FIGURE 8. A wireless version of VEX control
glove with three flexible resistors, two
potentiometers, and five pushbutton switches
connected to the VEX RC receiver.
time. I do plan to obtain its position indoors by using a
combination of ultrasonic PING))) sensors or Polaroid 6500
sonar rangers with Time of Flight (TOF) and trilateration or
triangulation techniques to calculate the glove’s position in
3D. Another alternative would be to implement a low cost
gyro and accelerometer combination board (IMU) used for
RC helicopters to keep track of the glove’s position and
orientation.
Finger Positions
The control glove’s fingers allow you to move distant
objects by just bending your index finger with natural
motions. The finger positions are read using the
microcontroller’s 10-bit ADC to digitize the voltages that are
generated by bending
the flexible resistors;
this changes the
resistance depending
upon how much each
resistor is bent. In
order to obtain the
best readings
possible, each finger
is individually
calibrated by having
the operator move it
from its minimum
position to its
maximum position,
then the voltages are
recorded so that they
can be used to
calibrate the finger
position data. The
finger positions are
mapped by the
remote application
FIGURE 9. A wireless glove is the
perfect companion to controlling VEX
robots such as the Telepod tripod
(photographer's assistant).
52 SERVO 11.2011
using the calibration data so that each finger position can
move the individual servo or motor (or multiple servos or
motors).
Pushbuttons
Five small pushbuttons (shown in Figure 8) provide
functionality similar to a PC joystick trigger and fire buttons,
but also allow the wearer to select which motors to move
or which lights to turn on/off. The pushbuttons can be read
and de-bounced using the Easy C Pro digital input function
firmware for the IO11-IO16 digital input pins. Pushbutton
switches are of the miniature PCB variety. Each is hot glued
to each forefinger or knuckle so that it is easily accessible
from the user’s other hand. Each pushbutton switch on the
glove is wired to the digital inputs I011 through IO16 of the
microcontroller using wire-wrap wire.
The pushbutton switches can be assigned to perform a
task on the microcontroller as shown in Table 2.
How It Works
The system consists of the microcontroller and glove to
digitize the finger positions (flexible resistors) and the
glove’s orientation. It works by having the Easy C Pro
firmware simply digitize the glove’s finger positions by
reading the voltages across the flexible resistors whose
resistance varies with the angle that each finger is bent or
flexed. The wearer’s own finger movements are digitized
BUTTON
1
2
3
4
5
TABLE 2. Pushbutton switches.
ANALOG/DIGITAL PIN FUNCTION
IO11 CALIBRATE
IO12 RUN
IO13 RECORD
IO14 PLAY
IO15 FIRE