td>6</td><td>GPIO19</td></tr>
<tr><td>7</td><td>GPIO20</td><td>8</td><td>GPIO21</td><td>9</td><td>GPIO22</td><td>10</td><td>GPIO23</td></tr>
</table>

## Connecting a LCD module to the 4801 JP5

This example assumes a DIP162 module.

<pre>
LCD	4801		Function			PC87366 Pin

1	11		GND
2	2		VCC
3	nc		VEE (Kontrast)
4	12		RS, GPIO8			GPIO4
5	13		RW, GPIO9			GPIO5
6	15		Enable, GPIO10			GPIO13
7	3		D0 Display Data LSB, GPIO0	GPIO16
8	4		D1, GPIO1			GPIO17
9	5		D2, GPIO2			GPIO18
10	6		D3, GPIO3			GPIO19
11	7		D4, GPIO4			GPIO20
12	8		D5, GPIO5			GPIO21
13	9		D6, GPIO6			GPIO22
14	10		D7, GPIO7			GPIO23
15	nc
16	nc
17	nc		LED+
18	nc		LED-
</pre>

## Connecting a DS18B20 to Soekris 5501 JP5

<pre>
                          __________
                         |          |
                         | DS18B20  |
       Vin               -----------
          |              1|  2|   3|
          |               |   |    |
          _               o---|----|
         | |              |   |
      4k7|_|            GND   |
          |                   |
          |                   |
uC -------o--------------------


2      = DQ   ----->   Pin X / GPIO x
1      = GND  ----->   Pin 20
3      = Vdd           GND when using parasite power
Vin    = 5V   ----->   Pin 2
</pre>

# External References

## In english

* [1-Wire Communication Through Software](http://www.maxim-ic.com/appnotes.cfm/appnote_number/126)
* [1-Wire File System](http://owfs.org/)
* [1-Wire Bus Wikipedia Entry](http://en.wikipedia.org/wiki/1-Wire)

## In german

* [1-Wire Bus System](http://www.ip-symcon.de/wiki/index.php/1Wire-Bus-System)
* [1-Wire Bus Wikipedia Entry](http://de.wikipedia.org/wiki/1-Wire)