In the latest episode of Sylvia’s Mini Maker Show, she’s at it again with this classic MiniPOV build and persistence of vision demonstration.
Today we’ll be building the awesome MiniPOV kit by Adafruit, available in the Maker Shed. It’s your own little persistence of vision display in the palm of your hand. Lets go!
For this build we’ll need:
- Mini POV kit
- Soldering iron
- Rosin core solder
- A multimeter (good for checking continuity)
- A USB to serial adapter (if you don’t have a serial port on your computer)
- A vice or helper hands (not required, but really handy!)
- Flush wire cutters
The MiniPOV is a great build for beginners because of the low part count and simple assembly. It comes complete build instructions and lots more!
First things first, get yourself a clear workspace with plenty of light, and start soldering in the parts according to the build instructions. Make sure to bend the leads a little after putting it in so that it won’t slide out when you flip the board over, and once each component is soldered in, be sure to wear some eye protection and clip those leads as flush as possible.
When it’s time to do the serial connector, make sure to put lots of solder on its leads, as the connector sticks out like a handle and these connections are the only thing holding it to the board! Also try to make sure and only connect the serial cable by holding the metal of the connector, not the board itself!
For your little ATTiny chip, its legs are bowed out a bit, so there’s a trick to getting it into the socket: first make sure you’re free of static charge (touch some grounded metal, computer case, door handle or maybe your little brother or sister) then on a nice flat surface, carefully bend all the pins in a little till they look about parallel. Then match up the notch on the chip to the notch on the socket, and push it in.
For the battery wires, I highly recommend putting a blob of hot glue where they meet the board so they don’t break off from moving it around. (This happened to us twice!) Once your wires are in and your batteries are loaded, flip the switch and you should see blinkies!
Now setup the AVR loader software for your operating system according to the guide. Once you’ve got it up and running, it’s time to make something new for the POV to display.
My dad hacked together a cool little web app for making messages or graphics that outputs a binary array you can paste directly into the code. Once you’ve hacked your 1s and 0s, it’s time to compile and upload! This can all be a bit tricky to get right, but once you get the hang of it, you’ll be AVR programming like a pro.
When the upload finishes, you can start experimenting! Try attaching your MiniPOV to a bicycle wheel and give it a spin. Maybe try some long exposure photos, moving it around in different fun shapes or patterns while the shutter is open, or attach it to a spinning toy you can twirl around and amaze your friends with!
So, how does this all work anyways? It’s easy!
Imagine a single slice of your list of 1s and 0s, made into holes and dots respectively on a strip of paper (which by the way, used to be how binary information was stored!) If you shine a light through it, you can see that the 1s allow the light through, while the 0s remain dark. By then quickly switching to the next slice of the picture over time, we’re only missing one last piece of the puzzle. To get the whole picture, all we have to do is move the slice to the next position in space at the right time sequentially, and our brains do the rest of the work by piecing the whole picture together from the afterimages! That’s persistence of vision! Aren’t brains great?! No wonder zombies are after them!
There’s lots more you can do with it as well, like change out the red LEDs for another color like blue, green or red, attach a sensor to switch the scroll direction, or change the firmware and make it into a strobe or anything else you can dream up. because it’s a micro controller you can make it do almost anything!
That’s it for this episode, remember to experiment with your own designs, respect your soldering iron and get out there and MAKE something!
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