Servo Angle Dial Kit

Classes 7-8, typical ages 12–14. Age ranges vary by learner. Guided low-voltage electronics.

Activity engagement

60–90 minutes. Explore 10–15 min · Build 20–30 min · Test and discuss 30–45 min. Estimated time for building, testing and discussion.

What you need

A computer with a USB port and Arduino IDE is required and is not included.

Included components

• Small Breadboard / Mini Solderless Board - 400 points — 1 breadboard
• Jumper Wire Combo - Male to Male, Male to Female and Female to Female Breadboard Connecting Wires (10 Qty Each) — 1 set
• Illustrated Activity Guide and Observation Sheets — 1 set
• Fitted Headers and Labelled Connection Leads — 1 set
• Arduino Uno R3 CH340G version compatible Arduino Development Board — 1 controller board
• USB A to B Programming Cable for Arduino Uno/ Arduino Mega — 1 data cable
• Tower Pro SG90 Servo Motor - 9 gms Mini/Micro Servo Motor — 1 servo
• 10 K POTENTIOMETER — 1 potentiometer
• Enclosed Regulated 5 V Servo Supply with Fitted Lead — 1 power supply

What you learn

• A potentiometer supplies an analog input.
• An input range can be mapped to an output range.
• A servo needs a suitable power supply separate from its signal pin.

Connection guide

• Pot outer pins → Uno 5 V/GND; wiper → A0. Servo signal → D9.
• Servo red/+ → separate supplied 5 V supply; brown/black → its GND. Join that GND to Uno GND.
• Do not join the external supply +5 V rail to the USB-powered Uno 5 V rail.

Steps to make it

1. Disconnect all power and identify the supplied part labels and pinouts before wiring.
2. Leave the servo horn unloaded and connect the two power domains exactly as shown.
3. Upload the sketch before enabling the external servo supply.
4. Turn the dial slowly from end to end; compare angles near 0%, 50% and 100% input.
5. Stop if the servo strains or hits a mechanical limit; the sketch restricts commands to 10–170 degrees.
6. Change only the named parameter for the extension, repeat the controlled trials, save observations and disconnect power afterward.

Programming resources

Arduino IDE: select Arduino Uno and the USB port. Use the supplied USB data cable. Serial Monitor/Plotter: 115200 baud.

Libraries to install

• Servo (Arduino)

Download starter sketch

Test challenge

Compare five knob positions with the commanded angles printed in Serial Monitor.

Observation task

Analog reading, mapped angle and observed horn position.

Expected result

The unloaded servo follows the dial within its practical mechanical limits.

If it does not work

Jitter or resets often indicate inadequate servo power or a missing shared ground. Never power the servo from a GPIO.

Try next

Restrict travel to 45–135 degrees and explain the mapping change.

Use and supervision

Use only the supplied low-voltage DC parts. Disconnect power before rewiring; check polarity and labelled pinouts. No soldering or exposed mains connections. Adult guidance is recommended.

How this experiment works

Download class activity guide

Cover illustrations show component types. Functional animations explain principles and are not recorded prototype tests. Follow the supplied connection labels and pinouts.