TWS-434 and RWS-434 are extremely small, and are excellent for applications
requiring short-range RF remote controls. The transmitter module is only
1/3 the size of a standard postage stamp, and can easily be placed inside a
small plastic enclosure.
The transmitter output is up to 8mW at 433.92MHz with a range of approximately
400 foot (open area) outdoors. Indoors, the range is approximately 200
foot, and will go through most walls.....
The TWS-434 transmitter accepts digital inputs, can operate from 1.5 to 12 Volts-DC, and makes
building a miniature hand-held RF transmitter very easy. The TWS-434 is
approximately the size of a standard postage stamp.
TWS-434 Pin Diagram
Sample Transmitter Application Circuit
The receiver also operates at 433.92MHz, and has a sensitivity of 3uV. The
RWS-434 receiver operates from 4.5 to 5.5 volts-DC, and has both linear and
Click on picture for larger image
RWS-434 Pin Diagram
maximum range, the recommended antenna should be approximately 35cm long.
To convert from centimeters to inches -- multiply by 0.3937. For 35cm, the
length in inches will be approximately 35cm x 0.3937 = 13.7795 inches
long. We tested these modules using a 14", solid, 24 gauge hobby type
wire, and reached a range of over 400 foot. Your results may vary depending on your surroundings.
Sample Receiver Application Circuit
example above shows the receiver section using the HT-12D decoder IC for a 4-bit RF
remote control system. The transmitter and receiver can
also use the Holtek 8-bit HT-640/HT-648L remote control encoder/decoder
combination for an 8-bit RF remote control system. Here are the schematics
for an 8-bit RF remote control system:
to download the RWS & TWS datasheet in Adobe PDF format.
Using the outputs of the HT-12D or
HT-648L decoder ICs to drive relays is quite simple. Here are schematics
showing how to drive relays directly from the data-output pins of the decoder.
NPN Relay Driver Circuit
PNP Relay Driver Circuit
Another option for driving
relays would be to use a high-voltage, high-current, Darlington array driver IC
such as the ULN2803. The ULN2803 can directly interface to the data
outputs of the decoder IC, and provides much higher drive-current. The
ULN2803 also has internal diode protection that eliminates the need for the fly-back
diode as shown in the above relay driver schematics.
convenience, we have placed the complete datasheet for the ULN2803 HERE.
We have the TWS-434 & RWS-434 RF
transmitters/receivers in-stock with plenty of Holtek remote control ICs to get
you started. Visit our new remote-control store link below.