433.92 MHz RF Remote Control

Visit our new page for complete schematics of infrared, RF remote control, Holtek encoder/decoder ICs, and relay control projects. HERE

Below are schematics & projects using the TWS/RWS RF modules:

	8-Bit Transmitter Schematic: Click HERE
	8-Bit Receiver Schematic: Click HERE
	Simple 5-Switch, 4-Bit Transmitter: (shown below)
	4-Bit Receiver For DC Motor Control: Click HERE
	Simple Relay Control Circuit: Click HERE
	Freddy — The Robot Bug Killer: Click HERE
	Ruf-Bot — RF Remote Controlled Robot: Click HERE
	BASIC Stamp Wireless Communications: Click HERE

Receiver circuits are using NPN transistors.  Substitute for PNP transistors if necessary.

Question: Can I use the TWS-434 & RWS-434 RF modules for serial communications..?

Answer: You bet.  Click HERE for a complete project using these modules to control a hobby robot using a PC joystick with PicBasic & asynchronous serial control techniques.

Question: Where can I buy the TWS-434 & RWS-434 RF modules..?

Answer: Right HERE……..

The 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.

TWS-434:  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…..

TWS-434A

The TWS-434 transmitter accepts both linear and 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

RWS-434:  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 digital outputs.

Click on picture for larger image

RWS-434 Receiver

RWS-434 Pin Diagram

Note: For 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

The 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:

Click HERE to download the RWS & TWS datasheet in Adobe PDF format.

Driving Relays:

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

TIP: 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.

For your 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.

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