Page 174 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

Output
Input
Q8 Q7
Q6
Q5
Q4
D C B A Q9 Table 7.2 4028 Truth Table Q3 Q2 Q1 Q0
0 0 0 0 0 0 0 0 0 0 0 0 0 1
0 0 0 1 0 0 0 0 0 0 0 0 1 0
0 0 1 0 0 0 0 0 0 0 0 1 0 0
0 0 1 1 0 0 0 0 0 0 1 0 0 0
0 1 0 0 0 0 0 0 0 1 0 0 0 0
0 1 0 1 0 0 0 0 1 0 0 0 0 0
0 1 1 0 0 0 0 1 0 0 0 0 0 0
0 1 1 1 0 0 1 0 0 0 0 0 0 0
1 0 0 0 0 1 0 0 0 0 0 0 0 0
1 0 0 1 1 0 0 0 0 0 0 0 0 0

Each function is controlled by an electric motor or motor/solenoid
combination that can be powered by an NPN transistor. So each
function requires one NPN transistor. Four transistors connected to
the outputs of the 4028, labeled Q1 to Q4, control this electric car.
For purposes of a clear illustration, Fig. 7.6 shows only one NPN
transistor connected to output Q1 powering an electric motor. The 153
exact model R/C car I used when writing this chapter is no longer
available. Even so, most inexpensive R/C cars will function in a
similar manner. Remove the R/C equipment from the car. You will
be left with wires leading to the drive motor that will either have to
be grounded or connected to Vcc to power the motor. Turning left
and right is usually accomplished with an inexpensive solenoid.
Again check the wires from the steering solenoids to see if they
need to be connected to ground or connected to Vcc.

Walkie-talkies
Radio Shack sells a number of inexpensive walkie-talkies. Since
the operating distance of the microphone on the SRC is about 1 ft,
using a pair of walkie-talkies increases the distance with which
one can operate the mobile robotic platform via the SRC. The
speaker output of the walkie-talkie is connected to pin 46 on the
HM2007 through capacitor C1. Capacitor C1 will block any DC
component output from the walkie-talkie.

Acoustic coupling
If you don’t want to take apart and solder wires between the
walkie-talkie and SRC directly, you can try an acoustic coupling.
Team LRN Speech-controlled mobile robot