Step 7: Lower power module and neighbourly relations
To keep neighbourly relations happy, especially with digital TV, send the data as far as it needs to go but no further. One can argue about the legali...
Have a water tank you want to measure or a dam or a gate? Want to detect a car coming down the drive but don't want to string wires through the garden? This instructable shows how to send data 500 metres with 100% reliability using picaxe microcontroller chips and 315Mhz or 433Mhz radio modules.
The transmitter prototype was built on a piece of prototype board. There are a myriad of low power 10mW RF modules available which work well up to a range of about 30 metres. However, once the power goes up above half a watt the RF tends to get back into the picaxe chip and cause resets and other strange behaviour. The answer is to remove the module's antenna and take the RF away with 3 metres or more of 50ohm coax and build a proper dipole antenna. This also boosts the range considerably.
Bio:Dr James Moxham is a general medical practitioner in Adelaide, Australia. His interests include general family medicine, medical politics, microcontrollers and tending a rose garden. He lives on a pro...read more »