Documentation

Overview

The RC Servo Tester (also sold as the CCPM Consistency Master) is a small standalone tool that generates the standard RC servo signal — a 50 Hz PWM pulse train — without needing a receiver, flight controller, or any code. Plug in a servo, feed it 4.8–6 V, and turn the knob: the servo follows. It is the fastest way to answer the eternal bench questions: is this servo alive, how far does it travel, and does it center properly?

Three output columns carry the same signal simultaneously, which is where the “CCPM consistency” name comes from: helicopter swashplates driven by three servos need all three to respond identically, and driving them side by side instantly exposes a slow or off-center unit. The three modes cover the practical cases — Manual puts the pulse width on the knob, Neutral locks the output at the 1.5 ms center point for installing servo horns, and Auto sweeps back and forth continuously for endurance and smoothness checks.

It also doubles as an ESC tester: an electronic speed controller reads the same signal as a servo, so the tester works as a stand-in throttle for bench-testing and calibrating ESCs. This manual covers the pinout, the wiring for servos, multi-servo comparison, and ESCs, the three modes, and microcontroller sketches that measure or reproduce what the tester does.

At a Glance

Specifications

Pinout Diagram

The left header is the OUT side: three identical columns (1–3), each with rows S (signal), + (power), and − (ground) — a servo plug slides straight onto a column. The right 3-pin column is the power input, marked 4.8–6 V, with the same S / + / − ordering. The knob drives Manual mode, the select button cycles modes, and the three LEDs show which mode is active.

Wiring Guide

Code Examples

Arduino — Measure the Tester’s Pulse Width

// Tester OUT column S pin -> D2, tester GND -> Arduino GND
const int PULSE_PIN = 2;

void setup() {
  Serial.begin(9600);
  pinMode(PULSE_PIN, INPUT);
}

void loop() {
  // Width of the HIGH pulse in microseconds (typ. 800-2200)
  unsigned long us = pulseIn(PULSE_PIN, HIGH, 100000);
  if (us > 0) {
    Serial.print("Pulse: ");
    Serial.print(us);
    Serial.println(" us");
  } else {
    Serial.println("No signal");
  }
  delay(200);
}

Arduino — Build Your Own “Man Mode”

#include <Servo.h>

// Servo signal -> D9, potentiometer wiper -> A0
Servo servo;

void setup() {
  servo.attach(9, 800, 2200);   // match the tester's range
}

void loop() {
  int raw = analogRead(A0);               // 0-1023
  int us = map(raw, 0, 1023, 800, 2200);  // knob -> pulse width
  servo.writeMicroseconds(us);
  delay(15);
}

ESP32 — Auto-Sweep Equivalent

// Library Manager: install "ESP32Servo"
#include <ESP32Servo.h>

Servo servo;

void setup() {
  servo.setPeriodHertz(50);
  servo.attach(18, 800, 2200);   // signal on GPIO 18
}

void loop() {
  for (int us = 800; us <= 2200; us += 10) {
    servo.writeMicroseconds(us);
    delay(10);
  }
  for (int us = 2200; us >= 800; us -= 10) {
    servo.writeMicroseconds(us);
    delay(10);
  }
}

Raspberry Pi Pico — MicroPython Servo Driver

from machine import Pin, PWM
import time

# Servo signal -> GP15, servo power from 5V (VBUS), common GND
pwm = PWM(Pin(15))
pwm.freq(50)

def write_us(us):
    # 50 Hz frame = 20000 us; duty_u16 is 0-65535
    pwm.duty_u16(int(us * 65535 / 20000))

while True:
    write_us(1500)      # neutral
    time.sleep(1)
    for us in range(800, 2201, 10):   # sweep up
        write_us(us)
        time.sleep(0.01)
    for us in range(2200, 799, -10):  # sweep down
        write_us(us)
        time.sleep(0.01)

Frequently Asked Questions

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