JavaScript ADC demo.

js/adc/ai-sensor.js

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+// Script created by ChatGPT 4
+// @CodeAllNight / MrDerekJamison
+// Discord server - https://discord.com/invite/NsjCvqwPAd
+// Github - https://github.com/jamisonderek/flipper-zero-tutorials
+
+// Flipper Zero JavaScript ADC (Analog-to-Digital Converter) demo.
+
+// Required hardware connections...
+// Step 1. Connect a NTC Thermistor (R0:2K, B:3470K) to 3.3V and Pin A7.
+// Step 2. Connect a 2.2K Resistor to Pin A7 and GND.
+
+// Requires MNTM-005 (or current Momentum dev build)
+
+let gpio = require("gpio");
+let Math = require("math");
+
+// Constants for the thermistor calculation
+let B = 3470; // B value of the thermistor
+let R0 = 2000; // Resistance of the thermistor at T0 (in ohms)
+let T0 = 298.15; // Reference temperature (25°C in Kelvin)
+let Vref = 3.3; // Reference voltage in volts
+
+// Initialize pin A7 as analog
+gpio.init("PA7", "analog", "no");
+
+// Start analog reading with a reference voltage of 3.3V
+gpio.startAnalog(2048); // vRef = 2.048V (scaled)
+
+function readTemperature() {
+    let millivolts = gpio.readAnalog("PA7");
+
+    // Voltage divider calculation
+    let R1 = 2200; // Known resistor value in ohms (2.2kΩ)
+    let Vout = millivolts / 1000; // Convert millivolts to volts
+
+    if (Vout === 0) {
+        return 0;
+    }
+
+    let Rt = R1 * (Vref / Vout - 1); // Corrected thermistor resistance calculation
+
+    // Steinhart-Hart equation to calculate temperature in Kelvin
+    let logRt = Math.log(Rt / R0);
+    let invT = (1 / T0) + (1 / B) * logRt;
+    let tempK = 1 / invT;
+    let tempC = tempK - 273.15; // Convert Kelvin to Celsius
+    let tempF = tempC * 9 / 5 + 32; // Convert Celsius to Fahrenheit
+
+    return tempF;
+}
+
+function formatTemperature(temp) {
+    let roundedTemp = Math.floor(temp * 100 + 0.5) / 100; // Round to two decimal places
+    let intPart = Math.floor(roundedTemp); // Integer part
+    let fracPart = Math.floor((roundedTemp - intPart) * 100); // Fractional part
+
+    let intPartStr = to_string(intPart);
+    let fracPartStr = fracPart < 10 ? '0' + to_string(fracPart) : to_string(fracPart); // Ensure two digits in the fractional part
+
+    return intPartStr + '.' + fracPartStr;
+}
+
+// Main loop to read and display the temperature every second
+while (true) {
+    let tempF = readTemperature();
+    if (tempF !== 0) { // Ignore invalid measurements
+        print("Temperature: " + formatTemperature(tempF) + " F"); // Use " F" instead of "°F"
+    }
+    delay(1000); // Wait for 1 second
+}
+
+gpio.stopAnalog();

js/adc/sensor.js

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