Paul came to the shop with a 2′ carnival light arrow sign that had five LED light bulbs inside. He asked if I could make them light one at a time to animate the pointing effect. Read on to see how it was done.
Carnival Light Arrow Wiring
The back of the sign was held on with tabs that could be turned, much like a picture frame. Inside the five lights had positive wires in red and ground wires in yellow. The reds were all soldered in a single blob to the positive wire of a 3v battery case (two 1.5 AA batteries). The yellows were also soldered to the negative wire of the battery case. Silly me, not taking a picture before the operation…
First the five positive wires were cut from each other, leaving as much wire as possible. I connected each wire to an Arduino UNO such that the light at the tail end of the arrow was connected to pin 2, the the next to pin 3, and so on.
I also drew in some angles in case you want to try and cut a wooden frame for your own arrow.
Carnival Light Arrow Code
So with each LED connected to a different pin on the Arduino, it was pretty easy to use
digitalWrite() to turn the lights on and off. Here’s the sketch I wrote that includes five different styles of animation.
Carnival Light Arrow Final thoughts
This was a quick & dirty 15 minute fix. The power system in the sign is not enough – 3v is too low to run an Arduino Uno. A 4-8 battery pack would produce about 6-12v, all acceptable to Arduino and enough power to run the lights. To run the lights as-is the simplest way is a 5-12v 1a power supply.
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