A new participatory approach that makes use of and improves local end-users knowledge has been used to design a new portable mechatronic system for humanitarian demining applications in Sri Lanka, using power tillers as core module. They are very simple and versatile machines with large scale diffusion in developing countries, where they are commonly used for agriculture and transportation purposes. The system, composed by a tractor unit, a ground processing tool and a vegetation cutting tool is firstly introduced. The paper then focuses on the portable control unit allowing to control the machine from remote distance, in case unexploded ordnance or other fragmentation weapons are known to be present. The module allows forward motion by acting on the clutch, differential and acceleration of the power tiller; steering is controlled by additional brakes, mounted on the driving axle. Two wheels supporting the ground processing tool on the front of the machine are connected to the rear driving ones through tracks. The module can be fit to every kind of power tiller actuated by levers, using differential gear, after only little adjustments. The control is pneumatic and it is powered by the engine of the power tiller itself. The unit, like the others modules, responds to the requirements of safety, low-cost and simpleffectiveness.