Figure 1. RF 4 channels remote Transmitter
This is a very simple Wireless RF transmitter circuit that consists of the Holtek
HT-12E encoder chip and AM
418MHZ-transmitter module (WZ-X01, other similar device can be used). Using
the hybrid RF xmit/receive modules make building
the RF remote control a lot easy.
The wireless transmitter can be powered with any voltage from +3 to +12V. The
total current consumption is less than 5ma. Depending on the supply voltage,
you may need to select a difference resistance value for the oscillator
resistor R1. The recommended oscillator is Foscd (decoder) = 50 Fosce
(encoder). See data sheet
for more
details.
The individual security code of the transmitter is preset by dip-switches
S5, up to 256 combinations.
When any of S1-S4 is pressed the /TE pin is pulled low, and power is
applied to both the encoder chip and wireless transmitter module, the encoder then
starts scanning and transmitting the status of the 12bits address and data
serially.
Figure 2 RF 4 channels receiver circuit
The circuit diagram for the wireless receiver (WZ-R01 or other similar device can
be used) is shown in figure 2. The decoder U1(HT-12D)
receives serial addresses and data from the encoder that are transmitted by
the RF wireless transmitter module. It compares the serial input data three times
continuously with its local addresses. If no error or unmatched codes are
found, the input data codes are then decoded and transferred to the output
pins D8~D11. The VT pin also goes high to indicate a valid transmission,
which will turn on the LED1. The addresses of the decoder (set by S1) have
to be matched with the transmitter encoder. The outputs of U1 drive the four
TIP30 PNP transistors that can be connected to the relays or lamps.
The operating range of this wireless transmitter/receiver is dependent on the
choice and position of the antenna. The space around the antenna is as
important as the antenna itself. Try to keep the antenna away from other
metal in the system such as batteries and PCB ground plane. The following
types of antenna are recommended.
Antenna Configuration
the
transmitter kit for only $20
Kit includes(no pcb):
1 Ming RF Transmitter module,
WZ-X01, or WZ_T434
1 Holtek HT-12E Encoder IC
8 1N4148 Diodes
4 Push button Switches
1 Dip switch
1 Resistor (680K)
the
Receiver kit for only $24
Kit includes (no pcb):
1 Ming RF Receiver module,
WZ-R01, or WZ-R434
1 Holtek HT-12D Decoder IC
4 1N4001 Diodes
4 TIP30 PNP transistors
1 2N3904 NPN transistor
1 Dip switch
3 Resistors (30K, 330,
and 1K)
For additional information and resources check the
![[Under Construction]](images/undercon.gif)
