Alister Henson’s phone-controlled slurry pump

On the dairy and arable farm near Glastonbury, Somerset, where he works, Alister Henson devised a great way to control the tractor-powered slurry pump that was being used away from the main farm buildings.

Instead of buying in an off-theshelf radio remote control system, which would have cost several hundred pounds and had limited
range, he built his own version that uses the mobile phone network to  give unlimited reception range.

Using a relatively cheap microprocessor, he rigged up a system that takes a mobile phone as the receiver and then uses incoming
tone signals to operate relays connected to circuits that operate the tractor’s pto and engine rev preset switches.

Now he can switch the tractor pto on and off, and set the tractor revs to one of two presets, all by ringing the tractor and keying in a one-digit code.