WEB Thermometer
SECTION 1
Objective

 

 

 

SECTION 2
The circuit diagram

SECTION 3
PCB information

 

 

 

SECTION 4
Assembly information

Properties:   Range     -40° to 135° C

                     Accuracy     0,7° C  (-30° to 100° C )

Max cable length: 15m

 Cold outside? Warm? This little simple thermometer can be used to monitor and log the temperature anywhere in a radius of 20 meters from your computer. A simple program downloadable can be used to display the temperature on our desktop. The program also log the temperature  to a local file, can update a webpage once every minute, and creates a new log-file every 24 hours. Additional programs can  be used to extract data to graphic printouts of hour, day or week temperature statistics or to a WEB-server. 

Now, here is the circuit diagram of the simple thermometer. It is simple, uses few components. Power supply is not needed as the needed power is supplied by the computerīs Com-port.

The PCB I use is given here as a gif file, if you don't want to use the CAD database. Be shure the size is 10mm by 50mm

termlays.gif (2656 bytes)

First, solder the 78L05 regulator(U2) into their holes from the component side on the PCB. This is the placement:

termpl_c.gif (2620 bytes)

Then, from the solder side of the PCB mount the rest of the components; diodes, capacitor and resistors. Here is the placement for this:

termpl_s.gif (2759 bytes)

Here are some pictures of the parts:


Solder side with mounted components.


Component side with mounted components.

term03.JPG (29369 bytes)
Connector mount.

Back       Tillbaka


Graphic display of temperatures
This example is from an 8-channel thermometer


Collect components
PCB board, components, cable, connector....


The completed unit
Sensor, electronics (white swelling on cable) and the connector to the COM-port

sensor.jpg (3140 bytes)

The sensor

Sensor is soldered to a 3 lead cable, and covered with a shrink-tube(shrinks when heated), filled with silicon moisture. Electronic components are also covered.

adaptor.jpg (2801 bytes)
PCB is enclosed in a white or black shrink-tube.