Delons
Posts: 1
Joined: Sun Jan 19, 2014 1:47 pm

Temperature Program

Sun Jan 19, 2014 1:51 pm

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?

DrakkenLemmont
Posts: 2
Joined: Fri Jan 24, 2014 5:48 pm

Re: Temperature Program

Fri Jan 24, 2014 6:37 pm

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

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chrisryall
Posts: 155
Joined: Wed Nov 27, 2013 11:45 am
Location: Wirral UK
Contact: Website

Re: Temperature Program

Fri Jan 24, 2014 8:26 pm

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?

Gadjetnut
Posts: 18
Joined: Fri Apr 05, 2013 9:13 pm

Re: Temperature Program

Sat Jan 25, 2014 12:22 am

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

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Burngate
Posts: 6333
Joined: Thu Sep 29, 2011 4:34 pm
Location: Berkshire UK Tralfamadore
Contact: Website

Re: Temperature Program

Sun Jan 26, 2014 9:57 am

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

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