Temperature Monitoring

Temperature data from around the space is to be log via Cacti.
Sampling done with DS18S20 1-wire digital thermometer, these can be daisy chained of the other arduino and MQTT devices.
Aim to publish a standard format MQTT message that a script on Holly will decode and push to cacti

Posible Arduino to hook into

• Gatekeeper in members box room (arduino, ethernet)
• LED Matrix in studio (arduino mega, ethernet)
• Vending Machine in workshop (nanode)
• Energy Monitor in blue room cupboard (XRF)

Cheap and cheerful thermistor workshop

I have a bag of surplus 47k thermistors (about 500) and I intend to build a number of circuits to measure temperature starting with the very simplest and culminating in a teachable HackSpace project with reasonable accuracy. We will put these devices in fridges, near heat sources, near doors, windows, indoors, outdoors, you name it.

The component:

• Listed in stores as "Future Electronics B4090K Thermistor 47k 5%"
• I think it may be this one
  • http://uk.futureelectronics.com/en/Search.aspx?dsNav=Ny:True,Ro:0,Nea:True,N:477-4294920237
  • http://uk.futureelectronics.com/en/Technologies/Product.aspx?ProductID=NTCLE100E3473JB0VISHAY8666240
• however, the Vishay product may be obsolete and the tolerance is listed as 1.5% rather than 5%

  VISHAY 
   NTCLE100 Series NTC 47 kOhm ±1.5 % Radial Leaded Standard Precision Thermistor
   Mfr Part#:  NTCLE100E3473JB0
   Packaging : BAG 
   Std Packaging Qty: 500
   Min Order Qty: 1
   As low as:  £0.1751  (GBP)
   In Stock:  No
   Type: 
   NTC
   Resistance: 
   47 kO
   Tolerance (%): 
   ±1.5 %
   B-constant: 
   4090 °K
   Temperature Range: 
   -40 to +125 °C

Some Google digging reveals...

• http://www.vishay.com/docs/29049/ntcle100.pdf
• these thermistors are colour coded
  • Yellow Violet Orange Gold
    • B25/85-VALUE = 4090K (+/- 5%) (the gold means 5%)

The simplest circuits and Arduino code...

• http://arduino.cc/playground/Main/InterfacingWithHardware#envtture
  • http://arduino.cc/playground/ComponentLib/Thermistor
  • http://arduino.cc/playground/ComponentLib/Thermistor2
  • http://arduino.cc/playground/ComponentLib/Thermistor3

Michael Erskine 06:43, 14 December 2011 (EST)

Old Notes

• Temp sensors dotted around space
• Nanode again
• Small wireless units or daisy chain of dalas one wires?
• Humidity sensor's?
• Push to cacti
• Query from irc