Remote Control RF Modules.

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JohnCrow
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Remote Control RF Modules.

Postby JohnCrow » Sat Aug 31, 2013 11:16 am

Introduction:

While browsing one of my regular component supplier websites the other day, I spotted these lovely little RF receiver modules.

They have 4 separate outputs, which can be (depending on the version of the board) latching or momentary.
They operate at 315 MHz, and a matching remote keypad is also available.

The Modules are under £5 each and the remote is £5.40

They use the PT2272-M4 (Latching) and SC2272-T4 (Momentary) devices.

The first thing I noticed when I received the modules, was that one side of the main IC was unsoldered.
The supplier confirmed all their stock was like this, and they were tested and working.

On closer examination, it was seen that the pads did not actually have any tracks to them.

The board was connected to a 5V supply, and 4 LEDs and resistors connected to the output pins and down to ground.

Pressing the corresponding key on the remote pad, caused the LED to light.
The range was found to be very good. I could get it to work with the module in the upstairs front and the remote outside at the back of the house.

One downside is the modules as they are supplied are not addressable so if you have more than one board, when you activate the remote, that pin will go high on all powered modules in range.
Though after looking at the data sheet, I believe the IC’s used are capable of being addressed, by means of the unconnected pins on the IC.

They can be obtained in the UK from
http://www.hobbytronics.co.uk

In the States, I believe they can be obtained from Adafruit.

Datasheets for the control devices can be found in various sites, including here.

Latching Board
http://www.adafruit.com/datasheets/PT2272.pdf

Momentary Board
http://www.sc-tech.cn/en/SC2272.pdf

Using With Microcontrollers:

Hardware

Custom 4 x 20 LCD Board.
EB006 Programming Board.
EB016 Prototype Board.
Jumper wires.
LEDs.
Resistor.

The module was connected to the microcontroller PORTA

Out 0 – A3
Out 1 – A2
Out 2 – A1
Out 3 – A0

5V and ground being taken from the EB006

The LCD display was connected to PORT B.
I used my custom board to enable more data to be shown.

A simple Flowcode program was produced to show the binary state of each pin on the display.

A fifth output pin (VT) is also available; this goes high when the received data is valid.
The line is only held high for as long as the RF signal is being received.


Conclusions:

This is not meant to be an in depth project, but just to share the concepts of a usable and inexpensive RF module.

A couple of example flowcharts have been attached using both FC5 and FC6.

Could be a future idea for a FC6 component. :D

Module.jpg
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Protoboard.jpg
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The LED is connected to the VT and lights when a valid data pulse is received.

Control.jpg
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RF Module.zip
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These users thanked the author JohnCrow for the post (total 8):
medelec35 (Sat Aug 31, 2013 11:21 am) • kersing (Sat Aug 31, 2013 11:30 am) • dazz (Sat Aug 31, 2013 2:51 pm) • jgu1 (Sat Aug 31, 2013 8:23 pm) • Benj (Mon Sep 02, 2013 9:28 am) • brandonb (Mon Sep 02, 2013 9:22 pm) • Steve001 (Sat Nov 02, 2013 8:17 pm) • prasha920 (Mon Dec 22, 2014 4:37 pm)
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medelec35
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Re: Remote Control RF Modules.

Postby medelec35 » Sat Aug 31, 2013 11:45 am

Thanks John.

I have been looking for a reasonable priced RF transmitter and receiver.
You have posted a link to one for which I'm grateful.

Just ordered a set :)

As always, thank you for sharing.

Martin
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Re: Remote Control RF Modules.

Postby brandonb » Mon Sep 02, 2013 9:22 pm

for guys in the states they have those at adafruit http://www.adafruit.com/products/1096

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Re: Remote Control RF Modules.

Postby DevinAbbott » Sat Oct 12, 2013 9:11 am

Thanks for sharing detailed information John.. I am looking to get new transmitter and receiver and the information will help me..
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Re: Remote Control RF Modules.

Postby Steve001 » Sat Nov 02, 2013 8:17 pm

Hi John,

Thought of using these little devices and a possible future project after testing a onload tap changer this morning, It would make the job a lot easier and safer .

How did you find the range on them ? the ok for 3 - 4 meters away ? what they like if metal objects in way of 'line of sight' ?

Regards

Steve
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Re: Remote Control RF Modules.

Postby JohnCrow » Sat Feb 22, 2014 10:56 am

The main problem with these modules (which I only realised after buying them and chatting with Martin, are they are not licensed for the UK :x.)

I have just found another source of the RX board which is on 433 MHz, and that is usable in the UK. They only have the non latching version, but it is identical the one I used above apart from the frequency.
Sadly they don't have that nice key fob, but they have this TX board that can soon be wired up on a protoboard with some switches and resistors.

http://hobbycomponents.com/index.php/modu/wireless.html?p=2

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Re: Remote Control RF Modules.

Postby JohnCrow » Tue Jul 25, 2017 8:37 pm

I have just sourced a remote control for these type of modules that works on 433 MHz

This means it is totally legal to us in the UK.

DSC01062b.JPG
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Remote-Test-Switch.fcfx
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Using the above simple test program, the output stays high while the keypad is pressed.

The remote and a 4 channel receiver costs £3.99 inc VAT.
http://www.hobbycomponents.com

For users in the UK they are based in Chesterfield, Derbyshire.

A nice touch on the remote is:

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These users thanked the author JohnCrow for the post (total 4):
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1 in 10 people understand binary, the other one doesn't !