∧ FIGURE 12. Photo of how to make
custom wiring ( www.robotis.com).
sensors, you need a way to connect to
them since they are on the bottom of
the foot. We cut out slots for each
force sensor to slide through.
There are many different types of
force sensors you can use. Tekscan
makes FlexiForce sensors which are very
thin piezoresistive force sensors (Figure
14; www.tekscan.com). When using
a resistor to measure force, you usually
need to construct a calibration circuit to
get the greatest sensitivity and range of
load detection. After calibration, you
also need an Analog-to-Digital converter to convert the signal to a digital
signal that the computer can read.
Next Month ...
We showed you the physical
∧ FIGURE 13. Photo of custom wiring.
∧ FIGURE 14. Photo of FlexiForce force
sensor ( www.tekscan.com).
aspects of DARwIn and how you could
make your own. Next month, the
last part of this series will detail some
of the software used to control
DARwIn, as well as a peek of next
year’s design. SV
SERVO 01.2007 43
