What happens when you have to boil a design down to its bare bones to fit an African budget?

The answer – it transpires – is that you need two backyard gardeners whose day jobs have them among the top echelons of Australian science and engineering.

The first of these gardeners is one of CSIRO’s most experienced irrigation scientists – Dr Richard Stirzaker - himself born in Africa. Richard set about developing an inexpensive soil moisture tension sensor that could repeatedly detect two critical soil moisture switch points in a drying soil. The sensor was modelled on the venerable 70-year old gypsum block.

African farmers enjoying a Chameleon
African farmers enjoying a Chameleon


The second of these gardeners is MEA’s own engineering director – Dr Andrew Skinner - born in South Australia and descended from a long line of Irish peasant farmers. Andrew’s job was to develop the four-depth display technology to show moisture levels as colours: blue for ‘moist’, green for ‘growing’ and red for ‘drying’.

That MEA was able to build a robust solar-powered colourful ‘Chameleon’ display unit to match CSIRO’s sensor owed much to our considerable investment in the Plexus product for the more sophisticated Australian soil moisture market. We had already amortised the cost of the enclosure tooling and the development of solar charging systems; these basic components transmogrified into the Chameleon housing and power systems.

Richard’s idea is that foisting such tools onto farmers as a ‘solution’ to their irrigation issues is a waste of time. Instead, the Chameleon is designed to allow African farmers to ‘learn’ what is going on in their soils and crops. Simple the technology may be, but the lessons that can be drawn from it are surprisingly practical and down-to-earth.

With special thanks to Erika Kawashima, who built the first ‘Irroborti’ prototype the hard way (on Veroboard).


Erika Kawshima at the electronics bench

Erika Kawashima at the electronics bench.


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