1 Basic description of the design
The minesweeper extension will enable the ASURO robot to detect metallic objects underneath the
halved Ping-pong ball-glider. This will allow you – of course within the scope of the robot's and the
kit's possibilities - to develop the scenario of a robotic mine detector respectively treasury hunter or
a simplified version of a detector and tracer for cables, reinforcing bars and I-beams.
To avoid abundant explanations for the physical theories for magnetic fields and complex AC-
currents, the following chapters strictly document the basic description of the design and the user's
manual.
An operational amplifier (Opamp) has been applied to stimulate oscillations in the resonant circuit
consisting of a capacitor (C) and an inductor (L) applying an open pot core. Application of the
magnetically open pot core allows the magnetic field to expand into the surrounding free field and
to be influenced by neighbouring metallic objects.
Fig. 1 displays the schematic diagram. The resonant circuit consists of inductance L1 and capacitor
C1. The design allows resonant behaviour by cyclically exchanging the capacitor's electric field
energy and the inductor's magnetic field energy. The design's transfer frequency depends on the
values for the capacitor and for the inductor. Assuming negligible losses, the resonator's frequency
may be calculated by the following formula:
f
0
=
1
2
L C
Exchanging the capacitor's electric field energy and the inductor's magnetic field energy cannot be
performed without losses and the losses will cause the oscillation to decay within a few cycles. We
continually have to feed energy into the system to compensate losses. In analogy to a children's
swing, the system will have to apply the correct phase in feeding the energy into the circuit.
Figure 1: Schematics for the "Minesweeper"-Extension
