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.

Nice little portable charger for Ipod/Iphone

I came across this Ipod/Iphone charger the other day in B&Q and after a search on Ebay I found it for £7.99 including postage, BARGAIN!
It retails for £19.99 and comes with two Energiser Lithium AA batteries.

It uses a fold out connector at the rear that forms the holder for the Ipod.

It also acts a a stand for the Ipod/Iphone whilst charging.

On the bottom it has an adjuster than alters the distance between the connector and the back of the charger so it will fit a nano all the way upto the Iphone 3G and Yes it will charge the 3G Iphone.














All in all a very nifty device that will keep you going when you're no where near a mains socket.