Home > Group Projects > Flashing Alien Project
Project concept by Phil Townshend - copyright 1996.

UPDATED:.21:56 05 March 2020

A 8-10 week project that is ideal for Key Stage 2 or 3 D&T.

It incorporates a astable circuit that flashes 1 or 2 LEDs. These can be of any colour and used to add effect to an Alien model made from MDF or plywood.

Many skills are covered in this project and it has been a favourite with students and running for years.

The theme is Aliens which gives a broad spectrum for some inventive ideas.

This project is available as kits in our shop.


The circuit can be used for a model on any theme but Aliens gives students a wide spectrum to draw ideas from.

The LEDs can be used for eyes (most common), antennae, nose, ends of tentacles, horns etc. Students are encouraged to add features made from pipe cleaners, coiled solid insulated copper wire and any other bits and pieces you can find.

The model is based on 150x100mm piece of 6mm MDF. Extra features are cut from 3mm MDF and attached to form a "relief" effect

The LEDs can be connected directly to the PCB or extended on rainbow wire to reach further.

The PCB and plastic insulator are screwed into the battery holder making a neat unit which is glued to the rear of the model. Only 2 screws are needed.

The battery holder is made from 18mm chipwood which is just the right size to fit a PP3, 9v battery.


  • Battery holder - 18mm chipboard
  • 6mm MDF 150x100mm,
  • 3mm MDF offcuts
  • PCB & Components
  • Rainbow wire
  • PVA Glue
  • 12mm x 3mm self tapping screws
  • Wirecutters and Screwdriver
  • Soldering iron, stand and wire
  • Drill, 5mm bit, 2.5mm bit
  • Plastic insulator for battery/PCB
The circuit is a well known dual transistor astable and can be altered in a few ways to personalise the operation.
  • Any LED colour can be used
    - 3mm or 5mm types of any colour
  • LEDs can flash together or alternately
    - there are 2 versions of the PCB that can be used.
  • The speed of the flashing can be altered
    - by changing the value of R1 and R2 (from 10K to 22K or 47K), helps to understand basic component function.

Circuit Diagram

The speed of the flash is altered by changing R1 and R2. Reasonable values range from 10K for fast flash (about 4Hz) to about 47K.

The transistors can be any TO92c type, such as BC183, BC547. Look up the NPN transistor table for various common types.

To prevent wires breaking off from repeated movement, drill 3mm holes in the PCB to feed the wires through to take the strain.

Previous work

A pack with a comprehensive guide through the project with detailed lesson plans and assessment covering NC PoS and PLTs, will be available within the next few days.

Topics of Learning include:

  • Identifying and reading electronic components
  • Soldering Components
  • Cutting and shaping resistant materials
  • Designing and planning processes
  • Experimenting and modelling

Click here for more details

This project is available as kits in our shop.
Step-by-step instructions on assembling the PCB in a PowerPoint presentation.
Useful compact cards that have a reduced version of the chart above.
A Powerpoint presentation of a range of Alien examples from different TV shows, films and comic books.
A chart for working out the 3 band resistor colour coding system.
If you have a copy of LiveWire then this is a step-by-step guide on using it and producing the astable circuit.
Details of circuit, component values and component
A working simulation of the astable circuit used in this project using LiveWire software.