Documentation

Overview

This is the XL4015 5A buck converter with an integrated 3-digit 7-segment voltmeter built right onto the board. Same 96%-efficient buck topology as the bare XL4015 module, but the onboard display means you can dial in your output voltage at a glance — no multimeter required.

A press of the small S1 button switches the display between input and output voltage, so you can verify both rails on one screen. Wide 4-38V input, 1.25-36V adjustable output, and 5A continuous current capability make this a workhorse for powering Pi clusters, motor controllers, LED arrays, and any project where you want a tunable rail with built-in monitoring.

At a Glance

Specifications

Pinout Diagram

Wiring Guide

Code Examples

The XL4015 is a passive analog regulator — there's no microcontroller-side code. The "code" is the trim potentiometer + display. Examples below show how to monitor the output rail from a microcontroller (useful for closed-loop battery management or undervoltage protection).

Arduino — Monitor Output via ADC

// Monitor XL4015 output rail with Arduino ADC
// Voltage divider: OUT+ -- 30k -- A0 -- 10k -- GND
// Divides up to 22V down to ~5.5V at A0 (Arduino 5V tolerant)

const int sensePin = A0;
const float DIV_RATIO = (30000.0 + 10000.0) / 10000.0;

void setup() { Serial.begin(9600); }

void loop() {
  int raw = analogRead(sensePin);
  float vAtPin = raw * (5.0 / 1023.0);
  float vRail = vAtPin * DIV_RATIO;
  Serial.print("Rail: "); Serial.print(vRail, 2); Serial.println(" V");
  delay(500);
}

ESP32 — Monitor with Internal ADC

// ESP32 - monitor XL4015 output rail
// Same divider, ADC1_CH0 = GPIO 36

const int sensePin = 36;
const float DIV_RATIO = 4.0;
const float VREF = 3.3;

void setup() {
  Serial.begin(115200);
  analogReadResolution(12);  // 0-4095
}

void loop() {
  int raw = analogRead(sensePin);
  float vAtPin = raw * (VREF / 4095.0);
  float vRail = vAtPin * DIV_RATIO;
  Serial.printf("Rail: %.2f V\n", vRail);
  delay(500);
}

Frequently Asked Questions