https://www.heepy.net/index.php?title=Sensirion_humidity_%26_temperature_sensors&feed=atom&action=historySensirion humidity & temperature sensors - Revision history2024-03-29T01:26:50ZRevision history for this page on the wikiMediaWiki 1.35.2https://www.heepy.net/index.php?title=Sensirion_humidity_%26_temperature_sensors&diff=1257&oldid=prevMorris at 08:56, 17 January 20122012-01-17T08:56:40Z<p></p>
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<tr><td class='diff-marker'>−</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The manufacturer's data sheet is at </div></td><td class='diff-marker'>+</td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The manufacturer's data sheet is <ins class="diffchange diffchange-inline">duplicated </ins>at </div></td></tr>
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</table>Morrishttps://www.heepy.net/index.php?title=Sensirion_humidity_%26_temperature_sensors&diff=1256&oldid=prevMorris: Created page with "Library and demo program for SHT15 temperature and humidity sensor from Sensirion. Get one on a breakout board from sparkfun.com. It's not cheap, but it seems to produce repeatab…"2012-01-17T08:56:00Z<p>Created page with "Library and demo program for SHT15 temperature and humidity sensor from Sensirion. Get one on a breakout board from sparkfun.com. It's not cheap, but it seems to produce repeatab…"</p>
<p><b>New page</b></p><div>Library and demo program for SHT15 temperature and humidity sensor<br />
from Sensirion. Get one on a breakout board from sparkfun.com. It's<br />
not cheap, but it seems to produce repeatable and stable output. <br />
<br />
This driver doesn't depend on any hardware support except GPIOs,<br />
so it should run on any AVR. You might need to provide different<br />
uart routines to get serial output from the demo program on say an <br />
atmega8. Even with the float stuff it still fits in 8k. <br />
<br />
The manufacturer's data sheet is at <br />
http://www.sparkfun.com/datasheets/Sensors/SHT1x_datasheet.pdf<br />
<br />
It speaks a two wire protocol that's almost like i2c but just slightly<br />
gratuitously different, so you have to bitbang it. Its data line is open drain,<br />
so in theory it might be able to coexist with an actual i2c<br />
bus on the same wires, but when i tried it it seemed to hang <br />
the bus in its default power-on state. <br />
<br />
It has two resolution modes, 12 bit humidity + 14 bit temperature,<br />
and 8 bit humidity + 12 bit temperature, of which I've only<br />
implemented the higher resolution one. To use the other, you<br />
write 0x01 to the status register and then use a different <br />
polynomial (detailed in the datasheet) to convert the readout<br />
to real floating point values. If you want more accuracy, read<br />
temperature first, and then pass the temperature reading to <br />
sht_humidity_comp() which adds temperature compensation to the<br />
basic humidity reading. <br />
<br />
It also has a low-voltage warning bit and a builtin electric<br />
heater which you can apparently use to test it - turning it on<br />
draws a few mA and causes the temp reading to go up and the <br />
humidity reading to go down, as expected. Don't leave it on permanently. <br />
<br />
eric volpe http://heepy.net 4/21/2010</div>Morris