RX-3 Low Cost RF Receiver Modules

Radio Module RX-3 The smallest remote control in the world with the largest usability

The board RX-3 contains electronics which process the output from the receiver and 433 MHz receiver module which comes assembled, aligned and redy to work Complete radio receiver module with Keeloq rollingcode decoder. Maximum of 4 channels, 6 remotes, mode: mono, bistable, low battery, channel signaling, last state of memory. Works only with all Corado remotes. Range of remotes tested to 80 m in field of vision. Pre-built and aligned transmitter and receiver modules FeaturesComplete Super Programmable Receiver Module Minimal external requirements and easy adaptation to own needs Low-cost Solution, High Integration Level Supply Voltage 5V accurancy 5% Iin=4mA. Programmable Microprocessor Microchip PIC12F629 ( PIC12F675 with built-in ADC with 10-bit resolution and internal EEPROM is offered as an option) Size board: w 20 mm, h 16 mm 10 pins with 2mm spacing for vertical or horizontal installation, enabling connection to other PCBs

5 pads to reprogram the microprocessor using ICSP without removing the RX-3 module from the main board Operating Temperature Range -30C to70C. Frequency 366MHz or 433 Mhz. Transmittion rate max. 5KHz with ASK modulation Receiver RX-3 learns up to 6 remotes Corado with HCS200; HCS300; HCS301on the board transmitter.

PIN DESCRIPTION
1 - Antenna 22 cm for frequency 366 MHz or 17 cm for 433,92 MHz.
2 - RSSI Receive Signal Strength Indicator, I max 1 mA.
3 - Gp3 Input receiver (application Microchip number DS41190A pdf microcontroller PIC12F629)
digital power supply from 0 to 5 V if transmission on. When transmission off the input Gps3 is in low stage.
The Gp3 may be connected to the next processor or another devices which uses serial transmitter information
4 - Gp4 Input to configuration and adding transmters and output to sygnalisation on/off channel or low battery.
5 - Gp5 Output from 4th channel to control buffer for example ULN2003.
6 - VCC Power supply 5V+ -0,2/0,2.
7 - Gp2 Output 3rd channel to control buffer for example ULN2003.
8 - Gp1 Output 2nd channel to control buffer for example ULN2003..
9 - Gp0 Output 1st channel to control buffer for example ULN2003.
10 - VSS Ground .

Najmniejszy sterownik radiowy na swiecie z największym zastosowaniem

The smallest remote control in the world with the largest usability

Code Hopping or Rolling Code. The advantage of a rolling code (code hopping) system is changing anyway. To gues the code combination, you"re going to need 23 bilion years. It makes very secure system. For all intents and purposes, it is immpossible to electronically "crack".
Microchip invented a system called KeeLoq - better know to you and me as a rolling code. What this does simply present a different code every time the transmitter button is pressed. The really clever part is that the receiver "learns" the algoritm which controls the code so it knows what code to expect. Once learnt, the receiver is effectively "locked" to that transmitter. Actually, it's even clever than that, because the transmitted code is, for all intents and purposes, random. The receiver can still work out what the code is going to be in advance. If it gets the right code, it actuates. If not - you're out.
The chances of the same code being transmitted twice in a person's lifetime is possible at four transmissions per day, every day, it's reckoned to be about 44 years.
Heart of this system is a Microchip proprietary IC, the HCS301. It combines a 32-bit hopping code generated by a nonlinear encryption algoritm with a 28-bit serian number and six information bits to create a 66-bit code word. The code word length eliminates the thread of code scanning and the code-hopping mechanism makes each transmission unique, rendering code, capture and resend techniques useless.

Even if it didn't code-hop, 66 bits allows 7.3 x 10 19 combinations, which according to Microchip would only take 230.000.000.000 years to scan.
The chip itself is olso protected against intrusion. Several important data are stored in an EEPROM array whicz is not accessible via any external connection. These include the crypt key, a unique and secret 64-bit number used to encryp and decrypt data, the serial number and configuration data. The EEPROM data is programmable but read-protected. It can be verified only after an automaticerase and programming operation, protecting against attemts to gain access to keys or to manipulate synchronisation values.
The code is changed every time a button is pressed on the transmitter.
If the button is pressed 10 times while out of range of the receiver, no problem. But if it is pressed more than 16 times synchronisation between the two is lost. However, it only takes two presses of butto in range to restore synchronisation. A complete code will take 100 ms to send (it could be as low as 25ms). But if you manage to hit the button and relase it before 100 ms (difficult but possible) , it will keep sending that complete code. If you hold down the button, it will keep sending that same code. And if you press another button while the firs is held down, it will abort the firs and send the second.

KeeLoq is a very robust system. It's not absolutely foolproof - nothing is (if they steal your transmitter)

For most users, it gives almost total peace-of-mind. That's why the system has been adpted by so many vehicle antry/exit and alarm system manufacturers. Access controllers and so on. And that why the system used in the RX-3