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I NEED HELP! HOW DO I MOD. A UHF 2 CHANNEL RECEIVER ......

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JC

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I HAVE A 2 CHANNEL UHF RECIEVER AND I WANT TO CHANGE IT SO WHEN I PUSH THE BUTTON ON THE REMOTE THE RELAY TOGGLES MOMENTARILY INSTEAD OF JUST ON OR OFF. SOMEONE TOLD ME TO REMOVE THE RELAY & REPLACE IT WITH A CAPACITOR & RESISTOR DIODE BUT DIDN'T GIVE MET ANY VALUES BELOW IS INFO ON THE KIT I HAVE:

This kit allows a 2 button key-ring UHF transmitter to toggle two relays on/off on a receiver board up to 40 meters away. The frequency of transmission is preset at about 318MHz but it can be easily adjusted anywhere between 300MHz to 375MHz.

Transmitter in case. This comes already assembled and tested with its own 12V battery included. When you press either one of the buttons the red LED should light up. Later you may need to open the case to adjust the frequency for maximum distance or to solder in some jumpers to set a code. The unit comes with no jumpers set.

Receiver Module: The pre-built module solders directly into the receiver PCB. Note that the decoder IC doesn't fit on this module. The decoder IC goes on the main receiver board.

Receiver PCB: There are two pairs of PADS. They are provided in case you want to disable one relay then reconnect it at a later date. They are already connected on the copper layer by a track. To disconnect a relay just cut the copper track with a cutter. When you first assemble the board leave them unconnected and the track uncut.

Power supply to the board is 12V - 15V. The top pad is positive. (The overlay indicating this was forgotten) The bottom pad is ground. The 3mm red LED should turn on when power is connected. Pressing the transmitter buttons should toggle the relays on/off.

Calibration: Undo the aerial on the receiver module. Test what distance you get. For the most range we found it best to adjust the trimcap in the transmitter as you walk further away from it. We could get over 30 meters.

CIRCUIT DESCRIPTION
Transmitter: When either switch is closed power is applied to the encoder IC, A5884, to the LED and to an oscillator coil. The A5884 has 10 address but and two data bits The 12 bits of trinary information are serially transmitted on pin 17 when either data pin is taken low by pressing the switch. The ten address lines can be tied high, low or left floating. As supplied all are left floating. It is easy to tie some or all of A0 to A9 to ground since a ground track has been provided on the transmitter PCB right next to these pins. To allow for easy matching of a code we have provided a similar ground nest to the decoder IC. A trimcap on the tank circuit can vary the output frequency between 300MHz and 375 MHz approx.

Receiver: It is based on a complete front-end module which processes the signal via a bandpass filter, amplifier and Schmitt trigger. Its output delivers a digital pulse train to the input of the decoder IC. Normally pin 17 is low. This pulls down the clock inputs to the 4013 to about 0.6V which is the voltage drop across D2 & D3. Pins 12 & 13 are normally high.
When the decoder IC receives data with a valid address code, pin 17 goes high, and pin 12 or 13 goes low according to whichever of the corresponding pins on the encoder IC was pressed. Let us assume button 11 is pressed on the transmitter. Pin 12 on the decoder IC goes low. Pin 13 remains high. But on the other side of the 100K resistor on Pin 13 the line is now pulled high via D2 to pin 17. So the clock input pin 3 goes high, and relay 1 is closed.
The flip-flops (FF) are connected to toggle each time a positive going pulse appears at the clock input. This is done by connecting the Q/ output to the D input via an RC network. The time constant of this network plus the C5 & C7 capacitors prevent false triggering due to noise.
When power is applied, IC2, the 4013, is reset by C8 & R18. Reset is caused by sending the reset inputs of IC2 high. The Q output of each FF connects to a driver transistor via a 3K3 resistor. When Q is high the transistor is turned on and the relay is closed. Protection diodes are connected across each relay coil to limit the back EMF when the relay is de-energized.
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arcom

New Member
Try removing the 4013 IC and connect (on PCB) CLOCK pin to Q output.
Assuming you have only one IC on the board (since 4013 is a dual flip-flop), connect pin 3 to 1 and 11 to 13.
 
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