ELECTRONIC PROJECTS
TEACHING RESOURCES
HELP
FLASHING ALIEN PROJECT - YEAR 7
Project concept by Phil Townshend c.

UPDATED:.18:10 27 April 2008
This project is ideal for Key Stage 3 Electronics. It covers shaping resistant materials, PCB production and soldering electronic components. There are downloads and presentations to help delivery and takes around 16-18 hours.

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

Download Powerpoint Slideshow of Aliens.
Circuit Diagram
NOTES ABOUT THIS CIRCUIT
This is a common but very reliable and robust astable circuit. The timing resistors are the two 47K ones. This gives a flash rate of about 1Hz. Substituting these for other values will change the flash rate. I have used 22K and 10K being about as fast as is useful.

DOWNLOADS TO ASSIST TEACHING:

TRANSISTOR TYPES

The two transistors can be almost any type with at least 100mA Ic capability.
I have used the following dependent on price.

  • TO92a style: BC183/4L, 2N3704
  • TO92c style: BC183/4, BC337, BC547/8/9

RESOURCE MATERIAL
TO92a version
E C B
 The following files are formatted for the TO92A case type transistor.
Types such as BC184L and 2N3704

COMPONENT ASSEMBLY
Step-by-step instructions on assembling the PCB in a PowerPoint presentation.
CIRCUIT & PCB DETAILS
Details of circuit, component values and component placement
PCB TRACK LAYOUTS

Simulteaneous flash
Alternate flash

These files have 20 PCB layouts with text boxes for students to add their names. There are also labels for component polarity and guides for holes to secure the PCB and the leads.
TEACHING & RESOURCE MATERIAL
TO92c version
C B E
 The following files are formatted for the TO92C case type transistor.
Types such as BC337 and BC547

COMPONENT ASSEMBLY
Step-by-step instructions on assembling the PCB in a PowerPoint presentation.
CIRCUIT & PCB DETAILS
Details of circuit, component values and component placement
PCB TRACK LAYOUTS

Simulteaneous flash
Alternate flash

These files have 20 PCB layouts with text boxes for students to add their names. There are also labels for component polarity and guides for holes to secure the PCB and the leads.

PCB & kit of parts available		 HINTS:

A 'U' shaped piece of wood housed the battery and also secured the PCB into place. A piece of plastic was placed between the PCB and the battery to prevent it shorting out the track.

To use just one LED, short together the other LED terminals.

A common mistake is LED and transistor orientation.
EDUTEK LTD.
22 STROUD LANE,
BOURNEMOUTH.
DORSET, BH23 3QU
Tel./Fax: 01202 474720
Tel: +447976 515290

Contact us by email.
www.edutek.ltd.uk - Working Electronics For Students & Teachers