Behaviour of shield

315MHz and 433MHz wireless connections are very commonly used by consumer electronics including weather stations, home automation remote controls, power consumption meters, car alarms, and also many DIY projects.
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wt29
Posts: 1
Joined: Sun Nov 20, 2011 7:30 am

Behaviour of shield

Post by wt29 » Wed Jan 02, 2013 5:58 am

Hi Jon,

I've had a 433Mhz shield for a couple of years and never seemed to have much success with it. Todad I got the device out of the deep freeze and had another go. I have at least 2 433 devices in the house, one is a Scientific Oregon basic weather station the other an Efergy household energy monitor. I had visions of figuring out the Efergy protocol.

To cut the story short when I turn every device I can find off - this includes the 433 devices and most of my computing equipment (especially WiFi et) but I still get a string of pulses from the device. I've cut it down to just the shield, a 5V power supply and a HP 100Mhz CRO and it never changes. I get a consistent rapid collection of 3V pulses from the device. Removing the antenna or touching the antenna connection makes no difference to the pulse trains (probably shouldn't vary the amplitude) but I thought it might change the pulse trains.

Should I be getting any output from the device with no 433Mhz transmitters anywhere in the vicinity? I have a sketch which just counts the pulses and I get appoximately 1500 pulses / second.

Any suggestions?

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