Blaze
10 command radio control on MRF49XA.
The design is based on relatively new and inexpensive microcircuits MRF49XA.
One is used in the receiving part, the other in the transmitting part.
Transmitter circuit.
Consists of a control controller and a transceiver MRF49XA.
Receiver circuit.
Assembled from the same elements as the transmitter. In practice, the difference between the receiver and the transmitter (not taking into account the LEDs and buttons) consists only in the software part.
MRF49XA- a small-sized transceiver that can operate in
three frequency ranges.
Low frequency range: 430.24 - 439.75 MHz(2.5 kHz step) .
High frequency range A: 860.48 - 879.51 MHz(5 kHz step) .
High frequency range B: 900.72 - 929.27 MHz(7.5 kHz step) .
The range limits are indicated subject to the use of a reference quartz with a frequency of 10 MHz,
provided by the manufacturer. With 11 MHz reference quartz, the devices operated normally at a frequency of 481 MHz. Detailed studies on the maximum “tightening” of the frequency relative to that declared by the manufacturer were not carried out. Presumably, it may not be as wide as in the TXC101 chip, since in the datasheet MRF49XA Mention is made of reduced phase noise, one way to achieve which is to narrow the tuning range of the VCO.
The devices have the following technical characteristics.
Transmitter.
Power - 10 mW.
up to 5 volts).
The current consumed in transmission mode is 25 mA.
Quiescent current - 25 µA.
Data speed - 1kbit/sec.
An integer number of data packets are always transmitted.
FSK modulation.
Noise-resistant coding, checksum transmission.
Receiver.
Sensitivity - 0.7 µV.
Supply voltage 2.2 - 3.8 V (according to the datasheet on ms, in practice it works fine
up to 5 volts).
Constant current consumption - 12 mA.
Data speed up to 2 kbit/sec. Limited by software.
FSK modulation.
Noise-resistant coding, checksum calculation upon reception.
Work algorithm.
The ability to press any combination of any number of transmitter buttons at the same time. The receiver will display the pressed buttons in real mode with LEDs. Simply put, while a button (or combination of buttons) on the transmitting part is pressed, the corresponding LED (or combination of LEDs) on the receiving part is lit.
The button (or combination of buttons) is released - the corresponding LEDs immediately go out.
Test mode.
Both the receiver and the transmitter, upon supplying power to them, enter test mode for 3 seconds.
Both the receiver and the transmitter are switched on to transmit the carrier frequency programmed in the EEPROM for 1 second 2 times with a pause of 1 second (during the pause the transmission is turned off). This is convenient when programming devices. Next, both devices are ready for use.
Controller programming.
EEPROM of the transmitter controller.
The top line of the EEPROM after flashing the firmware and supplying power to the transmitter controller will look like this...
98 F0 - (maximum transmitter power, deviation 240 kHz) - Tx Config RG
82 39 - (transmitter on) - Pow Management RG.
10 h) - identifier.
Default here FF. The identifier can be anything within a byte (0 ... FF). This is the individual number (code) of the remote control.
At the same address in the memory of the receiver controller is its identifier. They must match. This makes it possible to create different receiver/transmitter pairs.
Receiver controller EEPROM.
All EEPROM settings mentioned below will be written automatically into place as soon as power is supplied to the controller after its firmware is updated.
The data in each cell can be changed at your discretion. If you enter FF into any cell used for data (except the identifier), the next time the power is turned on, this cell will immediately be overwritten with default data.
The top line of the EEPROM after flashing the firmware and supplying power to the receiver controller will look like this...
80 1F - (4xx MHz subband) - Config RG
AC 80 - (exact frequency value 438 MHz) - Freg Setting RG
91 20 - (receiver bandwidth 400 kHz, maximum sensitivity) - Rx Config RG
C6 94 - (data speed - no faster than 2 kbit/sec) - Data Rate RG
C4 00 - (AFC disabled) - AFG RG
82 D9 - (receiver on) - Pow Management RG.
The first memory cell of the second row (address 10 h) - receiver identifier.
To correctly change the contents of registers of both the receiver and transmitter, use the program RFICDA by selecting the chip TRC102 (this is a clone of MRF49XA).
Notes
In the photo of the transmitter, the track of the positive power bus of the controller is cut and duplicated with a wire. This is done to prevent short circuits through the metal housings of the buttons (this was not taken into account during the design).
The reverse side of the boards is a solid mass (tinned foil).
The range of reliable operation in line of sight conditions is 200 m.
The number of turns of coils prm and prd is 6. If you use an 11 MHz reference crystal instead of 10 MHz, the frequency will “go” higher than about 40 MHz. Maximum power and sensitivity in this case will be with 5 turns of circuits prm and prd.
The firmware is free to download, without any restrictions. Any copyright - with a mandatory link to website.
What I would like to say on my own is that it is an excellent solution in any remote control situation. First of all, this applies to situations where there is a need to manage a large number of devices at a distance. Even if you don’t need to control a large number of loads at a distance, it’s worth doing the development, since the design is not complicated! A couple of not rare components are a microcontroller PIC16F628A and microcircuit MRF49XA - transceiver
A wonderful development has been languishing on the Internet for a long time and is gaining positive reviews. It was named in honor of its creator (10 command radio control on mrf49xa from blaze) and is located at -
Below is the article:
Transmitter circuit:
Consists of a control controller and a transceiver MRF49XA.
Receiver circuit:
The receiver circuit consists of the same elements as the transmitter. In practice, the difference between the receiver and the transmitter (not taking into account the LEDs and buttons) consists only in the software part.
A little about microcircuits:
MRF49XA- a small-sized transceiver that has the ability to operate in three frequency ranges.
1. Low frequency range: 430.24 - 439.75 MHz(2.5 kHz step).
2. High frequency range A: 860.48 - 879.51 MHz(5 kHz step).
3. High frequency range B: 900.72 - 929.27 MHz(7.5 kHz step).
The range limits are indicated subject to the use of a reference quartz with a frequency of 10 MHz, provided by the manufacturer. With 11 MHz reference crystals, the devices operated normally at 481 MHz. Detailed studies on the topic of the maximum “tightening” of the frequency relative to that declared by the manufacturer have not been carried out. Presumably, it may not be as wide as in the TXC101 chip, since in the datasheet MRF49XA Mention is made of reduced phase noise, one way to achieve which is to narrow the tuning range of the VCO.
The devices have the following technical characteristics:
Transmitter.
Power - 10 mW.
The current consumed in transmission mode is 25 mA.
Quiescent current - 25 µA.
Data speed - 1kbit/sec.
An integer number of data packets are always transmitted.
FSK modulation.
Noise-resistant coding, checksum transmission.
Receiver.
Sensitivity - 0.7 µV.
Supply voltage - 2.2 - 3.8 V (according to the datasheet for ms, in practice it works normally up to 5 volts).
Constant current consumption - 12 mA.
Data speed up to 2 kbit/sec. Limited by software.
FSK modulation.
Noise-resistant coding, checksum calculation upon reception.
Work algorithm.
The ability to press any combination of any number of transmitter buttons at the same time. The receiver will display the pressed buttons in real mode with LEDs. Simply put, while a button (or combination of buttons) on the transmitting part is pressed, the corresponding LED (or combination of LEDs) on the receiving part is lit.
When a button (or combination of buttons) is released, the corresponding LEDs immediately go out.
Test mode.
Both the receiver and the transmitter, upon supplying power to them, enter test mode for 3 seconds. Both the receiver and the transmitter are switched on to transmit the carrier frequency programmed in the EEPROM for 1 second 2 times with a pause of 1 second (during the pause the transmission is turned off). This is convenient when programming devices. Next, both devices are ready for use.
Controller programming.
EEPROM of the transmitter controller.
The top line of EEPROM after flashing and supplying power to the transmitter controller will look like this...
80 1F - (4xx MHz subband) - Config RG
AC 80 - (exact frequency value 438 MHz) - Freg Setting RG
98 F0 - (maximum transmitter power, deviation 240 kHz) - Tx Config RG
82 39 - (transmitter on) - Pow Management RG.
The first memory cell of the second row (address 10 h) — identifier. Default here FF. The identifier can be anything within a byte (0 ... FF). This is the individual number (code) of the remote control. At the same address in the memory of the receiver controller is its identifier. They must match. This makes it possible to create different receiver/transmitter pairs.
Receiver controller EEPROM.
All EEPROM settings mentioned below will be written automatically into place as soon as power is supplied to the controller after its firmware is updated.
The data in each cell can be changed at your discretion. If you enter FF into any cell used for data (except ID), the next time the power is turned on, this cell will immediately be overwritten with default data.
The top line of EEPROM after flashing the firmware and supplying power to the receiver controller will look like this...
80 1F - (4xx MHz subband) - Config RG
AC 80 - (exact frequency value 438 MHz) - Freg Setting RG
91 20 — (receiver bandwidth 400 kHz, maximum sensitivity) — Rx Config RG
C6 94 - (data speed - no faster than 2 kbit/sec) - Data Rate RG
C4 00 - (AFC disabled) - AFG RG
82 D9 - (receiver on) - Pow Management RG.
The first memory cell of the second row (address 10 h) — receiver identifier.
To correctly change the contents of registers of both the receiver and transmitter, use the program RFICDA by selecting the chip TRC102 (this is a clone of MRF49XA).
Notes
The reverse side of the boards is a solid mass (tinned foil).
The range of reliable operation in line of sight conditions is 200 m.
The number of turns of the receiver and transmitter coils is 6. If you use an 11 MHz reference crystal instead of 10 MHz, the frequency will “go” higher than about 40 MHz. Maximum power and sensitivity in this case will be with 5 turns of the receiver and transmitter circuits.
My implementation
At the time of implementation of the device, I had a wonderful camera at hand, so the process of making a board and installing parts on the board turned out to be more exciting than ever. And this is what it led to:
The first step is to make a printed circuit board. To do this, I tried to dwell in as much detail as possible on the process of its manufacture.
We cut out the required size of the board. We see that there are oxides - we need to get rid of them. The thickness was 1.5 mm.
The next stage is cleaning the surface; for this you should select the necessary equipment, namely:
1. Acetone;
2. Sandpaper (zero grade);
3. Eraser
4. Means for cleaning rosin, flux, oxides.
Acetone and means for washing and cleaning contacts from oxides and experimental board
The cleaning process occurs as shown in the photo:
Using sandpaper we clean the surface of the fiberglass laminate. Since it is double-sided, we do everything on both sides.
We take acetone and degrease the surface + wash off the remaining sandpaper crumbs.
And veil - a clean board, you can apply a signet using the laser-iron method. But for this you need a signet :)
Cutting out from the total amount Trimming off the excess
We take the cut out seals of the receiver and transmitter and apply them to the fiberglass as follows:
Type of signet on fiberglass
Turning it over
We take the iron and heat the whole thing evenly until a trace appears on the back side. IMPORTANT NOT TO OVERHEAT!Otherwise the toner will float! Hold for 30-40 seconds. We evenly stroke the difficult and poorly heated areas of the signet. The result of a good transfer of toner to fiberglass is the appearance of an imprint of tracks.
Smooth and weighty base of the iron Apply a heated iron to the signet
We press the signet and translate.
This is what the finished printed sign looks like on the second side of glossy magazine paper. The tracks should be visible approximately as in the photo:
We perform a similar process with the second signet, which in your case can be either a receiver or a transmitter. I placed everything on one piece of fiberglass
Everything should cool down. Then carefully remove the paper with your finger under running water. Roll it with your fingers using slightly warm water.
Under slightly warm water Roll up the paper with your fingers Cleaning result
Not all paper can be removed this way. When the board dries, a white “patina” remains, which, when etched, can create some unetched areas between the tracks. The distance is small.
Therefore, we take thin tweezers or a gypsy needle and remove the excess. The photo shows it great!
In addition to the remains of paper, the photo shows how, as a result of overheating, the contact pads for the microcircuit have stuck together in some places. They need to be carefully separated, using the same needle, as carefully as possible (scraping off part of the toner) between the contact pads.
When everything is ready, we move on to the next stage - etching.
Since we have double-sided fiberglass and the reverse side is a solid mass, we need to keep the copper foil there. For this purpose, we will seal it with tape.
Adhesive tape and protected board The second side is protected from etching by a layer of adhesive tape Electrical tape as a “handle” for easy etching of the board
Now we etch the board. I do this the old fashioned way. I dilute 1 part ferric chloride to 3 parts water. All the solution is in the jar. Convenient to store and use. I heat it up in the microwave.
Each board was etched separately. Now we take the already familiar “zero” in our hands and clean the toner on the board
Many people wanted to assemble a simple radio control circuit, but one that would be multifunctional and for a fairly long distance. I finally put together this circuit, spending almost a month on it. I drew the tracks on the boards by hand, since the printer does not print such thin ones. In the photo of the receiver there are LEDs with uncut leads - I soldered them only to demonstrate the operation of the radio control. In the future I will unsolder them and assemble a radio-controlled airplane.
The radio control equipment circuit consists of only two microcircuits: the MRF49XA transceiver and the PIC16F628A microcontroller. The parts are basically available, but for me the problem was the transceiver, I had to order it online. and download the payment here. More details about the device:
MRF49XA is a small-sized transceiver that has the ability to operate in three frequency ranges.
- Low frequency range: 430.24 - 439.75 MHz (2.5 kHz step).
- High frequency range A: 860.48 - 879.51 MHz (5 kHz step).
- High frequency range B: 900.72 - 929.27 MHz (7.5 kHz step).
The range limits are indicated subject to the use of a reference quartz with a frequency of 10 MHz.
Schematic diagram of the transmitter:
The TX circuit has quite a few parts. And it is very stable, moreover, it does not even require configuration, it works immediately after assembly. The distance (according to the source) is about 200 meters.
Now to the receiver. The RX block is made according to a similar scheme, the only differences are in the LEDs, firmware and buttons. Parameters of the 10 command radio control unit:
Transmitter:
Power - 10 mW
Supply voltage 2.2 - 3.8 V (according to the datasheet for m/s, in practice it works normally up to 5 volts).
The current consumed in transmission mode is 25 mA.
Quiescent current - 25 µA.
Data speed - 1kbit/sec.
An integer number of data packets are always transmitted.
Modulation - FSK.
Noise-resistant coding, checksum transmission.
Receiver:
Sensitivity - 0.7 µV.
Supply voltage 2.2 - 3.8 V (according to the datasheet for the microcircuit, in practice it works normally up to 5 volts).
Constant current consumption - 12 mA.
Data speed up to 2 kbit/sec. Limited by software.
Modulation - FSK.
Noise-resistant coding, checksum calculation upon reception.
Advantages of this scheme
The ability to press any combination of any number of transmitter buttons at the same time. The receiver will display the pressed buttons in real mode with LEDs. Simply put, while a button (or combination of buttons) on the transmitting part is pressed, the corresponding LED (or combination of LEDs) on the receiving part is lit.
When power is supplied to the receiver and transmitter, they go into test mode for 3 seconds. At this time nothing works, after 3 seconds both circuits are ready for operation.
The button (or combination of buttons) is released - the corresponding LEDs immediately go out. Ideal for radio control of various toys - boats, planes, cars. Or it can be used as a remote control unit for various actuators in production.
On the transmitter circuit board, the buttons are located in one row, but I decided to assemble something like a remote control on a separate board.
Both modules are powered by 3.7V batteries. The receiver, which consumes noticeably less current, has a battery from an electronic cigarette, the transmitter - from my favorite phone)) I assembled and tested the circuit found on the VRTP website: [)eNiS
Discuss the article RADIO CONTROL ON A MICROCONTROLLER
In this article, you will see how to make a radio control for 10 commands with your own hands. The range of this device is 200 meters on the ground and more than 400m in the air. The buttons can be pressed in any order, although everything works stably at once. Using it, you can control different loads: garage doors, lights, model airplanes, cars, and so on... In general, anything, it all depends on your imagination.
For work we need a list of parts:
1) PIC16F628A-2 pcs (microcontroller)
2) MRF49XA-2 pcs (radio transmitter)
3) 47nH inductor (or wind it yourself) - 6 pcs
Capacitors:
4) 33 uF (electrolytic) - 2 pcs.
5) 0.1 uF-6 pcs
6) 4.7 pF-4 pcs
7) 18 pF - 2 pcs
Resistors
8) 100 Ohm - 1 piece
9) 560 Ohm - 10 pcs
10) 1 Com-3 pieces
11) LED - 1 piece
12) buttons - 10 pcs.
13) Quartz 10MHz-2 pcs
14) Textolite
15) Soldering iron
Here is the diagram of this device
Transmitter
And the receiver
As you can see, the device consists of a minimum of parts and can be done by anyone. You just have to want it. The device is very stable, after assembly it works immediately. The circuit can be made as on a printed circuit board. Same with mounted installation (especially for the first time, it will be easier to program). First, we make the board. Print it out
And we poison the board
We solder all the components, it is better to solder PIC16F628A as the last one, since it will still need to be programmed. First of all, solder the MRF49XA
The main thing is to be very careful, she has very subtle conclusions. Capacitors for clarity. The most important thing is not to confuse the poles on the 33 uF capacitor since its terminals are different, one is +, the other is -. All other capacitors can be soldered as you wish, they have no polarity on the terminals
You can use purchased 47nH coils, but it’s better to wind them yourself, they are all the same (6 turns of 0.4 wire on a 2 mm mandrel)
When everything is soldered, we check everything well. Next we take PIC16F628A, it needs to be programmed. I used PIC KIT 2 lite and a homemade socket
Here is the connection diagram
It's all simple, so don't be scared. For those who are far from electronics, I advise you not to start with SMD components, but to buy everything in DIP size. I did this myself for the first time
And it all really worked the first time
Open the program, select our microcontroller
Click insert firmware file and click WRITE
The same applies to other microcontrollers.
The TX file is for the transmitter and the RX is for the receiver. The main thing is not to confuse the microcontrollers later. And we solder the microcontrollers onto the board. After assembling, under no circumstances connect the load directly to the board, otherwise you will burn everything. The load should be connected to the board through a powerful transistor as in the photo
The LEDs in the diagram are purely for testing functionality. If anyone doesn’t have a programmer, please contact me, I’ll help you with already flashed chips.
website
Contacts:
Address: Tovarnaya, 57-V, 121135, Moscow,
Phone: +7 971-129-61-42, Email: [email protected]
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