MicroPython YS-RF34T 433MHz ASK/OOK UART Transceiver

MicroPython examples using YS-RF34T 433MHz ASK/OOK UART transceivers.

This module consists of an unlabelled MCU that provides a UART interface to two daughter ASK/OOK modules.

A 433MHz receiver (YS-RF470) and a 433MHz transmitter (H34C).

This module can be used to emulate or program a ASK/OOK based fixed code remotes.

Does not support rolling code.

Examples

from machine import Pin, UART
uart = UART(1, tx=14, rx=15, baudrate=9600)

# sniff for a remote
def sniff():
    while True:
        if uart.any():
            print(uart.readline())

# eg. received b'\xfd\x84\x19\x04D\xdf'

# replay a remote
def replay():
    # almost the same buf as received
    # byte 1 is how long to tx for
    uart.write(bytearray(b'\xfd\x03\x84\x19\x04D\xdf'))

# transmit
def tx(addr, key, time=3, width=64):
	buf = bytearray(b'\xfd\x00\x00\x00\x00\x00\xdf')
	buf[1] = time & 0xff
	buf[2] = (addr >> 8) & 0xff
	buf[3] = addr & 0xff
	buf[4] = width & 0xff
	uart.write(buf)

# (0x84 << 8) | 0x19 = 33817
tx(33817, 4)

# receive
def rx():
    while True:
        if uart.any():
            buf = uart.readline()
            if len(buf) == 6 and buf[0] == 0xfd and buf[5] == 0xdf:
                addr = (buf[1] << 8) | buf[2]
                key = buf[3]
                print('Found! Address: {}, Key: {}'.format(addr,key))

rx()
# Found! Address: 33817, Key: 1
# Found! Address: 33817, Key: 2
# Found! Address: 33817, Key: 4
# Found! Address: 33817, Key: 8

The MCU understands 2262, 2260, 1527 encoded transmissions.

If you're not receiving anything, check your RX and TX are not switched otherwise the remote might be using an unsupported protocol.

Pinout

Pin	Name	Description
1	GND	Ground
2	RXD	UART receive
3	TXD	UART transmit
4	VCC	Supply voltage 3V3 - 5V

Connections

TinyPICO ESP32

from machine import Pin, UART
uart = UART(1, tx=14, rx=15, baudrate=9600)

YS-RF34T	TinyPICO (ESP32)
GND	GND
RXD	14 TXD
TXD	15 RXD
VCC	3V3

Transmit Protocol

Write 7 bytes and the MCU will build and send out the desired packet using the onboard ASK/OOK RF module.

Packet = (Header, Time, Address 2, Address 1, Key, Width, Footer), eg.

byte	name	description
0	header	constant value of 0xFD
1	time	transmit time - signal repeats until timeout
2	addr2	high address bits
3	addr1	low address bits
4	key	which button was pressed
5	width	width of signal in ms
6	footer	constant value of 0xDF

header	time	addr2	addr1	key	width	footer	eg
0xFD	0x03	0x84	0x19	0x04	0x40	0xDF	b'\xfd\x03\x84\x19\x04\x40\xdf'
0xFD	0x06	0x22	0x33	0x44	0x50	0xDF	b'\xfd\x06\x22\x33\x44\x50\xdf'

Receive Protocol

When the MCU receives a signal from the receiving ASK/OOK RF module, it will output 6 bytes over UART.

The packet is almost identical to the TX packet, only is missing the Time value.

byte	name	description
0	header	constant value of 0xFD
1	addr2	high address bits
2	addr1	low address bits
3	key	which button was pressed
4	width	width of signal in ms
5	footer	constant value of 0xDF

header	addr2	addr1	key	width	footer	eg
0xFD	0x84	0x19	0x04	0x44	0xDF	b'\xfd\x84\x19\x04\x44\xdf'

RTL-SDR capture with URH and replay with YS-RF34T

See RTL-SDR-URH.md.

Parts

• YS-RF34T $5.85 AUD
• TinyPICO $20.00 USD
• RTL-SDR $21.95 AUD

Links

• micropython.org
• TinyPICO Getting Started
• URH
• RTL-SDR

License

Licensed under the MIT License.

Copyright (c) 2019 Mike Causer