I recently got a RF transmitter/receiver pair from aliexpress.
I did the following video assuming that the receiver was bad!!! Apologies for the bad quality and pace.
However, it turned out to work fine!!! Just not the way I thought it would - the pin mappings were reversed in this case. There also was not much relevant documentation on the seller's page.
So below I will detail some important points about this RF transmitter/receiver pair
General Info
1. It has a encoder/decoder chips built-in. They are necessary for the process of communication. (They use some other chip - not HT12 kind).
2. They network in a different manner. You can pair "remotes" to a receiver and create a network or a channel - i.e a group of transmitters and a receiver that can communicate.
3. Typical applications include toggling a relay that controls your living room light, etc...
I am seriously considering this for two other applications:
1. Remote bike alarm - so I can find my bike in an open bike parking space.
2. Game show buzzer with a team board. When a team presses the buzzer their corresponding team's light indicator should blink.
Modes of operation
It has three modes of operation:
1. Momentary
2. Toggle
3. Latched/Interlocked
Memory Wipe
You can press the learning button 8 times. The LED will flash 7 times to indicate it has reset i.e, forgotten all its previous configuration - all transmitters and its previous mode of operation. This operation is necessary if you want to change modes. However, after doing this, you have to re-pair all your transmitters.
Learning Mode
After a memory wipe you have to first set the receiver into learning mode and then program it to one of the above mentioned modes.
To set it in a momentary mode: Press the learning button once. Wait for the LED to turn on. (This indicates its in a learning mode). On the transmitter, push any button. Or more accurately, ground a pin. Wait for the above LED to flash 3 times. (This indicates it has accepted the setting and it has come out of the learning mode). Now it is ready for normal operation.
To set it in toggle mode: Hit the learning mode button 2 times. Rest of the process remains same as above.
To set it in latched mode: Hit the learning mode button 3 times. Rest of the process remains same as above.
Configuring more transmitters
Otherwise also called "pairing". The process is exactly similar to "learning". You "toggle" the receiver into the (corresponding) learning mode. Press any button on the new transmitter. Wait for it to exit the learning mode. And you are done.
Prototype setup for testing the momentary mode of usage.
Stuff you need
1. jumper wires
2. breadboard
3. 5V/3.3V DC power supply module (comes with a 12V adapter)
4. 5 x LED
5. 5 x 330 Ohm Resistor
6. 4 x Momentary push button
Wiring
Note: no need to connect antennae now. Its only important for range test or applications that require a long distance.
Momentary mode operation
1. Wipe Memory first.
2. Undergo "learning" for the momentary operation mode.
3. Test different buttons on the transmitter, and, see the corresponding LEDs on the receiver end light up.
Its that simple.
The alternate learning button
You can have the VT pin on the receiver pulled high through a 1k Ohm resistor momentarily to simulate a learning mode button press. Consider this alternative when you find pressing the small button on the board cumbersome.
Have a nice day.
Extras
Video showing different modes: https://www.youtube.com/watch?v=4uW7vx6JnxISeller listing page: https://www.aliexpress.com/item/4000064795450.html
Post an image of your breadboard if you like... ;)
Yes. I also performed a range test at my work place - Infosys Bangalore Main Campus. Got a range of about 290 m. (Line of sight).
