untitled

Helping Sam receive his commands ................................................

The receiver circuit that Sam uses to make sense of all your transmitted com-

mands is shown in Figure 13-4. Here’s how this one works:

The receiver moduleseparates the coded signal sent by the transmitter

from the 433.9 MHz carrier wave. The output of the receiver module at

Pin 2 is the decoded signal, as shown in Figure 13-2.

VR1is a voltage regulator that takes the 6 volts supplied by the battery

pack and supplies a steady 5 volts because the transmitter module has a

maximum voltage of 5.5 volts. We provided a separate battery pack for

this section of the circuit to provide a stable supply for the radio receiver.

We found this setup gives much more consistent reception than setting up

the receiver to share a battery pack with the rest of the circuit.

S1is the on/off switch for the circuit.

15

2

1 17

(^414)
3
S 4
IC 1
16

• VR1

VOUT

VIN

S 5

6V

6

5

8

7

9

18

10

13

12

S 1

S 2

S 3

3

2

4

1

TRANSMITTER

MODULE

ANTENNA

R1

Figure 13-3:
Sam’s
transmitter
circuit.

Chapter 13: Sensitive Sam Walks the Line 305