You will need:
Something to case it all in - whatever takes your fancy! (See step 2 for more information on this part...)
The education bits
I normally run this project with KS3 students (11-14 year olds), as part of an all-round approach to Design Technology, incorporating systems and control with resistant materials. Dependant on age and ability, all students either make simple wooden casings, using box joints, or we do this as part of a sustainability, and use recycled packaging to house the alarm. This instructable only really covers the circuit itself, there'll be more coming on casings soon.
- all to be able to give examples of the applications of simple electronic components
- most should be able to suggest alternative applications for the buzzer and LDR
- some may be able to explain how to reverse the action of the alarm (to become dark activated), and spot trends with the use of components.
- improve skills with soldering
- to be able to suggest interesting and innovative ways of casing the alarm
- to consider the user, and target products appropriately
Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.
Step 1: The Circuit
Using the diagram, solder up your circuit. When looking at the transistor, work with the lettering/flat side towards you.
When soldering, please remember to make sure you are in a well ventiled area, and wearing safety glasses and any other protective equipment you are comfortable with (apron or similar).
Step 2: The Casing
At school, we make our alarms inside wooden casings, and combine it with a wood-joints project. However, other suitable things could be....
- Film canisters
- Chocolate boxes
- Old books
- CD cases
- Jewellery boxes
basically, anything that can be opened and closed (to change the battery), and can have a hole drilled through it to place the LDR. You need to make the spacing for the LDR slightly smaller than the component, so that it can be put on the surface and not fall back through - OR make it an identical size, and then glue it in place.
Participated in the