Electronics_Projects_For_Dummies
.pdf
260 Part III: Let There Be Light
17.Attach the cover to the box with the included screws.
The completed box is shown in Figure 11-22.
Figure 11-22:
The transmitter all put together.
Making the receiver circuit board
The receiver, quite logically, receives the signal sent by the transmitter. You will eventually affix the receiver circuit to the body of the go-kart, but don’t put the kart before the horse (so to speak): Before you affix the receiver, you have to build it.
To build the receiver circuit, follow these steps:
1.Insert the ICs on the breadboard, as shown in Figure 11-23.
Be sure to leave room between each IC to place wires (as shown in the final figure in this section, the upcoming Figure 11-32). Also, leave room at the end of the board near the decoder to insert the IR detector and the resonator. Finally, leave room at the end of the board near the H- bridge to add terminal blocks.
Chapter 11: Controlling a Go-Kart, Infrared Style 261
H-bridge IC3 Inverter IC2 Decoder IC1
Figure 11-23:
Insert the ICs on the breadboard.
2.Insert the voltage regulator, resonator, and IR detector on the breadboard, as shown in Figure 11-24.
Voltage regulator |
Resonator |
IR detector |
Figure 11-24:
Insert the discrete components.
262 Part III: Let There Be Light
Figure 11-25 shows how the circuit uses each pin of the voltage regulator and IR detector (referred to as discrete components).
Input |
+5 volt |
|
|
|
voltage |
output |
Output |
+V |
+V |
Figure 11-25:
Pinouts for the discrete components.
Ground |
Ground |
Ground |
3.Insert four terminal blocks a few rows in from the end of the breadboard, as shown in Figure 11-26.
Chapter 11: Controlling a Go-Kart, Infrared Style 263
Figure 11-26:
Insert terminal blocks on the
breadboard.
4.Insert wires to connect each component to the + voltage bus and a wire to connect the two + voltage buses, as shown in Figure 11-27.
Note that you connect the +5 volt output of the voltage regulator to the + voltage bus because the voltage regulator takes the approximately +6 volts from the battery and changes it to +5 volts. It then supplies those +5 volts to the + voltage bus so that it can be used by the other components.
Figure 11-27:
Connect components to the +V bus.
264 Part III: Let There Be Light
5.Insert a set of one 10 microfarad and one 0.1 microfarad capacitor between the + voltage bus and the ground bus next to the V+ input for the decoder IC. Do the same for the inverter IC and the H-bridge IC, as shown in Figure 11-28.
These capacitors filter out electrical noise introduced to the + voltage supply for each IC by the DC motors.
0.1microfarad capacitors
Figure 11-28:
Insert capacitors on the breadboard.
10 microfarad capacitors
6.Insert wires to connect each component and terminal to the ground bus (marked with a – on this breadboard) and insert a wire to connect
the two ground buses, as shown in Figure 11-29.
The resonator in the center of the three leads is the ground lead.
Chapter 11: Controlling a Go-Kart, Infrared Style 265
Wire connecting |
Voltage regulator |
Decoder |
|||||
2 ground buses |
to ground bus |
to ground bus |
|||||
|
Terminal block |
H-bridge |
|
IR detector |
|||
|
to ground bus |
to ground bus |
|
to ground bus |
|||
|
|
|
|
|
|
|
|
Figure 11-29:
Connect components to the ground bus.
Terminal block |
H-bridge |
Resonator to ground bus |
to ground bus |
to ground bus |
|
7.Insert wires to connect the decoder IC, resonator, and IR detector, as shown in Figure 11-30.
266 Part III: Let There Be Light
Pin 4 of the decoder
to output pin of the
IR detector
Figure 11-30:
Insert wires between pins on the decoder, resonator, and IR detector.
Pin 2 of the decoder |
Pin 3 of the decoder |
to the outer pin |
to the other outer pin |
of the resonator |
of the resonator |
8.Insert wires to connect the decoder, inverter, and H-bridge, as shown in Figure 11-31.
Chapter 11: Controlling a Go-Kart, Infrared Style 267
Pin 12 of the |
Pin 13 of the |
Pin 7 of the |
Pin 5 of the |
inverter |
inverter |
decoder |
decoder |
to Pin 15 |
to Pin 10 |
to Pin 9 |
to Pin 13 |
of the H-bridge |
of the H-bridge |
of the H-bridge |
of the inverter |
Figure 11-31:
Inserting wires between pins on the decoder, inverter, and H-bridge.
Pin 9 of the |
Pin 1 of the |
Pin 2 of the |
Pin 6 of the |
H-bridge |
inverter |
inverter |
decoder |
to Pin 1 |
to Pin 2 |
to Pin 7 |
to Pin 1 |
of the H-bridge |
of the H-bridge |
of the H-bridge |
of the inverter |
9.Insert wires to connect the terminal blocks to the H-bridge and voltage regulator, as shown in Figure 11-32.
268 Part III: Let There Be Light
Input pin |
Pin 14 |
Pin 11 |
of voltage regulator |
of H-bridge |
of H-bridge |
to +V pin |
to other pin |
to terminal |
of battery |
of terminal block |
block |
terminal block |
for motor R |
for motor R |
Figure 11-32:
Wiring the
terminal
blocks.
Pin 3 |
Pin 6 |
Pin 8 |
of H-bridge |
of H-bridge |
of H-bridge |
to terminal |
to other pin |
to +V pin |
block |
of terminal block |
of motor battery |
for motor L |
for motor L |
terminal block |
Building the go-kart
If you’ve followed this chapter to this point, all the little wires and doohickeys in the transmitter and receiver circuit are in place to make your go-kart go. However, one thing is missing: the kart itself. This consists of a platform on which you affix
The receiver
The motors
A switch to turn the power on and off
Something to cover the chassis
Chapter 11: Controlling a Go-Kart, Infrared Style 269
Although the covering is optional, it makes the kart look cooler. More importantly, a covering prevents your kids or pets from poking a finger or paw where they shouldn’t and pulling wires loose.
To build the kart itself, follow these steps:
1.Place the breadboard, battery packs, caster, and power switch on the 1⁄2" PVC or plywood sheet, as shown in Figure 11-33.
This will help you to determine how large to make the base of the kart.
We chose a 1⁄2" PVC sheet, 61⁄2" wide and 9" long, which can hold all the components and still leave enough room to rest the top of the kart on the base. You can use a pencil to mark where to cut the 1⁄2" PVC sheet.
Figure 11-33:
Determine the shape of the kart base.
2.Mark a location between the breadboard and the bumper switch where you will drill a hole to feed the wires to the motors.
3.Use the base of the castor as a template to mark the four holes you will drill to mount it to the body.
Figure 11-34 shows the marked PVC sheet.