Every time I do a quiz card workshop, somebody always asks for red LED's. Usually, we use green LED's. That way, when you are playing the game and pick the right answer, the green light goes on. I like this version. It's easy and fun to change the "right" answer to trick the people you're playing with. But when I run the workshop, there are always a few kids who ask for red LED's, too. They want the green light to go on when the answer is correct, but they also want a red LED to go on when the answer is wrong. Usually I bring a couple of red LED's and leave them as a challenge. The last time I visited the Rainbow Eggheads , I did promise to send them a picture of a quiz card circuit with a red and a green LED. They're a savvy group - I'll post it here instead.
We had worked with the green-light quiz card in the winter session of the Inventors' Workshop and quite a few of them had asked me about adding red LED's. One of the biggest challenges with the quiz cards is knotting the conductive thread through the hole in the tabbed battery. Wrapping the thread around the paper fasteners is easy, but connecting it to the battery is hard. I thought it was time to try out some of the conductive foil tapes. So I used a roll of aluminum conductive foil tape and some red LED's from Newark Electronics/ element 14 .
The tape was fun to work with. But everything has it's own challenges! We had to make sure there was always a good connection between the tape and the component, so we wrapped the tape around the paper fasteners and battery terminals. It was easy to stick down the LED legs with the tape. One of our inventors came up with a new way to fasten the LED to the card and we all liked it so much we started using it.
So now we know how to make Quiz Cards with both red and green LED's. I do like the green LED circuit, it's easier to put together when you're learning. I think what I'll do is modify my Quiz Card circuit so that it is easier to see how to add the red LED's in. I'll continue to start the workshops with the green LED's, and once that's working, I'll leave the red LED's as a challenge. It's always easier to get things working one step at a time!