433 MHz RF Module interfacing with Encoder and Decoder Problem

Thread Starter

Leonard Lim

Joined Oct 8, 2019
6
I had use 433 Mhz RF module with transmitter (FS1000A) and receiver (MX-RM-5V). Interfacing with Encoder (HT12E) and decoder (HT12D) respectively. The problem is that I am using two sets of these set up in circuit one and two. Which means the first circuit having encoder with the same address as the decoder in the second circuit and vice versa. Is it two RF module won't be interrupted by the two receiver side as long as their address is not the same?

(I know I should of use transceiver instead but still attempt to do this). Thanks in advance
 

AlbertHall

Joined Jun 4, 2014
10,249
By setting different addresses for the two systems, each system will ignore messages addressed to the other system. However, if they both transmit at the same time they will interfere with each other. That might mean that neither message is received correctly, or possibly just one of them may be received correctly. They will not both be correct.

This is assuming that they are within range of each other.
 

Thread Starter

Leonard Lim

Joined Oct 8, 2019
6
By setting different addresses for the two systems, each system will ignore messages addressed to the other system. However, if they both transmit at the same time they will interfere with each other. That might mean that neither message is received correctly, or possibly just one of them may be received correctly. They will not both be correct.

This is assuming that they are within range of each other.
Nice explanation and understood. There is another question. What if circuit 1 transmitter wants to send data bits to circuit 2 and at the same time before sending the data bits. Switching off the Vcc of the receiver in circuit 1 via transistor switching and vice versa. Does this methodology help to get both correct? (After sending data bits when circuit 2 wants to send data bits, switch off the Vcc of the receiver in circuit 2 and switch back on the circuit 1 receiver)
PS: My project does need the two RF modules within the range of each other. Both of circuit does not need to transmit and receive at the same time
 

AlbertHall

Joined Jun 4, 2014
10,249
You have two transmitters and two receivers - please confirm.
Which of the following do you want to be able to do:
1. Transmitter 1 sends messages to receiver 1.
2. Transmitter 1 sends messages to receiver 2.
3. Transmitter 2 sends messages to receiver 1.
4. Transmitter 2 sends messages to receiver 2.
 

Thread Starter

Leonard Lim

Joined Oct 8, 2019
6
You have two transmitters and two receivers - please confirm.
Which of the following do you want to be able to do:
1. Transmitter 1 sends messages to receiver 1.
2. Transmitter 1 sends messages to receiver 2.
3. Transmitter 2 sends messages to receiver 1.
4. Transmitter 2 sends messages to receiver 2.
Circuit (1) Transmitter 1 to Circuit (2) receiver 2
Circuit (2) Transmitter 2 to Circuit (1) receiver 1
 
Last edited:

AlbertHall

Joined Jun 4, 2014
10,249
It doesn't matter whether the receivers are enabled or not, the two transmitters must not transmit at the same time. If they do any reception will be garbled.
 

MrChips

Joined Oct 2, 2009
21,682
You are attempting to create a full-duplex RF communications link.
Designate one circuit as the master. Only the master is allowed to begin transmission. The slave circuit responds to messages received from the master circuit.
 

Phil-S

Joined Dec 4, 2015
146
For what it's worth, I never got these Holtek chips to work reliably.
For 433-mHz applications, I always use RF Solutions RF803E encoder chip with RF803D decoder.
They are based on a Microchip MCU
 
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