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210 | extern volatile uint16_t accNoisePeak[2]; |
210 | extern volatile uint16_t accNoisePeak[2]; |
Line 211... | Line 211... | ||
211 | 211 | ||
212 | /* |
212 | /* |
213 | * Air pressure. |
213 | * Air pressure. |
214 | * The sensor has a sensitivity of 45 mV/kPa. |
214 | * The sensor has a sensitivity of 45 mV/kPa. |
- | 215 | * An approximate p(h) formula is = p(h[m])[kPa] = p_0 - 11.95 * 10^-3 * h |
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- | 216 | * p(h[m])[kPa] = 101.3 - 11.95 * 10^-3 * h |
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- | 217 | * 11.95 * 10^-3 * h = 101.3 - p[kPa] |
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215 | * An approximate p(h) formula is = p(h[m])[Pa] = p_0 - 11.95 * 10^-3 * h |
218 | * h = (101.3 - p[kPa])/0.01195 |
216 | * That is: dV = 45 mV * 11.95 * 10^-3 dh = 0.53775 mV / m. |
219 | * That is: dV = -45 mV * 11.95 * 10^-3 dh = -0.53775 mV / m. |
- | 220 | * That is, with 38.02 * 1.024 / 3 steps per mV: -7 steps / m |
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- | 221 | ||
- | 222 | Display pressures |
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- | 223 | 4165 mV-->1084.7 |
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- | 224 | 4090 mV-->1602.4 517.7 |
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- | 225 | 3877 mV-->3107.8 1503.4 |
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- | 226 | ||
- | 227 | 4165 mV-->1419.1 |
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- | 228 | 3503 mV-->208.1 |
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- | 229 | Diff.: 1211.0 |
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- | 230 | ||
- | 231 | Calculated Vout = 5V(.009P-0.095) --> 5V .009P = Vout + 5V 0.095 --> P = (Vout + 5V 0.095)/(5V 0.009) |
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- | 232 | 4165 mV = 5V(0.009P-0.095) P = 103.11 kPa h = -151.4m |
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- | 233 | 4090 mV = 5V(0.009P-0.095) P = 101.44 kPa h = -11.7m 139.7m |
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- | 234 | 3877 mV = 5V(0.009P-0.095) P = 96.7 kPa h = 385m 396.7m |
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- | 235 | ||
- | 236 | 4165 mV = 5V(0.009P-0.095) P = 103.11 kPa h = -151.4m |
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- | 237 | 3503 mV = 5V(0.009P-0.095) P = 88.4 kPa h = 384m Diff: 1079.5m |
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- | 238 | Pressure at sea level: 101.3 kPa. voltage: 5V * (0.009P-0.095) = 4.0835V |
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217 | * That is, with 1.024 / 3 steps per mV: 0.183552 steps / m |
239 | This is OCR2 = 143.15 at 1.5V in --> simple pressure = |
- | 240 | */ |
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218 | */ |
241 | |
219 | #define AIRPRESSURE_SUMMATION_FACTOR 54 |
242 | #define AIRPRESSURE_SUMMATION_FACTOR 14 |
220 | #define AIRPRESSURE_FILTER 8 |
243 | #define AIRPRESSURE_FILTER 8 |
221 | // Minimum A/D value before a range change is performed. |
244 | // Minimum A/D value before a range change is performed. |
222 | #define MIN_RAWPRESSURE (200 * 2) |
245 | #define MIN_RAWPRESSURE (200 * 2) |
223 | // Maximum A/D value before a range change is performed. |
246 | // Maximum A/D value before a range change is performed. |
Line 227... | Line 250... | ||
227 | #define MAX_RANGES_EXTRAPOLATION 240 |
250 | #define MAX_RANGES_EXTRAPOLATION 240 |
Line 228... | Line 251... | ||
228 | 251 | ||
229 | #define PRESSURE_EXTRAPOLATION_COEFF 25L |
252 | #define PRESSURE_EXTRAPOLATION_COEFF 25L |
Line -... | Line 253... | ||
- | 253 | #define AUTORANGE_WAIT_FACTOR 1 |
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- | 254 | ||
230 | #define AUTORANGE_WAIT_FACTOR 1 |
255 | #define ABS_ALTITUDE_OFFSET 108205 |
231 | 256 | ||
232 | extern volatile uint16_t simpleAirPressure; |
257 | extern volatile uint16_t simpleAirPressure; |
233 | /* |
258 | /* |
234 | * At saturation, the filteredAirPressure may actually be (simulated) negative. |
259 | * At saturation, the filteredAirPressure may actually be (simulated) negative. |