For education of boys and girls, 10 - 15? years, I need som very small working projects. It should end up with somthing usefullfor those childs.
I have one, but think it is to complicatet for the target group:
RJ45 cable tester:
4 signals out trough pair 1 and 2, returning trough a plug and bak to 4 blinking leds on the print.
A project sould only a few kind of instructiones, 10 - 16 in all.
Let the smal solutione ve a challenge :-)
HM
mneary The cable tester can be done in 9 kinds of instructions, 15 instructions total.
I'd be tempted to make an educational project a little more open ended and kid friendly than just a cable tester. You will have some some kids who will do exactly as they are instructed and end up with the finished project, but others will want to experiment and expand your design once they've done it.
I would at least add a pushbutton, which opens all sorts of possibilities. For example, in addition to testing cables it could then test reflexes (flash an LED, wait for pushbutton, light LED if it's better than previous time, etc.). You could easily pick apps where debouncing is not an issue.
I would think that while the programming exercise and hardware aspects would be interesting, most 10 to 15 year olds have never given a moment's thought to the concept of cables needing testing. Beating their friends in a reflex race, on the other hand, might grab their attention.
Gwen 
That is actually a great choice for a simple project :)
I'd also put a button and 2 wires coming out with alligator clips on the end.... hook the clips to a wire or whatever and push the button. If there is continuity have the LEDs come on ... if no continuity then blink them wildly :) In fact just making the continuity tester would be a nice simple project and leave out the cable connectors.
Basically just 2 or 3 AA batteries, an ATtiny, a button, some LEDs, and a small plastic box.
I'd use Blue, Red, Green and Orange LEDs to make it prettier :)
Thanks for feedback. I will remember rours addvices. Though, I feel that that projeckt are a bit complicatet as the very first one.
HM
