I'm working on a really simple project teaching kids to code with the Arduino Uno (gotta be better than learning Office, right?!). They've built a basic fade app and would like to make a "magic egg" - a blown egg over an LED to diffuse the light, and a hidden battery pack in a "nest" of paper.
Should be easy, I said. (first mistake!)
However, I've bought a 6 x AA batteries holder (which can make 7.2 V rechargeable battery pack from NiMH / NiCd cells or 9V battery pack from alkaline cells, apparently),filled it with duracell AA's and plugged it in to the power jack (which steps down the power, right?) - no LED light. It doesn't fry the LED, just doesn't go.
Having replaced the batteries a few times, can I conclude that the cheapy ebay adaptor (second mistake!) here -http://www.ebay.co.uk/itm/140941895155?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
doesn't work, or is there a step I'm missing?
Many thanks for your help,