I have a 2007 Toyota Sienna that I'm swapping out rims on and want to create a device that acts as a TPMS "sensor" (mimics a sensor) to send information to my cars computer about a given pressure so the TPMS light doesn't blink every time I get in the car. The issue is I don't know where to start! I've read that they use PWM signals (I'm guessing over bluetooth? or is it radio frequencies? idk) and are coded in hex if I'm reading right. I'm also fairly new to programming Arduino's in general, so I don't even know what libraries to include, or how to even code something like that. Any help would be appreciated!
Most people use the CC1101 transceiver to receive or transmit TPMS messages. The search phrase "arduino tpms" will find posts, for example this will receive the data Arduino TPMS Tyre Pressure Display - Hackster.io
Simulating the signal is more difficult and the details vary with manufacturer.
Thanks for the info! I'll definitely look into it 
Hi,
i had a look into this: https://github.com/merbanan/rtl_433/issues/2978
After inspecting rtl_433 i modified the code for my mustang (Ford) and came to that code. That works for my car. Airspy and rtl sdr blog v4 helps a lot. I use arduino nano and EBYTE E07-M1101D-SMA CC1101 433MHz rf Modul Transceiver
Kind regards, Torsten.
#include <ELECHOUSE_CC1101_SRC_DRV.h>
#define CC1101_FREQUENCY 433.92 // Frequency for TPMS
void setup() {
Serial.begin(115200);
Serial.println("Initializing CC1101...");
if (ELECHOUSE_cc1101.getCC1101()){ // Check the CC1101 Spi connection.
Serial.println("Connection OK");
}else{
Serial.println("Connection Error");
}
ELECHOUSE_cc1101.Init(); // must be set to initialize the cc1101!
ELECHOUSE_cc1101.setCCMode(1); // set config for internal transmission mode.
ELECHOUSE_cc1101.setModulation(0); // set modulation mode. 0 = 2-FSK, 1 = GFSK, 2 = ASK/OOK, 3 = 4-FSK, 4 = MSK.
ELECHOUSE_cc1101.setMHZ(CC1101_FREQUENCY); // Here you can set your basic frequency. The lib calculates the frequency automatically (default = 433.92).The cc1101 can: 300-348 MHZ, 387-464MHZ and 779-928MHZ. Read More info from datasheet.
ELECHOUSE_cc1101.setDeviation(47.60); // Set the Frequency deviation in kHz. Value from 1.58 to 380.85. Default is 47.60 kHz.
ELECHOUSE_cc1101.setChannel(0); // Set the Channelnumber from 0 to 255. Default is cahnnel 0.
ELECHOUSE_cc1101.setChsp(199.95); // The channel spacing is multiplied by the channel number CHAN and added to the base frequency in kHz. Value from 25.39 to 405.45. Default is 199.95 kHz.
ELECHOUSE_cc1101.setRxBW(812.50); // Set the Receive Bandwidth in kHz. Value from 58.03 to 812.50. Default is 812.50 kHz.
ELECHOUSE_cc1101.setDRate(20.48); // TH01: wichtig für Erkennung, 20.48 scheint zu laufen; 18.5 Set the Data Rate in kBaud. Value from 0.02 to 1621.83. Default is 99.97 kBaud!
ELECHOUSE_cc1101.setPA(10); // Set TxPower. The following settings are possible depending on the frequency band. (-30 -20 -15 -10 -6 0 5 7 10 11 12) Default is max!
ELECHOUSE_cc1101.setSyncMode(0); // Combined sync-word qualifier mode. 0 = No preamble/sync. 1 = 16 sync word bits detected. 2 = 16/16 sync word bits detected. 3 = 30/32 sync word bits detected. 4 = No preamble/sync, carrier-sense above threshold. 5 = 15/16 + carrier-sense above threshold. 6 = 16/16 + carrier-sense above threshold. 7 = 30/32 + carrier-sense above threshold.
ELECHOUSE_cc1101.setSyncWord(211, 145); // Set sync word. Must be the same for the transmitter and receiver. (Syncword high, Syncword low)
ELECHOUSE_cc1101.setAdrChk(0); // Controls address check configuration of received packages. 0 = No address check. 1 = Address check, no broadcast. 2 = Address check and 0 (0x00) broadcast. 3 = Address check and 0 (0x00) and 255 (0xFF) broadcast.
ELECHOUSE_cc1101.setAddr(0); // Address used for packet filtration. Optional broadcast addresses are 0 (0x00) and 255 (0xFF).
ELECHOUSE_cc1101.setWhiteData(0); // Turn data whitening on / off. 0 = Whitening off. 1 = Whitening on.
ELECHOUSE_cc1101.setPktFormat(0); // Format of RX and TX data. 0 = Normal mode, use FIFOs for RX and TX. 1 = Synchronous serial mode, Data in on GDO0 and data out on either of the GDOx pins. 2 = Random TX mode; sends random data using PN9 generator. Used for test. Works as normal mode, setting 0 (00), in RX. 3 = Asynchronous serial mode, Data in on GDO0 and data out on either of the GDOx pins.
ELECHOUSE_cc1101.setLengthConfig(1); // 0 = Fixed packet length mode. 1 = Variable packet length mode. 2 = Infinite packet length mode. 3 = Reserved
ELECHOUSE_cc1101.setPacketLength(0); // Indicates the packet length when fixed packet length mode is enabled. If variable packet length mode is used, this value indicates the maximum packet length allowed.
ELECHOUSE_cc1101.setCrc(0); // 1 = CRC calculation in TX and CRC check in RX enabled. 0 = CRC disabled for TX and RX.
ELECHOUSE_cc1101.setCRC_AF(0); // Enable automatic flush of RX FIFO when CRC is not OK. This requires that only one packet is in the RXIFIFO and that packet length is limited to the RX FIFO size.
ELECHOUSE_cc1101.setDcFilterOff(0); // Disable digital DC blocking filter before demodulator. Only for data rates ≤ 250 kBaud The recommended IF frequency changes when the DC blocking is disabled. 1 = Disable (current optimized). 0 = Enable (better sensitivity).
ELECHOUSE_cc1101.setManchester(0); // Enables Manchester encoding/decoding. 0 = Disable. 1 = Enable.
ELECHOUSE_cc1101.setFEC(0); // Enable Forward Error Correction (FEC) with interleaving for packet payload (Only supported for fixed packet length mode. 0 = Disable. 1 = Enable.
ELECHOUSE_cc1101.setPRE(0); // Sets the minimum number of preamble bytes to be transmitted. Values: 0 : 2, 1 : 3, 2 : 4, 3 : 6, 4 : 8, 5 : 12, 6 : 16, 7 : 24
ELECHOUSE_cc1101.setPQT(0); // Preamble quality estimator threshold. The preamble quality estimator increases an internal counter by one each time a bit is received that is different from the previous bit, and decreases the counter by 8 each time a bit is received that is the same as the last bit. A threshold of 4∙PQT for this counter is used to gate sync word detection. When PQT=0 a sync word is always accepted.
ELECHOUSE_cc1101.setAppendStatus(0); // When enabled, two status bytes will be appended to the payload of the packet. The status bytes contain RSSI and LQI values, as well as CRC OK.
Serial.println("Tx Mode");
Serial.println("CC1101 initialized.");
}
void generateTPMSData(uint8_t *data, uint32_t id, uint8_t temperature, uint16_t pressure, uint8_t status) {
uint16_t press;
press = (pressure * 61);
data[0] = id & 0xFF;
data[1] = (id >> 8) & 0xFF;
data[2] = (id >> 16) & 0xFF;
data[3] = (id >> 24) & 0xFF;
data[4] = (press) & 0xFF;
data[5] = (temperature+56 ) & 0xFF;
data[6] = (status ) & 0xFF;
data[7] = (data[0] + data[1] +data[2]+data[3]+data[4] + data[5]+data[6]); // TH01: simple checksum
}
void encodeManchester(uint8_t *encoded, const uint8_t *data, size_t len) {
size_t bitIndex = 0;
for (size_t i = 0; i < len; i++) {
for (int bit = 7; bit >= 0; bit--) {
if (data[i] & (1 << bit)) {
// Bit is 1, Manchester encoding is 10
encoded[bitIndex / 8] |= (1 << (7 - (bitIndex % 8)));
bitIndex++;
encoded[bitIndex / 8] &= ~(1 << (7 - (bitIndex % 8)));
} else {
// Bit is 0, Manchester encoding is 01
encoded[bitIndex / 8] &= ~(1 << (7 - (bitIndex % 8)));
bitIndex++;
encoded[bitIndex / 8] |= (1 << (7 - (bitIndex % 8)));
}
bitIndex++;
}
}
}
void loop() {
uint8_t tpmsData[10]; // Actual data
uint8_t encodedData[20]; // Manchester encoded data (2x the size)
// Set preamble: 0xAA, 0xAA, 0xAA, 0xA9 (inverted: 0x55, 0x55, 0x55, 0x56)
tpmsData[0] = 0x00;
tpmsData[1] = 0x01;
// tpmsData[2] = 0xaa;
// tpmsData[3] = 0xa9;
// Generate the TPMS data payload
generateTPMSData(tpmsData + 2 , 0x36145167, 10, 1, 0x4); // Example values
// Encode data using Manchester encoding
memset(encodedData, 0, sizeof(encodedData));
encodeManchester(encodedData, tpmsData, sizeof(tpmsData));
// Print data for debugging
Serial.println("TPMS DATA:");
for (int i = 0; i < sizeof(tpmsData); i++) {
Serial.print(tpmsData[i], HEX);
Serial.print(" ");
}
Serial.println();
// Print data for debugging
Serial.println("ENCODED TPMS DATA:");
for (int i = 0; i < sizeof(encodedData); i++) {
Serial.print(encodedData[i], HEX);
Serial.print(" ");
}
Serial.println();
// Send TPMS data
//ELECHOUSE_cc1101.Sidle();
ELECHOUSE_cc1101.SendData(encodedData, sizeof(encodedData),100);
Serial.println("TPMS signal sent.");
delay(3000); // Wait 2 seconds before sending the next signal
}
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