Catch Santa Project


Task: To design a form of alarm to catch intruders (Santa)
Difficulty: Beginner – Advanced

For this project you will need:

  • A Crumble;
  • A battery pack with batteries (not rechargeable);
  • Croc-leads
  • A selection of Crumbs (components).

You will also possibly need craft materials, including scissors, paper, glue, card and colours.

The main aim of this task is to create and code a device which will’catch Santa’ – much like a burglar alarm. The device needs to be triggered somehow by Santa, which will then in turn trigger an audible and/or visual alert.

Here are a few ideas to get you started:


Door Alarm

We have used a reed switch and a magnet on a door to create this alarm. Every time the door is opened, the magnet moves away from the reed switch causing the buzzer to beep (motor output – notice the light).

This is how the alarm is connected. The + and – on the buzzer are connected to the corresponding motor one pads, and the switch has one side connected to a + output, and the other to C (input).

As you can see, the code is relatively simple. When the switch is open (magnet moved away) the buzzer will beep once. It will continuously beep whilst the magnet isn’t nearby.

Pressure Pad

We have used some card, tinfoil and a few coffee stirrers to create a pressure pad style switch. When the pad is pressed down, the large LED flashes.

This is how the pad is connected. The + and – of the LED are attached to the corresponding motor pads, and one end of the switch is connected to a + output, and the other to an input (A, B ,C or D) on the Crumble.

This is how we made the switch. We gently curved three coffee stirrers, and used some foil to conduct the electricity. When the foil-covered stirrer is pressed down, it completes the flow of electricity.

The code to get our pressure pad working is very similar to the code for the door alarm. Instead, the light will flash when the Crumble input becomes HI.

Ultrasonic Trip Wire

We have used the ultrasonic distance sensor as a type of ‘trip wire’. When the beam is broken, the Sparkle baton flashes red for a set number of times.

This is how everything is connected. The Baton is connected to the corresponding +, – and D pads, and the ultrasonic distance sensor is connected to the corresponding + and – on the battery pack, and then the trigger (T) is connected to B, and echo (E) is connected to A.

In this program, we set a variable (called Distance) to the distance value given by the ultrasonic distance sensor. If the distance is less than 110cm or in essence, the beam is broken, the Sparkle Baton will flash on and off 10 times.


We would love to see how you plan to catch Santa!