Chinese radio control circuits for models. Radio-controlled model from scratch

Hello everyone, three months ago - while sitting “on the answers to mail ru” I came across a question: http://otvet.mail.ru/question/92397727, after the answer I gave, the author of the question began to write to me in a personal message, from the correspondence it became known that Comrade “Ivan Ruzhitsky”, also known as “STAWR”, builds a remote control car whenever possible without “expensive” factory hardware.

From what he purchased, he had RF modules at 433 MHz and a “bucket” of radio components.

I wasn’t exactly “sick” with this idea, but I still began to think about the possibility of implementing this project from the technical side.
At that time, I was already quite well versed in the theory of radio control (I think so), in addition; some developments were already in service.

Well, for people who are interested - the Administration came up with a button......

So:
All the nodes were made “on the knee”, so there is no “beauty”, the main task is to find out how feasible this project is and how much it will “come out” in rubles and in labor.

REMOTE CONTROLLER:
I didn’t make a homemade transmitter for two reasons:
1. Ivan already has it.
2. Once I tried to stir up 27 MHz - nothing good came of it.
Since the control was intended to be proportional, all sorts of remote controls from Chinese rubbish disappeared by themselves.

I took the encoder circuit (channel encoder) from this site: http://ivan.bmstu.ru/avia_site/r_main/HWR/TX/CODERS/3/index.html
Thank you very much to the authors, it was because of this device that I had to learn how to “flash” the MK.
I bought the transmitter and receiver right there at Park, although at 315 MHz, I just chose the cheaper one:
The website with the encoder has everything you need - the circuit itself, a printed circuit board “for ironing” and a whole bunch of firmware with various costs.

The body of the remote control is soldered from fiberglass, the sticks were taken from a helicopter remote control with IR control, it was also possible from a computer gamepad, but my wife would kill me, she plays “DmC” on it, the battery compartment is from the same remote control.

There is a receiver, but in order for the car to move, you also need a decoder (channel decoder), so I had to look for it for a very long time - even Google was sweating, well, as they say, “let the seeker find” and here it is: http://homepages .paradise.net.nz/bhabbott/decoder.html

There are also firmwares for MK.

Regulator: Initially I made the simpler one:

But driving only in front is not ice and this one was chosen:

Link to website: http://vrtp.ru/index.php?showtopic=18549&st=600
The firmware is also there.

I searched through a mountain of motherboards and video cards and did not find the necessary transistors, namely for the upper arm (P-channel), so the H-bridge (this is the unit that powers the motor) was soldered on the basis of a Toshiba microcircuit from the “TA7291P” video recorder,

the maximum current is 1.2A - which suited me quite well (not TRAXXAS - I do it), I drew the board with a marker for 20 rubles, etched it with ferric chloride, soldered it from the side of the tracks. This is what happened.

“Pure” PRM is emitted into the air, of course this is not good, I won’t put this on an airplane, but for a toy it will do just fine.
The car was taken from the factory, from the Chinese brothers, the entire tribune except the running engine was removed and in its place they put in my and Ivan’s project, even though we are busy with it separately, it was his idea!

Spent:
Set of RF modules – 200 RUR
Two PIC12F675 MKs - 40 rubles each.
Serva - TG9e 75r
+3 pm.

If you have any questions, I’ll be happy to answer (I didn’t write about many things)
Best regards, Vasily.

Basic technical data

The radio control system allows you to remotely control the toy at a distance of up to 10 meters.
The operating frequency of the transmitter is 27.12 MHz.
Transmitter power is within 4-10 mW.
Transmitter current consumption is no more than 20 mA.
The weight of the transmitter with antenna and power supply is no more than 150 g.
The sensitivity of the receiver in the operating frequency band is no worse than 100 µV.
Receiver current consumption is no more than 20 mA.
The weight of the receiver is no more than 70 g.
The command apparatus ensures the execution of four different commands, which are repeated periodically.
The weight of the command device is no more than 70 g.
The receiver and transmitter are powered by Krona-VTs batteries.

Principle of operation

The transmitter consists of a modulator and a high-frequency generator (Fig. 1). The transmitter modulator is symmetrical multivibrator, collected at low frequency transistors VT2 and VT3 MP40 type.

The high-frequency generator is assembled on a P416 type transistor VT1 according to a capacitive circuit feedback. When the modulator transistor VT2 is open, the generator circuit is closed to the battery positive, the generator is excited at the operating frequency, and the high-frequency signal is emitted by the antenna.

The receiver consists of a high-frequency stage, a low-frequency amplifier and an electronic relay.

The high-frequency stage of the receiver is a super-regenerator. The super-regenerator is assembled on a high-frequency transistor VT1 type P416 (Fig. 2).

In the absence of a signal on the emitter circuit C5 R3, fluctuations in the quenching frequency are observed. The quenching frequency determines the sensitivity of the superregenerator at its operating frequency and is selected by elements C5, R3.

The transmitter command signal is isolated by the L1-C4 circuit, amplified and detected by a super-regenerator. Filter R4-C8 passes the low-frequency command signal to the input of amplifier VT2, while separating the higher-order blanking frequency.

The electronic relay is assembled on transistors VT3-VT4 type MP40, and the collector of transistor VT4 is connected to the executive relay KR type RSM-1.

The low frequency voltage of the command signal is amplified by transistors VT3-VT4 and supplied through capacitor C13 to the rectifier cell UD1, UDZ.

The rectified voltage through resistor R9 is supplied to the base of transistor VT3. In this case, the emitter current of transistor VT3 increases sharply, transistor VT4 opens. The relay is activated, closing the power supply circuit of the command device motor.

The command device consists of an electric motor, a ratchet mechanism, a program disk and distribution sliding contacts. The program disk, the side of which is a system of jumpers, switches power to the drive motors and other electrical elements of the toy through distribution sliding contacts.

Description electrical diagram radio controlled toy

The diagram (Fig. 3) shows one of the electrical equipment options for a radio-controlled toy.

The toy has two drive motors that provide forward movement and turns left and right. Light bulbs rear lights toys serve as turn signals. Two headlights create the effect of illuminating the path of the toy.

Fig.3

To receive command signals from the transmitter, a receiver and a Command Device are built into the toy. The drive and control motor, as well as the light bulbs, are powered by two series-connected batteries of type 3336L(U) (GB1). The receiver is powered by a Krona-VTs battery (GB2). To turn off the battery, use a two-pole switch S. When a command signal is received from the transmitter, the relay KR, the receiver is activated and its contacts turn on the electric motor of the command apparatus (Fig. 4) MZ.

Fig.4. Command apparatus

The MZ electric motor, using a ratcheting mechanism, rotates the program disk by 30°, which corresponds to switching one command.

The program disk, through distributive sliding contacts, turns on the drive motors and toy lights as follows:

In the “forward” position, contacts 1, 2, 3, 4 are closed, while the motors M1 and M2 are turned on, as well as the bulbs H1, H2, NC, H4.

In the “right” position, contacts 1, 2 are closed, while the M1 motor and the NC lamp are turned on.

In the "stop" position, all contacts are open.

In the “left” position, contacts 1, 3 are closed, while the M2 motor and the H4 light bulb are turned on.

Teams change periodically. The diagram shows the sequence of commands in one cycle.

Instructions for installation and commissioning of the system

It is advisable to place the receiver in the toy at the maximum distance from the electrical system. motors and electromagnets. To protect the receiver from interference generated by electric motors, it is recommended to connect 10-20 uF electrolytic capacitors with an operating voltage of 10-12 volts in parallel with the electric motors, observing the polarity of the connection. An antenna must be connected to the receiver. A pin or wire with a diameter of 1.0-2.0 mm and a length of at least 20 cm can be used as an antenna. The antenna must be isolated from the body of the toy. Parts made of ceramics, fluoroplastic, plexiglass or polystyrene can be used as insulators. As the antenna length increases, the control range increases. The receiver must be covered with a cover made of insulating material to protect it from dust and moisture. The distance from the printed circuit board to the base on which the receiver is mounted must be at least 5 mm.
After installing the electrical circuit and checking its functionality (the switching procedure is indicated below), it is necessary to adjust the receiver to maximum sensitivity. The adjustment is made using capacitor C4 (see. schematic diagram and receiver drawing). By turning the capacitor rotor with an insulating screwdriver, you need to find the position at which the relay operates when the transmitter is removed as far as possible.

The command device is fixed on a horizontal platform using claws.

Dear 4uvak. The other day I collected this miracle for 4 channels. I used the FS1000A radio module. Of course, everything works as written, except for the range, but I think this radio module is simply not a fountain, that’s why it costs $1.5.
But I assembled it in order to bind it to broadlink rm2 pro and it didn’t work out for me. Broadlink rm2 pro saw it, read its command and saved it, but when it sends the command to the decoder, the latter does not react in any way. Broadlink rm2 pro is designed according to the stated characteristics to operate in the 315/433 MHz range, but it did not accept this miracle into its ranks. This was followed by dancing with a tambourine..... The broadlink rm2 pro has a function as a timer for several commands and I decided to set the broadlink rm2 pro a task to send the same command several times with an interval of 0 seconds, BUT!!! Having written down one command, he refused to write it down further, citing the fact that there was no more memory space to save the commands. Next, I tried to do the same operation with commands from the TV and it recorded 5 commands without problems. From this I concluded that in the program you wrote, the commands sent by the encoder to the decoder are very informative and large in scope.

I am an absolute zero in MK programming and your project is the first assembled and working remote control in my life. I have never been friendly with radio technology and my profession is far from electronics.

Now the question:

If, as I believe, the signal sent by the encoder is long and large, then it can be made as miniscule as possible???, with the same base, so as not to change the MK wiring and circuit.

I understand that any unpaid work is considered slavery :))))), and therefore I am ready to pay for your work. Of course, I don’t know how much it will cost, but I think the price will be adequate for the work done. I wanted to transfer money to you, but where it was written, it was in rubles and it was unclear where to send it. I am not a resident of the Russian Federation and live in Kyrgyzstan. I have a master card $. If there is an option to send you money to your card, that would be good. I don’t even know how to do this in rubles. There may be other easier options.

I thought of this because after I purchased broadlink rm2 pro I connected the TV and air conditioning for free, but the rest of our radio stuff is not cheap. There are 19 light switches in the house, 3-4-5 per room, and buying everything is very expensive. Yes, and I would like to change the sockets on the controls, otherwise what kind of smart home would this turn out to be?

In general, my task is to make remote controls with my own hands so that they do not confuse each other and the main thing is that broadlink rm2 pro understands them. At the moment, he does not understand the remote control according to your scheme.

I couldn’t write in the discussion, only registered users write there.

Waiting for your reply.

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 diagram was taken from the website vrtp.ru
Transmitter

Receiver

For work we need a list of parts:
1) PIC16F628A-2 pcs (microcontroller) (link to aliexpress pic16f628a )
2) MRF49XA-2 pcs (radio transmitter) (link to aliexpress MRF 49 XA )
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
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

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

Previously, there was not even close to such an abundance of goods in general and toys in particular. And in many ways, the modern children's paradise owes to progress in electronics. Talking robots, multicopters - all this is not only available in stores, but is sold at a very inexpensive price, for many. In addition, toys are sometimes so advanced in terms of electronic components and interesting in their operation that it’s time to buy them not for children, but for yourself. Especially if the father is a radio amateur :) In general, while accidentally passing by the window of the “Everything for a Dollar” store, I noticed a box with a Chinese radio-controlled car that cost only $10! Naturally, this is for the entire set.

Complete set of R/C machine

• The car is a racing car
• Remote controller remote control
• Four batteries 1.2 V 600 mAh
• Charger 4.8V 250mA

Characteristics of a radio controlled car

• Machine food - 4 pcs. 1.2V nickel-cadmium batteries
• Remote control power - 3 AA batteries AA
• Charging time - 5 hours
• Working time - half an hour
• Radio channel frequency - 27 MHz
• Radio channel range - 10 meters

Everything on the box is written in Chinese - not a single one, let alone Russian - even English word. Well, it's time to learn Chinese or develop intuition :) In theory, there is nothing complicated: put the batteries in the car, three batteries in the remote control - and off we go.

Machine control panel

Please note that the kit does not include batteries for the remote control, only for the car. So you will need 3 AA elements of 1.5 V each.

The remote control immediately attracted attention due to the complete absence of buttons, not counting the power button.

The thing is that here the commands to turn left and right, move forward and backward, are given by tilting. If you open the remote control and examine the board with parts, you can see 4 position sensors. Inside these cylinders, soldered at an angle, there are sensors in the form of balls.

The transmitter chip itself is in DIP format, like the rest of the parts, so the remote control is very compact and lightweight. A 3-arm telescopic antenna is screwed to the front of it. The length when unfolded is about 30 cm. If you are standing next to a car, you don’t have to unfold it. But at a range of more than 5 m, this is necessary.

Radio-controlled car

Before installing the batteries in the battery compartment of the car, you need to charge them. For this purpose, the kit includes a small Charger, naturally impulse.

The board inside is a copy of the usual charger from mobile phone. And the parameters (and circuit) are similar - pulse converter the transistor is about 2-3 watts.

When you turn on the car button (it's on the bottom), all 4 wheels will immediately start flashing with blue and red LEDs installed on the inside. This is both beautiful and convenient - it’s immediately clear that the power is activated. So that there is no situation in which you play around and forget to turn off the power to the car, draining or even destroying the batteries.

Let's take it apart and look under the cover. The receiving part is assembled on the basis of a microcircuit RX-2B. You can switch circuits, they are standard for most 27 MHz, short-range radio-controlled models.

And C945 transistors switch two motors - the main one, which is located in the rear of the car, and the auxiliary one, responsible for turning the front wheels.

The headlights on the front light up when the car is moving forward. At reversing they go out immediately. It’s interesting that they didn’t use LEDs, but light bulbs. This is of course more realistic, but the energy consumption increases by almost 100 mA, so to save money I simply cut the wires coming to them from the control board with scissors.

Video of the machine working

In general, the Chinese Once again They surprise not so much with their technology, although they keep their finger on the pulse and constantly replenish the market with new interesting devices, but with their outrageously low price. Think about how much 4 batteries would cost separately? What about the charger? Not to mention the rest. As for the quality: the child has been playing for more than a month and nothing, the machine is alive and well, although it has already been recharged 20 times.