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Persistence of Vision (POV) Wands are a fun way to create interesting long exposure photographs and light displays.  The wand consists of a single row of LEDs controlled by an Arduino Uno.  When the wand is turned on it appears to be flickering in a random pattern, but if you move it quickly back and forth, you will see text or an image appear.  This wand project is incredibly customizable, I've included all CAD files, firmware, build documentation, and schematics.  Feel free to choose your own color LEDs, write personalized messages, and maybe even add something new to the project!



Parts list:

(1x) Arduino Uno REV 3 Radioshack #276-128
(20x) Amber Super-bright LED Indicator Radioshack #55050630
(1x) Arduino Proto Shield Radioshack #276-140
(1x) 9V Alkaline Battery Radioshack #23-866
(1x) Heavy-Duty 9V Snap Connectors Radioshack #270-324
(20x) 1/4 watt resistors (sample calculation below)

      from the specs of the LEDs I used:
      "Continuous forward current: 25mA"
      "Forward voltage: 3V"

      using the following relationship:
      V(volts) = I(amps) * R(ohms)
      rearranged to:
      R = V / I

      we can calculate the resistance as follows:
      voltage across resistor = 5V - 3V = 2V
      2V / 0.025A = 80ohms

      I used 100 ohm resistors so that the LEDs wouldn't be operating at their maximum ratings.  Check the datasheet of the LEDs you use to calculate these values.

I've attaching a fritzing document with a breadboard and schematic view of the circuit (and included them above) for reference.

Step 1: Build a Support for Your Wand

The first thing you'll want to do is make a mount for your project.  I laser cut a piece of acrylic into a wand shape, but you could use a piece of plywood, cardboard, or plastic.  I've attached the adobe illustrator and eps files of the wand and correct hole 0.1" hole spacing for the LEDs and resistors; even if you don't have a laser cutter, these files still might be useful to print out as a template.  Drill out the holes with a drill and a small drill bit.  The rectangular holes at the bottom of the wand will be used for mounting a 9 volt battery.

Step 2: Add Resistors

Thread the leads of all 20 resistors through their holes on the wand mount.

Step 3: Solder Resistors

Each resistor is connected to an LED on one side and ground on the other.  Bend one of the leads of each resistor so that they are touching each other and solder them all together in a row.  Clip the excess metal from the leads.  Leave the last lead unclipped so that it can be attached to a wire later.

Step 4: Add Header Pins to Protoboard

Solder header pins to the pins connections on the arduino protoboard.  Make sure you are soldering them on the correct side!  For best results I recommend soldering the first and last pins first (as in figure 3), then check to see if the pins are straight and flat on the board (figure 4).  If they need to be adjusted it will be much easier with only two pins soldered down.  Once everything is lined up, solder the middle pins (figure 5).

Step 5: Attach Toggle Switch

Solder the toggle switch onto the middle of the arduino proto-shield as shown in the images above.  Solder a jumper wire between the side lead of the switch and the Vin pin on the proto-shield.

Step 6: Attach Battery Connections

Solder the red lead of the battery connector to the middle pin of the switch.  Solder the black lead of the battery connector to the ground pin of the protoshield.

Step 7: Wire Up LEDs

Attach wires to each of the LEDs on the wand.  As you solder each connection, clip the excess lead off the end of the LED (figure 3). 

Step 8: Connect LEDs to Arduino Shield

Strip the ends of each of the LED wires and connect to the pins of the arduino proto-shield.  Be sure to follow the pin connections below correctly, I've also attached the breadboard diagram from fritzing (figure 3), the left-most LED is the top of the wand and the right is the bottom.  In the schematic (figure 4) the left most LED is the bottom and and right most is the top.  You can find the fritzing file below.

Pin connections:

Top of wand
1                       Digital Pin 13
2                       Digital Pin 12
3                       Digital Pin 11
4                       Digital Pin 10
5                       Digital Pin 9
6                       Digital Pin 8
7                       Digital Pin 7
8                       Digital Pin 6
9                       Digital Pin 5
10                     Digital Pin 4
11                     Digital Pin 3
12                     Digital Pin 2
13                     Digital Pin 1
14                     Digital Pin 0
15                     Analog Pin 5
16                     Analog Pin 4
17                     Analog Pin 3
18                     Analog Pin 2
19                     Analog Pin 1
20                     Analog Pin 0
Bottom of wand

Step 9: Connect to Ground

Strip both ends of a (preferably black) wire and connect the unclipped resistor lead to a ground (gnd) pin on the arduino shield.

Step 10: Upload Firmware

Download the POV wand firmware below and upload it onto your arduino board.  If you have trouble uploading be sure that nothing is connected to digital pins 0 and 1 and that you have selected the correct board and serial port under the Arduino/Tools menu.

This code stores a set of binary arrays onto the arduino that generate each letter in the alphabet.  When the arduino reads the message you would like to display it compares each letter to one of its stored letters and then outputs the stored array column by column.  You will insert your own message into the arduino firmware in a later step.

Step 11: Attach Battery and Arduino Board

Use zip ties to secure battery and arduino to wand mount.  Flip switch to power on and off.  You should read the words HELLO WORLD on startup.

Step 12: Create Your Own Messages

Figure one shows the line of text you will need to edit to create your own messages.  Replace the worlds HELLO WORLD with any message in all caps with no punctuation.  You can create your own characters and images by generating matrices of 1s and 0s, follow the example given in figure 2, the letter J.
<p>This Code isn't compiling with Arduino 1.0.5.</p><p>I am using Arduino with AtMega8.</p><p>It is Showing this error.</p><p>Can you help?</p>
<p>write-- const boolean letterA [] ----- make it in this way</p><p>make it for all alpha and i'm sure it will work</p><p>i was in the same problem .... good luck for you</p>
<p>Hey this is only for Atmega328 and above, that's why</p>
<p>hi ashish once check the digital and analog pins of atmega8. and give properly in code. then it can works..,</p>
<p>Anyone know where I find the library &lt; avr / pgmspace.h ????</p>
<p>https://github.com/mikalhart/galileo-Pgmspace.h</p>
<p>C:\Program Files (x86)\Arduino\hardware\tools\avr\avr\include\avr\pgmspace.h :) I hope it was too late to reply! :D</p>
<p>Hi all I have here is the problem of what to do</p><p>exit status 1</p><p>variable 'letterA' must be const in order to be put into read-only section by means of '__attribute__((progmem))'</p>
<p>write-- const boolean letterA [] ----- make it in this way</p><p>make it for all alpha and i'm sure it will work </p><p>i was in the same problem .... good luck for you</p>
<p>at what speed of rotation of the wand can i visualize the output</p>
<p>question: Is it possible to use only one resistor between common gnd and gnd of arduino? I actually tryed to run bubble display once with only one resistor and it worked, so im just curious....</p>
you mean one resistor for all the LEDs? No - that will give you variable current through your leds depending on how many leds are on at once. Best case scenario, you will not be able to control the brightness of your LEDs, worst case scenario, you could blow an LED.
<p>sorry but I uploaded that code to my Arduino R3 already ( I had also replaced &quot; boolean...&quot; to &quot;const boolean... &quot; <br>But there is no led even light up ??? </p>
<p>@<a href="https://www.instructables.com/member/amandaghassaei/" rel="nofollow">amandaghassaei</a> can you give me the working code cause i cant run my program there are to many error when I try to compile my codes</p>
<p>Paste here the error log. Before you do that try to replace &quot;boolean&quot; to &quot;const boolean&quot; in all the code, it worked for me in this way.</p>
<p>here's the code that occured after i changed the values,. </p><p>Arduino: 1.6.1 (Windows XP), Board: &quot;Arduino Uno&quot;</p><p>Build options changed, rebuilding all</p><p>FYP1LVPH0OJ0IKJ.ino:678:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:706:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:734:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:762:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:790:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:818:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:846:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:874:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:902:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:930:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:959:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:987:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1017:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1046:49: error: 'sendToWand' declared as function returning a function</p><p>In file included from FYP1LVPH0OJ0IKJ.ino:26:0:</p><p>FYP1LVPH0OJ0IKJ.ino: In function 'void sendToWand(const boolean*)':</p><p>FYP1LVPH0OJ0IKJ.ino:1081:33: error: 'letterArray' was not declared in this scope</p><p>FYP1LVPH0OJ0IKJ.ino:1085:33: error: 'letterArray' was not declared in this scope</p><p>FYP1LVPH0OJ0IKJ.ino:1089:33: error: 'letterArray' was not declared in this scope</p><p>FYP1LVPH0OJ0IKJ.ino: At global scope:</p><p>FYP1LVPH0OJ0IKJ.ino:1103:51: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1131:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1159:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1187:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1215:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1244:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1272:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1301:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1330:49: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1358:51: error: 'sendToWand' declared as function returning a function</p><p>FYP1LVPH0OJ0IKJ.ino:1386:49: error: 'sendToWand' declared as function returning a function</p><p>Error compiling.</p><p> This report would have more information with</p><p> &quot;Show verbose output during compilation&quot;</p><p> enabled in File &gt; Preferences.</p><p>&quot;can you pls!! upload here the program that you used,. the program that is no need to be edited and ready to upload in an arduino&quot;</p>
<p>all you have to do is add &quot;const&quot; in front of the boolean letters; e.g. &quot;const boolean letterA ...&quot;</p><p>also change: &quot;void sendToWand(boolean letterArray[])&quot; <br>to<br>&quot;void sendToWand(const boolean letterArray[])&quot;</p>
<p>try using an older version of the Arduino IDE</p>
Hi again!! @mergim halimi. I already replace the &quot;boolean&quot; to &quot;const bolean&quot; but theres an error again<br><br>Arduino: 1.6.1 (Windows 7), Board: &quot;Arduino Uno&quot;<br><br>sketch_mar16a.ino:1:1: error: expected unqualified-id before '/' token<br><br>sketch_mar16a.ino:8:15: error: 'povtext' was not declared in this scope<br><br>sketch_mar16a.ino: In function 'void loop()':<br><br>sketch_mar16a.ino:858:9: error: 'povtext' was not declared in this scope<br><br>This is another error ive got can you help me to fix this??. Thank you
<p>try using an older version of the Arduino IDE</p>
Hi!! Did you change anything in thprogram or just the boolean to const boolean??? @mergim halimi
<p>plz give that code you used in ur pov and detail about the version of programmer </p><p>: </p><p>sunil32150@gmail.com</p>
<p>any suggestions on how I can mount this to a platform I want to have musical pov notes appear over a mp3 player im building </p>
<p>How far apart are the rows of LED's and resistors?</p>
<p>Where can I find the illustrator file for the lasercut?</p>
Is there any way to make a longer wand? I haven't used arduinos before.
<p>This is a really cool project!</p>
Codes are not verifying in arduino uno. Please can you send me a correct code at my email address. rajatnegi108@gmail.com
<p>it work perfectly on arduino 1.0.6 but new arduino version 1.6.5 not support it. plz correct this problem.</p><p>thank you. </p><p>my camera is not a good one ;)</p>
<p>hi amanda<br><br>i got a problem (error message) when uploading the program in arduino 1.6.5<br>can you fix it?<br><br>Arduino: 1.6.5 (Windows 7), Board: &quot;Arduino Uno&quot;<br><br>E:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avr-g++ -c -g -Os -w -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -MMD -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10605 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -IE:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino -IE:\Program Files (x86)\Arduino\hardware\arduino\avr\variants\standard C:\Users\CHATHU~1\AppData\Local\Temp\build7179824887335632129.tmp\FYP1LVPH0OJ0IKJ.cpp -o C:\Users\CHATHU~1\AppData\Local\Temp\build7179824887335632129.tmp\FYP1LVPH0OJ0IKJ.cpp.o <br><br>In file included from FYP1LVPH0OJ0IKJ.pde:26:0:<br>FYP1LVPH0OJ0IKJ.pde:79:19: error: variable 'letterA' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:102:19: error: variable 'letterB' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:125:19: error: variable 'letterC' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:148:19: error: variable 'letterD' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:171:19: error: variable 'letterE' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:194:19: error: variable 'letterF' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:217:19: error: variable 'letterG' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:240:19: error: variable 'letterH' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:263:19: error: variable 'letterI' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:286:19: error: variable 'letterJ' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:309:19: error: variable 'letterK' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:332:19: error: variable 'letterL' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:355:19: error: variable 'letterM' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:378:19: error: variable 'letterN' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:401:19: error: variable 'letterO' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:424:19: error: variable 'letterP' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:447:19: error: variable 'letterQ' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:470:19: error: variable 'letterR' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:493:19: error: variable 'letterS' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:516:19: error: variable 'letterT' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:539:19: error: variable 'letterU' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:562:19: error: variable 'letterV' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:585:19: error: variable 'letterW' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:608:19: error: variable 'letterX' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:631:19: error: variable 'letterY' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>FYP1LVPH0OJ0IKJ.pde:654:19: error: variable 'letterZ' must be const in order to be put into read-only section by means of '__attribute__((progmem))'<br>variable 'letterA' must be const in order to be put into read-only section by means of '__attribute__((progmem))'</p>
<p>i also had the same issue even with the Arduino IDE 1.6.5. change all the boolean variables to const boolean variables. it will work ! :)</p>
<p>plz give me the .hex file for atmega8 i have a atmel board.. with isp programmer plz</p>
<p>we must use 1.0.5 version it is good.., the next versions cannot be used. thoose will show some errors.</p>
<p>still giving error &quot;text overflowed by xxxx bytes&quot;.</p><p>Please help</p>
<p>can u plz send me the .hex file of this project.. I'm using the avr board with atmega8. i'v tried a lot with atmel studio 6 to get the hex file but it doesnt works .. so plz send me the .hex file for atmega8 @ yashusharma093@gmail.com plz... Thnku</p>
<p>hi.., the project is good.., there are some mistakes in program. after the last for loop some lines must be commented or else it will not shows more then one letter. plkease check it.</p>
<p>hey author i made a prototpe without using the resistors. everything else is same. When i run the sketch by usb power it works well but when i use a fully chaged 9 v battery, it runs for sometime and then reboots and after that whenever the code starts running it again reboots. To see it work correctly again, i have to wait for atleast ten minutes. Then when the code runs, the same problem persists. Is it due to not adding resistors? If so then is there a way to add them onto this prototype without desoldering and resoldering it? (Like on the ground wire or something else)</p>
<p>Hi guys, i wanted to somehow change the Pin connections order, but i think i need the library to do that, does someone have the library so that i can change that?</p>
<p>you kids are so cool - I love this!~!</p>
<p>Hi guys, im doing this project but i want to change the order of my pin connections, how can i do it in the arduino code?</p>
<p>Any One have POV project Report please send to my mail id nrmr2222@gmail.com</p><p>please it's urgent......</p>
<p>Hi Amanda, and others, I was wondering if we can upload a code in this project that shows the analog clock or digital clock. ( A beginner in arduino coding ) . Btw I made this, it works great, I just don't know how to make these pics, I tried to record a video but, hmm. not working, I changed the value of the refreshrate but almost the same, any suggestions ??</p>
<p>Hi Amanda, this project is great!, indeed i chose to replicate it for a school project, we do have a laser cuter, also a CNC Router to cut it out, but I can't see the adobe document to cut the wand :(, Can you tell me where it is? please, if you have the .DXF file it will be great!! Thank you very much, and great job!!</p>
<p>superb, i'll be trying this as my first project</p>
<p>Hi Amanda, As I said I worked on your project and it worked, but the problem is I ve to wave the Wand very fast in order to make the Alphabets visible. I even tried changing the delay, not working so fine. Wld you suggest me whether to increase the delay or to decrease to make it more attractive. Thanks in Advance</p>
<p>Hi Amanda, </p><p>I used your code, but made some changes </p><p>- I drew some alien faces, ships, star etc...instead of just letters</p><p>- I used a Ardiuno Nano v3 </p><p>- Used just 19 LEDs ( no space for 20th LED on my Circuit board)</p><p><a href="http://amitjain1980.blogspot.in/2014/11/magic-wand-based-on-persistence-of.html" rel="nofollow">http://amitjain1980.blogspot.in/2014/11/magic-wand...</a></p><p>Thanks</p><p>Amit </p>
<p>so cool!</p>
<p>Finished product</p>
<p>Thanks, cool :)</p>

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Bio: I'm a grad student at the Center for Bits and Atoms at MIT Media Lab. Before that I worked at Instructables, writing code for ... More »
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