Hi,
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? … 1497.l2649 doesn’t work, or is there a step I’m missing?
Many thanks for your help,
Marie
It should be easy enough to make sure that all the connections in the battery holder are good. But, I don’t see any reason why the LED shouldn’t light if all the connections are good.
First thing I’d do is make sure the Arduino is still alive. Plug the USB cable into it and see if the power LED comes on and a sketch of your choosing still runs. Next see if there’s voltage present at the barrel plug and that it’s the correct polarity. If you have a DMM, measure the voltage from inner to outer conductor. It should be positive and >7v. If you don’t have a DMM, go buy one. :mrgreen: OTOH is you’re placing LEDs in eggs then you should have a 220 - 470 ohm resistor handy and an LED. You can check the presence and polarity of the voltage using them.
IIRC the Arduino barrel jack is center positive and there is a reverse voltage protection diode in that circuit path. No voltage (obviously) or reverse voltage will keep the power LED on the Arduino off.