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  • Author Author: garengllc
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Christmas Spirit Meter

garengllc

I like to make homemade Christmas props for the front yard.  I have a handful of props I put out by the sidewalk to make things interactive and this year I thought that I would try something new, The Christmas Spirit-tron (the spelling on the last word is up for debate and I would love to get some thoughts).  Basically you spin a crank to light some bulbs.  The faster you spin, the more lights you light up.  I was basically shooting for something like the strong-man sledge hammer games at the fair when you try to ring the bell.  I had a couple of things I was shooting for with this project that I thought would be fun.  I was thinking it would be nice to make this one a little more educational, I was planning on writing something up to help people understand what was going on (which I of course haven't done yet, but maybe this will help get me moving image), I tried to recycle/reuse as much as I could for this, and lastly I wanted to show how hard it can be to create enough power to light up a few light bulbs.

 

I have a video I am working on, and I hope to write some more up soon.  I am part way done with a schematic, but it is a pretty small BOM, so it should be pretty easy to follow once I finally do it.  So far the kids seem to enjoy it, and it gets many spins a night.

 

Happy Christmas all.

  • And here is the first run-through of it:

  • Well, I hoped to do a better video, but it is out in the yard and I don't want to tear it apart while it is working well image .  One comment I would like to make is that in the video I said that I was generating 5V for the LM3914, I am actually running that off of 15V as well.  So both converters put out 15V, it is just that one has better current output.  I am still working on a schematic, but as you can see in the video, it isn't too complicated.  There is 2 lights per bulb for the first 4, and 3 lights for the top bulb.  When you add it all up, you get ~30W, and that was about what I was measuring when I had some meters hooked up to it (it was actually closer to 25W at "full speed").

     

    I had planned on putting some nice analog meters on the box to show people how much voltage and current they were producing, but I also wanted to show the wattage.  So I bought a self powered back-lit panel meter that show current, voltage, wattage, and Ahr rating (which is pretty useless for this app).  It worked pretty well, but took about 2s to fire up before you would start to get readings.  After I built the enclosure (which was PVC trim board left over from my deck install, you can see some scraps in the back), I couldn't come up with a slick way to mount the panel meter and make it waterproof.  My wife talked me out of stressing over it so I could get it into the yard and come back to it later, good advice from her as usual.  I am glad that I didn't attach it to the enclosure because when people are cranking, there is a lot of wiggle to the whole thing, this would make it very hard to read.  In a video I am going to post later of the first run of it in the yard, you can see A LOT of wiggling.  I ended up adding two 5ft poles banged into the ground behind it and mounted them to the enclosure, it is a lot better now.  I think if I do end up putting one/all/some of the meters out, it would be better to mount them separate on something that won't be wiggling.

     

    Let's see how well this walk-through embeds: