27 weeks? No problem.
A couple of weeks for basic electronic measurement.
A session on "Aggregating existing technology into a new format" Give examples, and let the students brainstorm.
One suggestion is building a Jambox for their MP3 players.
1. Used 12V UPS battery, Obtain locally from a IT shop as they "Clean house"
2. A mid sized plastic tool or tackle box with a removable internal shelf. If the students are advanced enough, get many different sizes and let their creativity go.
3. A pair of speakers, look at Partsexpress.com for very low cost, or hit up the local car stereo shops and ask for donations.
3. A low cost car amplifier, This will be the most expensive item, and may prove difficult to locate them in a large number on the cheap. (But I did..) An alternative is the PWB from a set of computer speakers. You can also harvest the speakers
4. A switch to power on \ off the amp.
5. 1\8 phono to RCA cable.
6. If the MP3 player the students provide use a replaceable battery (A very good idea) include a 12v to 1.5v LM317 reg and 2 resistors and a cap for noise. Fabricate a dummy "Battery" and provide the power to the MP3 player VIA the LM317.
7. If the MP3 player is USB, a LM78M05 12 to 5v, and a scrap USB cable obtained from the local electronics "treasure bin" (Mind the alley. This would power the MP3 player.
Assemble. Stand back and be amazed.
I can assure you, every child that builds one of these will be the envy of their peers, AND these boxes will not be discarded.
Once excited, and engaged your class will not fail. You may spark the development of an engineer or two.
