Teaching robotics with low-cost kits

Robotics does not need a big budget

Robotics for schools often sounds expensive, with trolleys of kits and a dedicated room. In practice, students can learn the main ideas, which are sensing, deciding and acting, with very simple materials. A cell, a small motor and a toothbrush make a moving robot. A cardboard frame, a few syringes and some water make a hydraulic arm. Once students are confident, an Arduino board and a handful of sensors open the door to programmable robots, and a class set can be built up gradually.

This article describes a path from zero cost to low cost, with ideas for lessons, groups, safety and assessment.

The three big ideas

Whatever the kit, keep three ideas in front of the class. A robot senses the world, using a switch, a light sensor or a distance sensor. It decides, using a circuit or a program. And it acts, using a motor, a light or a buzzer. Each project in the path below strengthens one or more of these ideas. Ask students to name the sense, decide and act parts of every model.

A four-stage path

1. Stage 1, motion without electronics: balloon-powered cars and hydraulic arms show force, pressure and motion, with no battery required.
2. Stage 2, simple electric robots: the bristlebot and circuit boards use a cell and a motor to introduce circuits, switches and vibration.
3. Stage 3, sensors and decisions: light-seeking or line-following models, with simple sensors and a small controller.
4. Stage 4, programmable robots: Arduino-based obstacle avoiders and line followers, where students write code and tune sensors.

Lesson ideas

• Bristlebot race: build, test and improve, then discuss why the design changes affected the speed (one period).
• Hydraulic arm: build with syringes and discuss pressure in liquids (two to three periods).
• Circuit board: series and parallel circuits with switches and bulbs (two to three periods).
• Human robot game: one student acts as the robot and follows instructions written by a partner, to introduce algorithms and debugging (one period).
• Line follower with Arduino: wire a sensor, read values, set a threshold and write the loop (four to six periods).

Managing budget and equipment

Buy in small sets, and share. One kit per group of four is enough. Label boxes, keep a parts list and ask a student to check it after each lesson. Choose widely available parts such as common motors, standard sensors and the common Arduino boards, so that replacements are easy to find. Keep spare wires, cells and a multimeter. Many schools begin with the cheapest stage and add equipment as results show. The sensors guide, the motors and drivers book and the Arduino starter projects ebook on this site are free and list the parts used in typical builds.

Group work

Set groups of three or four with rotating roles: builder, programmer, tester and recorder. Every student should take each role in turn, so that no one becomes the group's permanent typist or tool holder. Ask groups to keep a short log of design, tests and changes. A short team review at the end of each session, with two stars and a wish, builds a habit of reflection.

Safety

• Use low-voltage cells and USB power only. No mains-powered builds by students.
• Soldering, hot glue and cutting hard materials are teacher tasks, or closely supervised for older students.
• Check polarity before connecting a battery, and remove batteries when a model is not in use.
• Tie back long hair near motors and wheels. Do not let robots run off tables.
• Dispose of cells properly and do not mix old and new cells.
• Watch for hot motors and drivers, and never leave a charging battery unattended.

Assessment

Assess the thinking, not only the winning. Use a rubric with criteria such as: explains the sensing, deciding and acting parts; tests and improves the design; works safely and shares tasks; records results clearly; and presents the work. A race result can be part of the fun, but it should not be the main mark. For programming, look at whether code is commented, whether the student can explain each part and whether they can fix a deliberate bug.

Going further

For schools that want a full programme, our robotics for schools page describes workshops and programmes that run inside school. For self-study and clubs, the free ebooks on robotics for young kids, Arduino starter projects, line follower and obstacle avoiding robots give step-by-step builds. Link robotics to the maths and science in class: ratios in gears, speed and distance, circuits and energy.