On Monday, December 1, 2014 10:44:18 AM UTC-6, mikegr...@gmail.com wrote: > > Hi guys, > > I've just started out with the BBB, and am basically wanting to use it > initially, to gather data on temperature and humidity both inside and > outside my property (sensor in each room + 1 outside). Obviously there are > going to be quite a few sensors, is it possible to get all these up and > running at the same time? I know there are lots of GPIO connectors on the > BBB, but only a few voltage connectors, how do I go about splitting these? > > Also, would it be possible to wire up the sensors using alarm cable? They > will be quite far from the controller in some instances. > One thing to worry about is lightning! I have such a system built with VERY OLD technology, which is probably much more resistant to damage, but have had parts of it blown out at times by thunderstorms. i have one sensor just outside the wall of the house for outside temperature. I use the Analog Devices AD590 series, which is a current proportional sensor. The current through the sensor is 1 uA per degree K. Alarm wire is fine, especially with a current sensor, as noise will largely be cancelled out. But, you need a signal conditioner to bias the detector and convert current to voltage. A simple op-amp circuit can do this. I use a pretty fancy humidity sensor that needs signal conditioning by an exotic AD part, but it gives very good results. Calibrating a humidity sensor is a lot harder than a temperature sensor.
Jon -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
