While at the IPCE-EPEC conference in Prague I went to a workshop run by one of the organisers, Leos Dvorak. With a little introduction we got down to business making charge detectors. These have appeared in a Phys Ed paper and are really neat little devices and cost pennies.
We could also make a number of other little gizmos, Leos had all the gear ready to go. I made the charge detector first and then made a little polarity determining device. It’s a really good workshop because you can see the potential for introducing people to soldering. You use wood and brass nails to make a framework which you can wrap wire onto and then you solder on to that.
You can be really heavy handed with the soldering, an ideal way to introduce people to it. Leos is on the middle in the picture below, wearing the light blue shirt.
So after the conference and on my way to the airport I went looking for a present for the gorgeous Sandra. I was after something in the clothing department so I went into ladies clothes shops. And I went into a lot of them. Initially I went into smaller ones, but couldn’t find what I wanted. So then I went into bigger shops. These have alarms at the entrance to stop people stealing things. When the first one went off I didn’t pay much attention and carried on walking. By the time the third one went off I was getting a bit curious but carried on walking anyway. By the time the fifth one went off I thought it was just a matter of time before I got stopped and was getting nervous. So it was in H&M. The alarm went off and the security guard stopped me. He was very good about it and clearly didn’t think I’d got anything, but he didn’t speak English. Anyway, I was getting curious about what was setting the alarm off and thought it must be computer gear in my hand luggage. I gave him the bag and sent him through the alarm – nothing. I went through with my hold luggage – off it went. I took off my rucksack and went through – nothing. I gave him my rucksack and sent him through – off it went. So now I have to undo my bag and take out my dirty laundry. I come to a bag of presents that includes the charge detector and a Star Wars toy for James. He sees this and says “Star Wars” as if that was the item causing the problem. But I knew that had no tag and was made entirely of plastic. So I take out the charge detector and walk through…”beep, beep, beep….”.
I think the alarm must use a changing magnetic field that energised the detector and then amplified the signal which in course altered the field and caused the alarm to go off. I’m looking forward to taking it on my next shopping trip!