--- /dev/null
+/* Maverick ET-73x BBQ Sensor
+ *
+ * Copyright © 2016 gismo2004
+ * Credits to all users of mentioned forum below!
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+*/
+
+/**The thermometer transmits 4 identical messages every 12 seconds at 433.92 MHz,
+ * using on-off keying and 2000bps Manchester encoding,
+ * with each message preceded by 8 carrier pulses 230uS wide and 5ms apart.
+ *
+ * Each message consists of 26 nibbles (104 bits total),
+ * which can each only have the value of 0x5, 0x6, 0x9, or 0xA.
+ * For nibble 24 some devices are sending 0x1 or 0x2
+ *
+ * Assuming MSB first and falling edge = 1.
+ *
+ * quarternary conversion of message needed:
+ * 0x05 = 0
+ * 0x06 = 1
+ * 0x09 = 2
+ * 0x0A = 3
+ *
+ * Message looks like this:
+ * a = Header (0xAA9995)
+ * b = device state (2=default; 7=init)
+ * c = temp1 (need to substract 532)
+ * d = temp2 (need to substract 532)
+ * e = checksum (the checksum gets renewed on a device reset, and represents a kind of session_id)
+ *
+ * nibble: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
+ * msg: a a a a a a b b c c c c c d d d d d e e e e e e e e
+ *
+ * further information can be found here: https://forums.adafruit.com/viewtopic.php?f=8&t=25414
+**/
+
+
+#include "rtl_433.h"
+#include "util.h"
+
+#define MAV_MESSAGE_LENGTH 104
+#define TEMPERATURE_START_POSITION_S1 8
+#define TEMPERATURE_START_POSITION_S2 13
+#define TEMPERATURE_NIBBLE_COUNT 5
+
+
+//here we extract bitbuffer values, for easy data handling
+static void convert_bitbuffer(bitbuffer_t *bitbuffer, unsigned int *msg_converted, char *msg_hex_combined) {
+ //quarternary convertion
+ unsigned int quart_convert[16] ={0,0,0,0,0,0,1,0,0,2,3,0,0,0,0,0};
+ int i;
+ for(i = 0; i < 13; i++) {
+ char temp[2];
+ sprintf(temp, "%02x", bitbuffer->bb[0][i]);
+ msg_hex_combined[i*2] = temp[0];
+ msg_hex_combined[i*2+1] = temp[1];
+
+ msg_converted[i*2] = quart_convert[bitbuffer->bb[0][i] >> 4];
+ msg_converted[i*2+1] = quart_convert[bitbuffer->bb[0][i] & 0xF];
+ }
+
+ msg_hex_combined[26]='\0';
+ if(debug_output) {
+ fprintf(stderr, "final hex string: %s\n",msg_hex_combined);
+ fprintf(stderr, "final converted message: ");
+ for(i = 0; i <= 25; i++) fprintf(stderr, "%d",msg_converted[i]);
+ fprintf(stderr, "\n");
+ }
+}
+
+static float get_temperature(unsigned int *msg_converted, unsigned int temp_start_index){
+ //default offset
+ float temp_c = -532.0;
+ int i;
+
+ for(i=0; i < TEMPERATURE_NIBBLE_COUNT; i++) {
+ temp_c += msg_converted[temp_start_index+i] * (1<<(2*(4-i)));
+ }
+
+ return temp_c;
+}
+
+
+//changes when thermometer reset button is pushed or powered on.
+static char* get_status(unsigned int *msg_converted) {
+ int stat = 0;
+ char* retval = "unknown";
+
+ //nibble 6 - 7 used for status
+ stat += msg_converted[6] * (1<<(2*(1)));
+ stat += msg_converted[7] * (1<<(2*(0)));
+
+ if(stat == 2)
+ retval = "default";
+
+ if(stat == 7)
+ retval = "init";
+
+ if(debug_output)
+ fprintf(stderr, "device status: \"%s\" (%d)\n", retval, stat);
+
+ return retval;
+}
+
+
+static uint32_t checksum_data(unsigned int *msg_converted) {
+ int32_t checksum = 0;
+ int i;
+
+ //nibble 6 - 17 used for checksum
+ for(i=0; i<=11; i++) {
+ checksum |= msg_converted[6+i] << (22 - 2*i);
+ }
+
+ if(debug_output)
+ fprintf(stderr, "checksum data = %x\n", checksum);
+
+ return checksum;
+}
+
+
+static uint32_t checksum_received(unsigned int *msg_converted, char *msg_hex_combined) {
+ uint32_t checksum = 0;
+ int i;
+
+ //nibble 18 - 25 checksum info from device
+ for(i=0; i<=7; i++) {
+ checksum |= msg_converted[18+i] << (14 - 2*i);
+ }
+
+ if(msg_hex_combined[24]=='1' || msg_hex_combined[24]=='2') {
+ checksum |= (msg_converted[25]&1) << 3;
+ checksum |= (msg_converted[25]&2) << 1;
+
+ if(msg_hex_combined[24]=='2')
+ checksum |= 0x02;
+ }
+ else {
+ checksum |= msg_converted[24] << 2;
+ checksum |= msg_converted[25];
+ }
+
+ if(debug_output)
+ fprintf(stderr, "checksum received= %x\n", checksum);
+
+ return checksum;
+}
+
+static uint16_t shiftreg(uint16_t currentValue) {
+ uint8_t msb = (currentValue >> 15) & 1;
+ currentValue <<= 1;
+
+ // Toggle pattern for feedback bits
+ // Toggle, if MSB is 1
+ if (msb == 1)
+ currentValue ^= 0x1021;
+
+ return currentValue;
+}
+
+static uint16_t calculate_checksum(uint32_t data) {
+ //initial value of linear feedback shift register
+ uint16_t mask = 0x3331;
+ uint16_t csum = 0x0;
+ int i;
+ for(i = 0; i < 24; ++i) {
+ //data bit at current position is "1"
+ //do XOR with mask
+ if((data >> i) & 0x01)
+ csum ^= mask;
+
+ mask = shiftreg(mask);
+ }
+ return csum;
+}
+
+static int maverick_et73x_callback(bitbuffer_t *bitbuffer) {
+ data_t *data;
+ char time_str[LOCAL_TIME_BUFLEN];
+ int32_t session_id;
+ char msg_hex_combined[27];
+ unsigned int msg_converted[26];
+
+ //we need an inverted bitbuffer
+ bitbuffer_invert(bitbuffer);
+
+ if(bitbuffer->num_rows != 1)
+ return 0;
+
+ //check correct data length
+ if(bitbuffer->bits_per_row[0] != MAV_MESSAGE_LENGTH)
+ return 0;
+
+ //check for correct header (0xAA9995)
+ if((bitbuffer->bb[0][0] != 0xAA || bitbuffer->bb[0][0] != 0xaa ) || bitbuffer->bb[0][1] != 0x99 || bitbuffer->bb[0][2] != 0x95)
+ return 0;
+
+ //convert hex values into quardinary values
+ convert_bitbuffer(bitbuffer, msg_converted, msg_hex_combined);
+
+ //checksum is used to represent a session. This means, we get a new session_id if a reset or battery exchange is done.
+ session_id = (calculate_checksum(checksum_data(msg_converted)) & 0xffff) ^ checksum_received(msg_converted, msg_hex_combined);
+
+ if(debug_output)
+ fprintf(stderr, "checksum xor: %x\n", session_id);
+
+ local_time_str(0, time_str);
+
+ data = data_make("time", "", DATA_STRING, time_str,
+ "brand", "", DATA_STRING, "Maverick",
+ "model", "", DATA_STRING, "ET-732/ET-733",
+ "id", "Session_ID", DATA_INT, session_id,
+ "status", "Status", DATA_STRING, get_status(msg_converted),
+ "temperature_C1", "TemperatureSensor1", DATA_FORMAT, "%.02f C", DATA_DOUBLE, get_temperature(msg_converted,TEMPERATURE_START_POSITION_S1),
+ "temperature_C2", "TemperatureSensor2", DATA_FORMAT, "%.02f C", DATA_DOUBLE, get_temperature(msg_converted,TEMPERATURE_START_POSITION_S2),
+ "crc", "", DATA_STRING, "ok",
+ NULL);
+ data_acquired_handler(data);
+
+ return bitbuffer->num_rows;
+}
+
+static char *output_fields[] = {
+ "time",
+ "brand"
+ "model"
+ "id"
+ "status",
+ "temperature_C1",
+ "temperature_C2",
+ "crc",
+ NULL
+};
+
+
+r_device maverick_et73x = {
+ .name = "Maverick ET-732/733 BBQ Sensor",
+ .modulation = OOK_PULSE_MANCHESTER_ZEROBIT,
+ .short_limit = 230,
+ .long_limit = 0, //not used
+ .reset_limit = 4000,
+ .json_callback = &maverick_et73x_callback,
+ .disabled = 0,
+ .demod_arg = 0,
+ .fields = output_fields
+};
projects / rtl-433.git / blobdiff