First Sensor: The Story So Far

The first prototype sensor is out in Oxford, near the Castle Mill Stream in a small parallel stream called Wareham Stream. 

On Saturday the distance to the water level was 66cm, now it’s 64cm, so I hope this is a rise in the water level and not a sag of my fixings!

The radio reception has been a bit of a problem. According to 289-adding-antennas-to-ciseco-radios the wire whip antenna is 1 quarter of the wavelength at 82.2mm. (868MHz)  However, it’s buckled over inside the case whereas it should be vertical, perpendicular to the girder the sensor is stuck to.  This can be resolved, but needs a hole drilled in the box to allow the wire to emerge. If I’m doing that I might get a better result with a half wavelength antenna at 16cm. At night the reception gets worse, which could be down to a baby monitor being turned on. 

Andrew, another contributor to the project, is building an RSSI (Receive Signal Strength Indicator) test box, which allows us to wander around checking reception, rather than waiting 5 minutes for the next reading (or not, if it’s out of range).

More to come on this later.

Making a flood detection network in Oxford, using low cost sensors and volunteers

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