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Temperature Program

Posted: Sun Jan 19, 2014 1:51 pm
by Delons
I have an outdoor wood boiler and I want to have a temperature sensor that transmits to a web page. The temp goes up to 200f. What do I need? How do I go about doing this?

Re: Temperature Program

Posted: Fri Jan 24, 2014 6:37 pm
by DrakkenLemmont
I'd suggest this. It monitors the temp, and shows it on a nice web interface along with a 24 hour history graph.

http://www.projects.privateeyepi.com/ho ... ng-ds18b20

Re: Temperature Program

Posted: Fri Jan 24, 2014 8:26 pm
by chrisryall
Eyeballed this and was puzzled by its having a 4k7 Ohm resistor across every (both in the diagram) 2-3 sensor legs.

These same wires are connected together to 3V5,and ground respectively at the GPIO end, and in the example should (if my O-level physics serves me right) simply offer a 2k35 resistance, reducing inversely as you add more sensor/resistor pairs.

Am I being stupid? if so why?

Re: Temperature Program

Posted: Sat Jan 25, 2014 12:22 am
by Gadjetnut
It's a pull up resistor. Refer the datasheet link at the bottom of this page:

http://www.privateeyepi.com/store/index ... duct_id=63

Re: Temperature Program

Posted: Sun Jan 26, 2014 9:57 am
by Burngate
chrisryall wrote:These same wires are connected together to 3V5,and ground respectively at the GPIO end
No they're not! Pin 1 goes to ground, Pin 2 is on the GPIO