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0084d92239
The ntc_temp2 lookup table was declared as 'char', which can be unsigned on some platforms, causing negative temperature values (-30°C to -1°C) to be incorrectly interpreted. Changed to int8_t to ensure proper signed integer handling of negative temperatures. Fixes #1389 Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
104 lines
3.9 KiB
C++
104 lines
3.9 KiB
C++
#include "t1000e_sensors.h"
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#include <Arduino.h>
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#define HEATER_NTC_BX 4250 // thermistor coefficient B
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#define HEATER_NTC_RP 8250 // ohm, series resistance to thermistor
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#define HEATER_NTC_KA 273.15 // 25 Celsius at Kelvin
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#define NTC_REF_VCC 3300 // mV, max voltage of 3V3 sensor rail
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#define LIGHT_REF_VCC 2400 //
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static unsigned int ntc_res2[136] = {
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113347, 107565, 102116, 96978, 92132, 87559, 83242, 79166, 75316, 71677, 68237, 64991, 61919, 59011,
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56258, 53650, 51178, 48835, 46613, 44506, 42506, 40600, 38791, 37073, 35442, 33892, 32420, 31020,
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29689, 28423, 27219, 26076, 24988, 23951, 22963, 22021, 21123, 20267, 19450, 18670, 17926, 17214,
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16534, 15886, 15266, 14674, 14108, 13566, 13049, 12554, 12081, 11628, 11195, 10780, 10382, 10000,
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9634, 9284, 8947, 8624, 8315, 8018, 7734, 7461, 7199, 6948, 6707, 6475, 6253, 6039,
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5834, 5636, 5445, 5262, 5086, 4917, 4754, 4597, 4446, 4301, 4161, 4026, 3896, 3771,
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3651, 3535, 3423, 3315, 3211, 3111, 3014, 2922, 2834, 2748, 2666, 2586, 2509, 2435,
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2364, 2294, 2228, 2163, 2100, 2040, 1981, 1925, 1870, 1817, 1766, 1716, 1669, 1622,
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1578, 1535, 1493, 1452, 1413, 1375, 1338, 1303, 1268, 1234, 1202, 1170, 1139, 1110,
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1081, 1053, 1026, 999, 974, 949, 925, 902, 880, 858,
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};
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static int8_t ntc_temp2[136] = {
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-30, -29, -28, -27, -26, -25, -24, -23, -22, -21, -20, -19, -18, -17, -16, -15, -14, -13, -12, -11,
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-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
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10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
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30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
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50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,
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70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,
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90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105,
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};
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static float get_heater_temperature(unsigned int vcc_volt, unsigned int ntc_volt) {
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int i = 0;
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float Vout = 0, Rt = 0, temp = 0;
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Vout = ntc_volt;
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Rt = (HEATER_NTC_RP * vcc_volt) / Vout - HEATER_NTC_RP;
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for (i = 0; i < 136; i++) {
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if (Rt >= ntc_res2[i]) {
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break;
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}
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}
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temp = ntc_temp2[i - 1] + 1 * (ntc_res2[i - 1] - Rt) / (float)(ntc_res2[i - 1] - ntc_res2[i]);
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temp = (temp * 100 + 5) / 100;
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return temp;
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}
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static int get_light_lv(unsigned int light_volt) {
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float Vout = 0, Vin = 0, Rt = 0, temp = 0;
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unsigned int light_level = 0;
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// Seeed's firmware maps the photocell reading to a 0-100 % range rather than lux.
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if (light_volt <= 80) {
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light_level = 0;
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return light_level;
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} else if (light_volt >= 2480) {
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light_level = 100;
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return light_level;
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}
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Vout = light_volt;
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light_level = 100 * (Vout - 80) / LIGHT_REF_VCC;
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return light_level;
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}
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float t1000e_get_temperature(void) {
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unsigned int ntc_v, vcc_v;
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digitalWrite(PIN_3V3_EN, HIGH);
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digitalWrite(SENSOR_EN, HIGH);
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analogReference(AR_INTERNAL_3_0);
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analogReadResolution(12);
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delay(10);
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unsigned int rail_v = (1000.0 * (analogRead(BATTERY_PIN) * ADC_MULTIPLIER * AREF_VOLTAGE)) / 4096;
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vcc_v = (rail_v > NTC_REF_VCC) ? NTC_REF_VCC : rail_v;
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ntc_v = (1000.0 * AREF_VOLTAGE * analogRead(TEMP_SENSOR)) / 4096;
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digitalWrite(PIN_3V3_EN, LOW);
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digitalWrite(SENSOR_EN, LOW);
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return get_heater_temperature(vcc_v, ntc_v);
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}
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uint32_t t1000e_get_light(void) {
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int lux = 0;
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unsigned int lux_v = 0;
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digitalWrite(PIN_3V3_EN, HIGH);
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digitalWrite(SENSOR_EN, HIGH);
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analogReference(AR_INTERNAL_3_0);
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analogReadResolution(12);
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delay(10);
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lux_v = 1000 * analogRead(LUX_SENSOR) * AREF_VOLTAGE / 4096;
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lux = get_light_lv(lux_v);
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digitalWrite(SENSOR_EN, LOW);
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digitalWrite(PIN_3V3_EN, LOW);
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return lux;
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}
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