External Wireless Temperature measurement

This project was required so that I could monitor the temperature inside a temporary lean-to / greenhouse I made to winter some frost hating plants in.

There are basically two modules, the transmitter and the receiver.

Receiver

Transmitter

The transmitter uses a Jeenode from Jeelabs to read the temperature from two DS18B20s, one inside the greenhouse and the other in the form of a probe placed outside the greenhouse to measure the ambient temp.

The receiver uses one of my own PCBs which is essentially a jeenode with an added uSD card slot, the display is from Jeelabs and is designed to sit directly on top of a Jeenode but it's not the cheapest display you can use.  The receiver can also be made using a standard Jeenode instead of my PCB.

I run the transmitter off some old lithium rechargeable 1850 cells taken from an old laptop battery, the receiver also runs on a lithium battery from a mobile phone but you can use any batteries you like from 3 to 5 V.

The battery voltages of both the transmitter and receiver are monitored and displayed on the LCD, the code for the battery monitoring was taken from the Jeelabs blog here and the sleep functions were also from the same post using the Jeelib libraries.

Sketches can be downloaded for transmitter and receiver.

Any questions or comments, feel free.

JeeLabs JeeNode

Whilst looking around the net for information on the Arduino project I come across a few variants on the theme, this one struck me as particularly useful.

This site is run by a guy called Jean-Claude Wippler, he has created his own version of the Arduino called the JeeNode.

JeeNode V5

This derivative of the Arduino is a much slimmer device, intended to form part of an environment monitoring network around a house, the main thig about this design is that it includes a built in wireless transciever which allows these things to talk to each other without having to buy an Xbee board for your Arduino. (You can get two of these for not much more than one Xbee)

It uses the same programming IDE as the Arduino.

The pinout interface for the JeeNode is quite different to that of the Arduino, he has setup 4 ports that can be connected to various sensors like temp, humidity and many more using I2C.  To make programming easy he has also built a ports library.

The wireless interface is also made easy to use with a custom library, this enables you to send and recieve serial data without worrying about any data protocols at either end.  Each device comes pre-programmed with the libraies needed and can talk to each other out of the box, all you need to do is follow the tutorials on the site.

The other thing that interests me, when combined with the wireles capability, is the nice graphical LCD screen.

Graphical LCD

 The Screen comes with a PCB that plugs onto the JeeNode and along with a single AA battery holder/stepup invertor you would get a complete wireless screen showing information from the main unit and even sending data back.

Complete Wirelss screen

The one thiong you'd need to get though is a FTDI programming lead because, unlike the Arduino, it doesn't have the USB programming interface. I found mine here.

I found all this at Jeelabs, based in the Netherlands.