diff options
| -rw-r--r-- | dive.h | 15 | ||||
| -rw-r--r-- | uemis.c | 28 |
2 files changed, 22 insertions, 21 deletions
@@ -298,6 +298,21 @@ static inline int depth_to_mbar(int depth, struct dive *dive) return depth / 10.0 * specific_weight + surface_pressure + 0.5; } +/* for the inverse calculation we use just the relative pressure + * (that's the one that some dive computers like the Uemis Zurich + * provide - for the other models that do this libdivecomputer has to + * take care of this, but the Uemis we support natively */ +static inline int rel_mbar_to_depth(int mbar, struct dive *dive) +{ + int cm; + double specific_weight = 1.03 * 0.981; + if (dive->salinity) + specific_weight = dive->salinity / 10000.0 * 0.981; + /* whole mbar gives us cm precision */ + cm = mbar / specific_weight + 0.5; + return cm * 10; +} + #define SURFACE_THRESHOLD 750 /* somewhat arbitrary: only below 75cm is it really diving */ /* this is a global spot for a temporary dive structure that we use to @@ -75,25 +75,6 @@ void decode( uint8_t *inbuf, uint8_t *outbuf, int inbuf_len ) { /* end code from Bob Trower */ /* - * pressure_to_depth: In centibar. And when converting to - * depth, I'm just going to always use saltwater, because I - * think "true depth" is just stupid. From a diving standpoint, - * "true depth" is pretty much completely pointless, unless - * you're doing some kind of underwater surveying work. - * - * So I give water depths in "pressure depth", always assuming - * salt water. So one atmosphere per 10m. - */ -static int pressure_to_depth(uint16_t value) -{ - double atm, cm; - - atm = bar_to_atm(value / 100.0); - cm = 100 * atm + 0.5; - return (cm > 0) ? 10 * (long)cm : 0; -} - -/* * convert the base64 data blog */ int uemis_convert_base64(char *base64, uint8_t **data) { @@ -212,7 +193,12 @@ void uemis_parse_divelog_binary(char *base64, void *datap) { datalen = uemis_convert_base64(base64, &data); dive->airtemp.mkelvin = *(uint16_t *)(data + 45) * 100 + 273150; - dive->surface_pressure.mbar = *(uint16_t *)(data +43); + dive->surface_pressure.mbar = *(uint16_t *)(data + 43); + if (*(uint8_t *)(data + 19)) + dive->salinity = 10300; /* avg grams per 10l sea water */ + else + dive->salinity = 10000; /* grams per 10l fresh water */ + /* dive template in use: 0 = air 1 = nitrox (B) @@ -253,7 +239,7 @@ void uemis_parse_divelog_binary(char *base64, void *datap) { sample = prepare_sample(divep); dive = *divep; /* prepare_sample might realloc the dive */ sample->time.seconds = u_sample->dive_time; - sample->depth.mm = pressure_to_depth(u_sample->water_pressure); + sample->depth.mm = rel_mbar_to_depth(u_sample->water_pressure, dive); sample->temperature.mkelvin = (u_sample->dive_temperature * 100) + 273150; sample->cylinderindex = u_sample->active_tank; sample->cylinderpressure.mbar = |