4 June 2016

Arduino Disco Ball Cake


 

Description

This is a fun project that will surely impress anyone you make this for. If you are having a "Disco" themed party, you cannot have a boring old cake. Let me tell you, this is probably the only Arduino project that my wife has ever been willing to be a part of. She did the hard work of putting the cake together, and I, well.... I was in charge of lighting. My biggest fear was that one of the wires would come loose and ruin the event at the most critical moment... While a wire did come loose, I managed to fix it in time before the guests arrived. Ok enough of my monologue, let me show you how to make one of these things.

 


Parts Required:


Arduino Libraries and IDE

You can get the Arduino IDE from here: https://www.arduino.cc/en/Main/Software
I used version 1.6.4, which is probably way out of date... but works fine nonetheless.
 
You can get information about how to use the FastLED library here: http://fastled.io/
And you can download it from here: FastLED Library
I used version 3.0.3, which is also probably out of date.

ARDUINO CODE:

ARDUINO CODE DESCRIPTION:

  • FastLED Library: You need to make sure that you have downloaded and installed the FastLED library into your Arduino IDE. The library is included in this sketch otherwise the FastLED functions will not work.
  • The "NUM_LEDS" variable: tells the Arduino how many LEDS are in use. In this case, we have 4 LED rings, with each LED ring containing 16 LEDs, and therefore a total of 64 LEDs. If you define a lower number, for example 16, then the sketch would only illuminate the LEDs on the first LED ring.
  • The "DATA_PIN" variable: tells the Arduino which Digital Pin to use for data transmission to the LED ring. In this case, I am using Digital Pin 9.
  • Other variables: I have a couple of other variables which are used for LED randomisation and hue control. Hue is the colour of the LED. By incrementing the hue variable, you can get the LEDs to cycle in a rainbow-like pattern. The "hue" variable is a "byte", which means that it will only go up to a maximum value of 255, before it jumps back down to zero.
  • Initialisation Code: If you have a different LED ring to the one in this tutorial, you may have to modify the initialisation code. This LED ring has a WS2812-B chipset (according to the ICStation website), and so this line:
     
    FastLED.addLeds(leds, NUM_LEDS); Will tell the FastLED library which chipset is being used (NEOPIXEL), the pin used for data transmission (DATA_PIN), the LED array to be controlled (leds), and the number of LEDs to be controlled (NUM_LEDS).
  • In the "loop()": section of the code: the "hue" variable is incremented to create a rainbow effect, and a random LED is selected using the FastLED's random8() function.
  • The random8(x) function: will randomly choose a number from 0 to x.
  • The randomSeed() function: is there to help "truely randomise" the number. This is helped by reading the randomness of a floating analogPin (A0). It doesn't have to be analogPin 0, it can be any unused analog pin.
  • leds[rnd].setHSV(hue,255,255): This line sets the random LED to have a hue equal to the "hue" variable, saturation equal to 255, and brightness equal to 255. Saturation equal to zero will make the LED shine white.
    Brightness of zero essentially turns the LED OFF.
  • FastLED.show(): No physical changes will be made to the LED ring display until a message is sent from the Arduino to the Digital input pin of the LED ring. This message is transmitted when you call the FastLED.show(); function. This tells the LED rings to update their display with the information contained within the led array (leds). So if you set all LEDs to turn on, the board will not illuminate the LEDs until the FastLED.show(); function is called. This is important to know - especially when trying to design your own LED sequences.
  • The delay(50) line: will set the amount of time between flashes to 50 milliseconds. You can change the delay to increase or decrease the number of flashes per second.
  • The leds[i].fadeToBlackBy( 180 ) function: essentially fades the LEDS by 180 units. You can increase or decrease this number to achieve the desired fade speed. Be warned however, that if you forget to call this function or if you fail to fade the LEDs sufficiently, then you may end up with ALL LEDs turning on, which could potentially destroy your Arduino board - i.e. depending on the number of LED rings you have, and how you have chosen to power them.

 

The Cake


  • Slide 1 - Base Plate: It is important to create the base plate with all of the electronics fitted and in working order BEFORE you put the Cake onto it. Trying to fit wires/cables LEDs and circuits under the base plate while there is a Cake ontop is a recipe for disaster. So prepare the base plate first, and then move to the cake making part later.
  • Slide 2 - Bake Cake: You will need a couple of hemisphere cake pans to make the two sides of the ball. You have to make a relatively dense cake to withstand the overall weight of the cake, icing and fondant, and to maintain it's shape. Once cooled and chilled, you can place them ontop of each other to form a sphere. They are held together by a layer of icing between them.
  • Slide 3 - Fondant Icing: The fondant icing has to be rolled out on a special non-stick mat. We found that adding a bit of flour helped to reduce the stickiness. There are special rollers which ensure that the thickness of the fondant is consistent throughout. You then have to cut them into square pieces (about 1 cm squares worked well for us). The squares are then painted Silver with a special/edible silver fondant glaze. You may need to use a few coats, and allowing it to dry between coats.
  • Slide 4 - Iced Cake on Base: The cake can either be iced on or off the base plate... probably better to do it off the base plate. But if you decide to do it on the base plate, you will need to protect the LEDs from stray icing that may fall from the cake (in the process). Once the cake has been fully iced (with icing/frosting), you will need to place the cake into the central position on the board. There may be a chance that the cake may slide from the base... so do what you need to do to make it stay put.
  • Slides 5-7 - Place Fondant Squares: While the icing is still soft, you will then need to quickly, methodically and tirelessly place the fondant squares in a horizontal linear pattern around the cake. Work your way towards the north and south poles of the cake doing one row at a time. You can cut a fondant circle for the north pole of the cake. In slide 7, you will see a hole at the top of the cake. This was made to cold a plastic canister inside, which would be used later the hold the decorations in place at the top of the cake. Do this before placing the fondant circle at the top of the cake.
  • Slide 8 - Add Glitter: After placing all of the fondant squares onto the cake, it is very possible that some of the Silver glaze may have been wiped off some of the squares. This is where you go over it again with a few more coats of silver glaze, and on the last coat, before it dries, you can sprinkle some edible glitter all around the cake to give it that extra shine.
  • Slide 9 - The end product: The final step is to add some wire sparklers and some other decorations to the top of the cake. Push the wires through the fondant cap at the north pole into the canister within. This will hold the wires in place without ruining all of your hard work.


LED Ring pins

  • WS2812-B chipset: This LED ring uses the WS2812-B chipset, and has 4 break-out pins
    (GND, 5V, Din, Dout)
  • Power: To power this module, you need to provide 5V and up to 1A of current
  • Signals: To control the LED ring, you need to send signals to it via the Digital Input pin (Din).
    You can connect another LED ring to this one by utilising the Digital Output pin (Dout)

 

Power Usage Guide

  • General Rule: Each individual LED on the ring can transmit Red, Green and Blue light.The combinations of these colours can make up any other colour. White light is made up of all three of these colours at the same time. Each individual colour will draw approximately 20mA of current when showing that colour at maximum brightness. When shining white at maximum brightness, the single LED will draw approximately 60mA.
  • Power multiplier: If each LED can draw up to 60mA and there are 16 LEDs on a single LED ring, then 16x60mA = 960mA per LED ring. To be safe, and to make the maths easier, you need to make sure that you provide enough current to accommodate 1A per LED ring. So 4 LED rings will need a 5V 4A power supply if you want to get full functionality out of the modules.


 

Fritzing diagram

Connecting ONE LED Ring to the Arduino- (Click to enlarge)


  • 3 wires: You only need 3 wires to connect to the LED ring. If you only plan to light up a couple of LEDs at any one time this should be ok.
  • The SAFE WAY: A safer way to do this is to use an external power supply to power both the Arduino and the LED ring.
  • Electrolytic capacitor: By connecting a large 4700 uF 16V Electrolytic capacitor between the positive and negative terminals of power supply leads, with the negative leg of the capacitor attached to the negative terminal of the power supply, you will protect your LED rings from any initial onrush of current.


  • Protecting Resistor: It is also advisable to place a 300-400 ohm resistor between the Arduino's Digital Pin 9 (D9) and the LED Ring's Digital Input pin (Din). This protects the first LED from potential voltage spikes
  • Suitable wires: If you plan to chain a few of these LED rings together (see below), then you will probably want to keep the wires as short as possible and use a decent guage wire that can handle the current being drawn through them.


 

Connecting TWO LED Rings to the Arduino- (Click to enlarge)


  • Three extra wires:You only need 3 extra wires to connect an additional LED ring. A wire needs to connect the Digital output (Dout) of the first LED ring to the Digital Input (Din) of the 2nd LED ring.
  • Stay safe: Once again, a safer way to do this is to use an external power supply, a large electrolytic capacitor at the terminals, and a 300-400 ohm resistor between the Arduino and the first LED ring's digital input pin.


 

Connecting FOUR LED Ring to the Arduino- (Click to enlarge)


  • Sixty Four LEDs:You need 3 extra wires for each additional LED ring. 4 LED rings provides a total of 64 LEDs.
  • Watch the AMPS:At full brightness, this setup could potentially draw up to 4amps (or roughly 1 amp per LED ring)
  • External Supply essential: It is essential to use an external power supply to power these LEDs when there are so many of them. If you don't use an external power supply and you accidentally illuminate ALL of the LEDs, then you are likely to damage the microcontroller from excessive current draw.


Connection Tables

How to connect ONE LED Ring to the Arduino- (Click to enlarge)


How to connect TWO LED Rings to the Arduino- (Click to enlarge)


 

Concluding comments

In this tutorial I showed you how to go about decorating a Disco Ball cake and also showed you how to use the RGB LED rings from ICStation. If you look at the video you will see just how versatile these LED rings are. I would like to thank my wife for providing such an exciting project to work on, and ICStation for their collaborative efforts. Please make sure to share this project with all of your friends and family.
 






If you like this page, please do me a favour and show your appreciation :

 
Visit my ArduinoBasics Google + page.
Follow me on Twitter by looking for ScottC @ArduinoBasics.
I can also be found on Pinterest and Instagram.
Have a look at my videos on my YouTube channel.

24 April 2016

Arduino Stroboscope Animation





UPDATE: Magzor has just started a Kickstarter campaign. Please check it out to get a good package deal on many of their components. Many of which were used in this tutorial.
 
This tutorial will show you how to build your own Stroboscopic Animator using Magzor's Mechanotronic Design Portal as a starting point. Magzor Corporation is a business in California that is trying really hard to simplify robotic design. They want to enable users with little to no engineering experience to design and manufacture a custom robot by themselves in a matter of hours.
What is a stroboscope? A stroboscope is an instrument that uses a strobe light to make a moving object look stationary… We will use this feature to create an interesting 4 picture animation on a rotating disk.

 

 
Have a look at the video below to see the project in action, and the MDP process walk-through:


 

Video




 
 

Parts Required:





 

Magzor Schematic Diagram

Click to zoom ...

 
Further build instructions can be obtained by selecting the components in the Mechanotronics Design Portal within the Magzor website. Generating the build, and then selecting "Setup Instructions" tab at the top of the page. See video above to see this process in action.
 
 

Arduino Sketch


Make sure to copy and paste the following code into your Arduino IDE. It doesn't seem to work directly from the browser. You also need to install the Arduino Magzor I2C library ( http://magzor.com/downloads/ )



 

Putting it together


 
Arduino MEGA


 
Magzor I2C board


 
MIC Boards


 
MIC Boards Assembled


 
Sensors, Modules and Shields - all put together


 
Motor with Bracket and Wire


 
Picture lined up with magnet on disk


 

Stroboscopic Animation



 


 


The Arduino MEGA microcontroller listens for the hall effect sensor to be triggered by the south facing side of the magnet on the underside of the rotating disk. As the magnet moves over the hall effect sensor, the sensor is triggered and the Arduino instructs the LED to blink for a fraction of a second. By manipulating the delay after the trigger time, we can get the LED to blink when one of the four images on the rotating disk is towards the front position. And if we get the timing right, we can make a simple animation.
 
If you watch the video above, you will see that the image bounces around a little bit. The duration of each frame is determined by the speed of the rotating disk (or motor), and the number of LED flashes per frame. Any changes in rotation speed will affect the position of the picture when the LED blinks. My rotating disk is not completely semetrical or centred correctly, and therefore a bit jumpy… but you get the idea. Bold images with high contrast seem to work best… Precision is key for this type of project. And if you can get the disk to rotate at a constant speed, you could probably do away with the hall effect sensors and magnets… however, in my case, these were essential in getting the project to work as intended.
 
This project is a lot of fun. You can really get creative by making your own pictures or 3 dimensional models (for a stop motion effect). Try different colours. It really is quite cool.



Concluding Comments


I would like to thank Magzor for supplying the components used in this tutorial, and letting me try out their MDP process. I really like the concept, the one stop shop which looks after you from beginning to end. Providing everything I needed to get the project off the ground. The point of this exercise was to go through the entire process of selecting the parts, build the project, and get it up and running. And I have done that in no time at all.
 
There is only one library to download and install, and the good thing is that you don't have to go hunting for it. The latest "correct" working version of the library is easy to find, right there on the Magzor website… Speaking of the Magzor website, please make sure to take a quick look around. It is quite impressive.
 
  UPDATE: Magzor has just started a Kickstarter campaign. Please check it out to get a good package deal on many of their components. Many of which were used in this tutorial.





If you like this page, please do me a favour and show your appreciation :

 
Visit my ArduinoBasics Google + page.
Follow me on Twitter by looking for ScottC @ArduinoBasics.
I can also be found on Pinterest and Instagram.
Have a look at my videos on my YouTube channel.


 
 
             

This project would not have been possible without the collaborative effort from Magzor Corporation.
Please visit their site and check out the MDP.



However, if you do not have a google profile...
Feel free to share this page with your friends in any way you see fit.