Design time

Thanks to his Year 12 Design and Technology course at The Armidale School, Henry Mitchell has designed and built an autonomous, paddock-based sheep weighing station that has huge market potential.

Story Ken Eastwood   Photo courtesy The Armidale School

A couple of years ago, schoolboy Henry Mitchell helped his dad Bill design and build a stand-alone cattle weighing station to help their grass-fed cattle operation. The unit could be towed out to a paddock and, with the enticement of a salt lick or some molasses, cattle would place their two front legs on the scales. An algorithm accurately worked out their full weight and, after reading the animal’s ear tag, would send the information, at any time of day or night, to a database. 

The device not only helped them keep tabs on individual cattle and maximise weight gains in their own business, but quickly became a desired new piece of agtech called Optiweigh. More than 150 units have now been sold in Australia, at $16,000 a pop.

So, in 2021, when Henry needed a project for his Year 12 Design and Technology course at The Armidale School (TAS), he decided to see if he could develop a similar product for sheep. “We had a chat about the idea and he just ran with it,” Bill says. “With Optiweigh I’ve been involved in some incubation programs and courses for start-up businesses and, as a schoolkid, the work he’s done would stack up against any of them. I’m very proud of what he’s done.”

Henry initially worked with 23 sheep from one of the Optiweigh business partners, in order to design an algorithm that could accurately ascertain a sheep’s mass when just the front legs are on the scales. And the algorithm appeared to work well. “It seemed to be really consistent and had a correlation of .9995, which was astounding,” Henry says. However, in further trials on a big mob of Merinos at Walcha he discovered that the amount of fleece growing over the head could affect the algorithm, as did wet wool, so Henry had to keep developing the software.

In terms of the hardware, he says TAS’s excellent trade training centre had everything he needed for welding, cutting, bending metal and assembling. “The teachers there are really terrific, with lots of good insight,” he says.