67 lines
2.2 KiB
JavaScript
67 lines
2.2 KiB
JavaScript
// Script created in video https://youtu.be/ETn9E4L6EY0
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// @CodeAllNight / MrDerekJamison
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// Discord server - https://discord.com/invite/NsjCvqwPAd
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// Github - https://github.com/jamisonderek/flipper-zero-tutorials
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// Flipper Zero JavaScript ADC (Analog-to-Digital Converter) demo.
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// Required hardware connections...
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// Step 1. Connect a NTC Thermistor (R0:2K, B:3470K) to 3.3V and Pin A7.
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// Step 2. Connect a 2.2K Resistor to Pin A7 and GND.
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// Requires MNTM-005 (or current Momentum dev build)
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let gpio = require("gpio");
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let Math = require("math");
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gpio.init("PA7", "analog", "no");
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// 2048mV reference voltage
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gpio.startAnalog(2048);
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function mvToSensorResistance(millivolts) {
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let Rfixed = 2200; // 2200 ohm fixed resistor
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let Vtotal = 3.3; // resistor + sensor series connected to 3.3
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let Vrfixed = millivolts / 1000; // millivolts to volts
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let I = Vrfixed / Rfixed;
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let Rtotal = Vtotal / I;
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let Rsensor = Rtotal - Rfixed;
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return Rsensor;
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}
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function resistanceToCelsius(rsensor) {
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// B value of the thermistor
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let B = 3470;
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// Reference temp (25°C in Kelvin)
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let T0 = 273.15 + 25;
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// Resistance of the thermistor at T0 (in ohms)
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let R0 = 2000;
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// B or β parameter equation
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// from https://en.wikipedia.org/wiki/Thermistor
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let invT = (1 / T0) + (1 / B) * Math.log(rsensor/R0);
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let tempK = 1 / invT;
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// Convert Kelvin to Celsius
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let tempC = tempK - 273.15;
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return tempC;
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}
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// Function to print 1 digits after decimal written by ChatGPT 4o.
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function formatTemperature(temp) {
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let roundedTemp = Math.floor(temp * 10 + 0.5) / 10; // Round to one decimal place
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let intPart = Math.floor(roundedTemp); // Integer part
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let fracPart = Math.floor((roundedTemp - intPart) * 10); // Fractional part
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return to_string(intPart) + '.' + to_string(fracPart);
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}
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for (let i=0; i<50; i++) {
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let mv = gpio.readAnalog("PA7");
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let sensor_resistance = mvToSensorResistance(mv);
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let tempC = resistanceToCelsius(sensor_resistance);
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let msg = to_string(mv) + " mV:";
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msg = msg + to_string(sensor_resistance) + " Ohms:";
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msg = msg + formatTemperature(tempC) + " C";
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print(msg);
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delay(1000); // 1 second
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}
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gpio.stopAnalog(); |