Hanukkah Dreidel POV Display Using ATtiny85

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Introduction: Hanukkah Dreidel POV Display Using ATtiny85

I've made this Dreidel, SEVIVON (סביבון‎) in Hebrew, for the upcomingHanukkah, you can spin a virtual one here:

https://www.google.com/search?q=spin+a+dreidel

A dreidel isa four-sided spinning top, played during the Jewish holiday of Hanukkah, Each side of the dreidel bears a letter of the Hebrew alphabet: 'נ‎' (nun), 'ג'‎ (gimel), 'ה‎' (hei), 'ש'‎ (shin), represent the Hebrew phrase 'NES GADOL HAYAH SHAM' ("a great miracle happened there").

In Israel we replace the letter Shin with the letter 'פ'‎ (pe), to represent the phrase 'NES GADOL HAYAH POH' ("a great miracle happened here").

Basically it's the old times Spinner, you can read more about this ancient Holidays toy here:https://en.wikipedia.org/wiki/Dreidel

The inspirationfor this Instructable came from this well known Instructable, Thanks://www.smiletrl.com/ATtiny8545-POV-Displ...It has a great explanation of the physics behind POV display.

P.S.It is my first Instructable and as you probably already noticed, English is not my native language so please bear with me.

Supplies:

  1. 3D printer (I used myCreality Ender 3 V2)
  2. Arduinoor anATtiny85 programmer
  3. ATtiny85
  4. 8DIP Socket
  5. Breadboard
  6. Soldering iron
  7. 4 x 5mm White LEDs
  8. Toggle Switch
  9. CR2032 3V Battery
  10. CR2032 Socket
  11. 10uf Capacitor
  12. 0.1uf Capacitor(optional)
  13. Wires (22-28 AWG)
  14. Basic tools

Disclosure: The links abovecontain affiliate links你在不增加成本的情况,我可能获得small commission, this isthe exact BOM I used for this project from the samesuppliers I personally ordered from, Thanks.

Step 1: 3D Print All the Parts

I designed the Dreidel usingAutodesk Fusion 360 Personaland I highly recommended it.

I 3D printed each part by it self (had to test a couple of iterations on the handle for optimal fitting) using myCreality Ender V2. You get the optimal model and you can print all at once, or use different colors.

Slicing for the Ender 3 V2 was done usingCurawith the basic settings, nothing special, except for the infill:

  • Handle- 80% - about an hour
  • Cover- 100% - 3 hours
  • Base- 50% - 6 hours

The Cover and Base are fitting tightly and smoothly, you might need tosandpaper the edgeson the lips where they meet each other, you also want to make sure your printer is well calibrated.

Step 2: Soldering and Cover Assembly

Measure your wires roughly, there is plenty of room inside the base and you don't want to come up short.

Before soldering, Fit the LEDs inside their sockets and bend the legs, then take them out and solder.

Make sureyou solder everything outside the cover, PLA is very sensitive to heat and you can easily damage this part.

The only part I soldered,Carefully and quickly,while mounted inside was the LEDs cathodes, for solid fitting.

Assemble everything, I know the fittings are fragile sobe gentleand it should all snap fit, I'll probably design a second version for the cover with more robust fittings.

Step 3: Programing the ATiny85, Codding and Testing

First you will have to be able toprogram the ATtiny85, I learned how to do it from this great Instructable//www.smiletrl.com/How-to-Program-an-At..., Thanks.

(At the beginning I used a breadboard but later on I've built my own basicprogrammershieldfor ease of use, but it is not necessary).

For the codeI just simplifiedvishalaprcode and streamlined it for the Dreidel, using 4 pixels in a column instead of 5, and modify it for only 4 Hebrew letters.

#define delayTime 3 #define charBreak 6 #define LED1 0 #define LED2 1 #define LED3 2 #define LED4 3 #define charWidth 4 void setup() { pinMode(LED1, OUTPUT); pinMode(LED2, OUTPUT); pinMode(LED3, OUTPUT); pinMode(LED4, OUTPUT); } int g[] = {15, 10, 10, 11}; int h[] = {15, 8, 8, 11}; int n[] = {15, 9, 9, 1}; int p[] = {15, 9, 9, 13}; void displayLine(int line) { int myline; myline = line; if (myline >= 8) {digitalWrite(LED1, HIGH); myline -= 8;} else {digitalWrite(LED1, LOW);} if (myline >= 4) {digitalWrite(LED2, HIGH); myline -= 4;} else {digitalWrite(LED2, LOW);} if (myline >= 2) {digitalWrite(LED3, HIGH); myline -= 2;} else {digitalWrite(LED3, LOW);} if (myline >= 1) {digitalWrite(LED4, HIGH); myline -= 1;} else {digitalWrite(LED4, LOW);} } void displayChar(char c) { if (c == 'g'){for (int i = 0; i < charWidth; i++){displayLine(g[i]); delay(delayTime);} displayLine(0);} if (c == 'h'){for (int i = 0; i < charWidth; i++){displayLine(h[i]); delay(delayTime);} displayLine(0);} if (c == 'n'){for (int i = 0; i < charWidth; i++){displayLine(n[i]); delay(delayTime);} displayLine(0);} if (c == 'p'){for (int i = 0; i < charWidth; i++){displayLine(p[i]); delay(delayTime);} displayLine(0);} delay(charBreak); } void displayString(char* s) { for (int i = 0; i <= strlen(s); i++) { displayChar(s[i]); } } void loop() { displayString("n g h p"); }

In case you want toadd more letters, graphics and icons, vishalapr, in hisInstructable at Step 9, explains the math behind this special display and how it works.

Or you can just use my spreadsheethttps://drive.google.com/file/d/16xpVROUolVtDFwU0d...whichsimplifyit and auto calculate each column for you, just play with the 1's and 0's.

After playing with thedelay timesfor best outcome I've setdelayTime to 3andcharBreak to 6, it depends on the surface you spin on and your force, so just play with the numbers for best results.

Attachments

Step 4: Play!

Turn it on,coverthebase,screw the handleand just play.

Happy Hanukkah!

Step 5: Conclusion and Future Upgrades

As I quickly learnedmy design have some cons and to be honest with you,I'll list all of them below, and try to suggest solutions and workarounds:

  1. Flimsy fittings on the cover——我希望能够上传新版本的cover with stronger fittings, but, if you just assemble it for the first time and don't take the circuit apart, you should be good.
  2. Poor Balance- the Dreidel balance is not so good, probably because the circuit weight is not evenly mounted, if you just attach the handle to the base without the cover, it spins perfectly and smoothly, I'll try to add some weight at the bottom of the base to counter the cover weight.
  3. Inaccessible Toggle Switch- mounted inside makes you remove the cover for each use and shutdown - this can be easily fixed by replacing the toggle switch with aVibration Sensor switch like the SW-18010Pwhich will make the dreidel On automatically when it spins.
  4. Short Readable Display Time- Because the Dreidel has no power, it starts with the speed you gave it and decelerate until full stop, standard POV displays count on a steady speed for smooth display, I already started to investigate a solution:adding a gyro - MPU6050- and calculating the display delays on the fly. This solution will leave me with one less pin for the LED's so I'll have to upgrade to WS2812B LED strip utilizing only one pin for the data, it will also make me upgrade the power source... :) if it all works out I'll post another instructable - Dreidel V2.

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    2 Discussions

    0
    tweeto

    Tip9 hours ago

    Here is a quick way to balance the Dreidel:
    1. Put some masking tape on the cover's flat side.
    2.Try to balance it on the tip of your finger by adding some washers.
    3. Fix it with some epoxy glue (you can use the leftover to strengthen the inner fittings).

    I managed to double the spinning time and it feels much smoother.

    2
    Penolopy Bulnick

    6 days ago

    Thanks for sharing! Nice job making this :)