Momentum-Apps/protocols/oregon2.c

/* Oregon remote termometers. Usually 443.92 Mhz OOK.
 *
 * The protocol is described here:
 * https://wmrx00.sourceforge.net/Arduino/OregonScientific-RF-Protocols.pdf
 * This implementation is not very complete. */

#include "../app.h"

static bool decode(uint8_t *bits, uint32_t numbytes, uint32_t numbits, ProtoViewMsgInfo *info) {
    if (numbits < 32) return false;
    const char *sync_pattern = "01100110" "01100110" "10010110" "10010110";
    uint64_t off = bitmap_seek_bits(bits,numbytes,0,numbits,sync_pattern);
    if (off == BITMAP_SEEK_NOT_FOUND) return false;
    FURI_LOG_E(TAG, "Oregon2 preamble+sync found");

    info->start_off = off;
    off += 32; /* Skip preamble. */

    uint8_t buffer[8], raw[8] = {0};
    uint32_t decoded =
        convert_from_line_code(buffer,sizeof(buffer),bits,numbytes,off,"1001","0110");
    FURI_LOG_E(TAG, "Oregon2 decoded bits: %lu", decoded);

    if (decoded < 11*4) return false; /* Minimum len to extract some data. */
    info->pulses_count = (off+11*4*4) - info->start_off;

    char temp[3] = {0}, deviceid[2] = {0}, hum[2] = {0};
    for (int j = 0; j < 64; j += 4) {
        uint8_t nib[1];
        nib[0] = (bitmap_get(buffer,8,j+0) |
                  bitmap_get(buffer,8,j+1) << 1 |
                  bitmap_get(buffer,8,j+2) << 2 |
                  bitmap_get(buffer,8,j+3) << 3);
        if (DEBUG_MSG) FURI_LOG_E(TAG, "Not inverted nibble[%d]: %x", j/4, (unsigned int)nib[0]);
        raw[j/8] |= nib[0] << (4-(j%4));
        switch(j/4) {
        case 1: deviceid[0] |= nib[0]; break;
        case 0: deviceid[0] |= nib[0] << 4; break;
        case 3: deviceid[1] |= nib[0]; break;
        case 2: deviceid[1] |= nib[0] << 4; break;
        case 10: temp[0] = nib[0]; break;
        /* Fixme: take the temperature sign from nibble 11. */
        case 9: temp[1] = nib[0]; break;
        case 8: temp[2] = nib[0]; break;
        case 13: hum[0] = nib[0]; break;
        case 12: hum[1] = nib[0]; break;
        }
    }

    float tempval = ((temp[0]-'0')*10) +
                     (temp[1]-'0') +
                    ((float)(temp[2]-'0')*0.1);
    int humval = (hum[0]-'0')*10 + (hum[1]-'0');

    fieldset_add_bytes(info->fields,"Sensor ID",deviceid,4);
    fieldset_add_float(info->fields,"Temperature",tempval,1);
    fieldset_add_uint(info->fields,"Humidity",humval,7);
    return true;
}

ProtoViewDecoder Oregon2Decoder = {
    .name = "Oregon2",
    .decode = decode,
    .get_fields = NULL,
    .build_message = NULL
};