JavaScript ADC demo.
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js/adc/ai-sensor.js
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js/adc/ai-sensor.js
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// Script created by ChatGPT 4
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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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// Constants for the thermistor calculation
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let B = 3470; // B value of the thermistor
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let R0 = 2000; // Resistance of the thermistor at T0 (in ohms)
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let T0 = 298.15; // Reference temperature (25°C in Kelvin)
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let Vref = 3.3; // Reference voltage in volts
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// Initialize pin A7 as analog
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gpio.init("PA7", "analog", "no");
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// Start analog reading with a reference voltage of 3.3V
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gpio.startAnalog(2048); // vRef = 2.048V (scaled)
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function readTemperature() {
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let millivolts = gpio.readAnalog("PA7");
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// Voltage divider calculation
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let R1 = 2200; // Known resistor value in ohms (2.2kΩ)
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let Vout = millivolts / 1000; // Convert millivolts to volts
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if (Vout === 0) {
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return 0;
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}
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let Rt = R1 * (Vref / Vout - 1); // Corrected thermistor resistance calculation
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// Steinhart-Hart equation to calculate temperature in Kelvin
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let logRt = Math.log(Rt / R0);
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let invT = (1 / T0) + (1 / B) * logRt;
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let tempK = 1 / invT;
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let tempC = tempK - 273.15; // Convert Kelvin to Celsius
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let tempF = tempC * 9 / 5 + 32; // Convert Celsius to Fahrenheit
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return tempF;
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}
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function formatTemperature(temp) {
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let roundedTemp = Math.floor(temp * 100 + 0.5) / 100; // Round to two decimal places
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let intPart = Math.floor(roundedTemp); // Integer part
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let fracPart = Math.floor((roundedTemp - intPart) * 100); // Fractional part
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let intPartStr = to_string(intPart);
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let fracPartStr = fracPart < 10 ? '0' + to_string(fracPart) : to_string(fracPart); // Ensure two digits in the fractional part
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return intPartStr + '.' + fracPartStr;
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}
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// Main loop to read and display the temperature every second
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while (true) {
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let tempF = readTemperature();
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if (tempF !== 0) { // Ignore invalid measurements
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print("Temperature: " + formatTemperature(tempF) + " F"); // Use " F" instead of "°F"
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}
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delay(1000); // Wait for 1 second
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}
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gpio.stopAnalog();
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67
js/adc/sensor.js
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67
js/adc/sensor.js
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// 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();
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