Tiny Rangeela

This is a fun colourful project for those who are beginners in electronics. One can develop an interest in this field by making their own toy. Also, it can be used as an attractive decorative piece too. One can also extend this project on the different microcontroller to make it controllable with mobile Bluetooth or with Wi-Fi. adding custom colour modes, patterns or so.

This multicolour lamp changes its colour from time to time in fixed patterns. The name 'Tiny' initially came as Attiny Microcontroller is being used and also the lamp is so handy (as it is tiny!). 'Rangeela' comes from an Indian word meaning 'colourful'. As a child, I was very fond of colours. These colours attracted me to build an interest in painting, sketching too. With this project, I explored colours electronically! xD!

Let us see how to approach towards making this handy toy.

For this we require some components to be purchased online or offline:
The links mentioned here are available in the Indian subcontinent. You can search for a similar product in your respective countries.

• Attiny85 or Attiny45
• Copper Clad (Approx 6x4inches): https://www.roboelements.com/product/4-x-6-inches...
  
• Anhydrous Ferric Chloride (FeCl3): https://www.roboelements.com/product/anhydrous-fe...

• Hacksaw: https://www.amazon.in/Bosch-SR-1686-2608003031-Co...
• Watchmaker's File (Fine grit): https://www.amazon.in/SunRise-5-Piece-Soft-Grip-D...
• Wire Cutter (Multitec): https://bm-es.com/product/multitec-nipper-cutter/...
• Soldering Wire: https://www.roboelements.com/product/venus-lead-f...
• Solder Rod (25W or more): https://www.electronicscomp.com/soldron-25w-230v-...
• Resistors - 10k ohm(1/8 or 1/4Watt) x 4pc,
  10ohm (1/2Watt)x 3pcs,
  330ohm(1/8 or 1/4Watt) x1pc
• Capacitors - 10uF(Polar), 0.1uF (ceramic) ....both 1pc
• BC337 transistors TO92 package x 3pc
• Omron 10xx push button
• Female and Male burgstrip. 1pc strip each
• 3mm red or green LED for power indicator
• 3Watt RGB LED (having 6 pins total)
• 5V-1A or 5V-2A Adapter
• 8pin IC base/socket DIP package x 1pc: https://www.sunrom.com/p/8-pin-ic-socket
• Resistor spacers x 6pcs
• PCB spacers X 4Pcs: https://www.sunrom.com/p/pcb-spacers-6mm-height
• DC Jack connector: https://www.sunrom.com/p/dc-socket---1mm-legs---s...
• Acrylic Transparent Spray
• Sandpaper of fine grit

This is a very important step in making any project, be it electronic, mechanical or of any other field. If we cannot visualise or formulate what we want in the end, there is no point in starting. Otherwise, one can divert from the main objective and leads to a waste of time and resources.

Here in this project, we have planned to make a lamp whose colour changes automatically. We will be using Attiny85 (you can use Attiny45 too for this project). The RGB LED has been planned to be on an elevated surface so as to spread the light without being restricted by PCB components.

Another thing to keep in mind that to drive 3W LED we require large currents (more than 100mA) which will generate heat and this heat can damage other components. So for this, the 10-ohm resistors have to be kept far from the microcontroller. Also, these resistors will be elevated from the PCB with the help of spacers.

In PCB designing with large current consumption, there is a need for a ground plate so that it dissipates as much heat as possible.

The third thing to keep in mind is the size specification. I have made this project to make it portable, so I have made it as compact as possible. If I had spread out the components, the PCB would have been large which is a waste of resource and area.

Here is the schematic of the Tiny Rangeela. In this stage, we define what all electrical connections we need and with what components. This file has been created by Autocad EAGLE software.

(Various tutorials are available on internet regarding EAGLE CAD software, to begin with.)

After deciding the circuit. We will then lay our components. The heat dissipation components to be kept far apart whereas other components close enough. Above photo is the final design I have made. This design is not the only possible design. One can get their own creativity working and can place the components according to their own choice as far as the circuit constraints are kept in mind (here, heat dissipation factors and keeping the PCB handy in size).

The first Image is the raw layout of components.

The second image is after attaching the ground plate all over the PCB.

(The red text seen in images is for the top layer. The blue one represents the elements of the bottom layer.)

As stated earlier, the RGB module was planned to be kept on an elevation to avoid blocking of light by circuit components. Here is the separate eagle design made for RGB led. As you can see there is a lot of red coloured patches. This has been created deliberately to dissipate heat generated by 3W LED.

This module will be placed over Attiny85 on the two connectors placed on its sides. (Seen on the image of the previous step if you hover your mouse over it)

After finalising the board layout, finally comes the fun task, Fabricating the PCB.

The process starts with taking out a laser print of the PCB design on a 180gsm glossy paper.

The copper-clad has to be rubbed on the copper side by sandpaper to remove the oxidation layer. Sanding has to be done in one direction (either up-down or left-right)

The portion of print denoting the PCB was cut out and placed on copper clad with printed side on the copper and ironing over the paper for about 10min.

IMPORTANT: While taking out print, please ensure that the bottom layer is mirrored. Otherwise, if it is printed as it is, it will get reversed (mirrored) and the whole design will go waste.

After ironing, the paper was removed. If the ink hasn't stuck on copper-clad do not iron again. Fill the gaps with a permanent marker. Also if there is paper still stuck at an unwanted place, remove it with the needle otherwise that portion of copper won't be removed while etching.

Then the PCB was etched in FeCl3 solution, made by mixing 3 teaspoons of FeCl3 with 1 glass of water.

After etching in sunlight for about 20min we will see the result as in the first image above.

Now, after washing the PCB and scrubbing all the black ink left, we will get our board looking like the 2nd image.

It is mandatory to spray 'Transparent Acrylic Spray' on the copper side to avoid corrosion of copper with time.

Finally, solder all the components referring to the schematic.

Woohoo! The hardware part has been implemented.

Now just a small step and we are ready to go.

Upload the code in Attniny85 from the link: https://github.com/SwapniilK099/Tiny-Rangeela/tree...

(If you don't know how to upload code in Attiny, you can search it on Google. There are numerous tutorials available.)

Once the PCB is ready, try lighting the lamp by putting any white cap/ paper structures etc and play with it. Here I have put an empty medicine container.

Finally, to protect the PCB and other hardware, you can design your own enclosure.

Here I have used cardboard.

I have arranged a transparent dome structure found on Rotating Disco Lights available in the market. It has numerous cuts been made on the dome which disperses light in several directions. This added beauty to the lamplight.

Hope you all liked the project. Do give it a like.

Message me if any queries below in the comments or on my Instagram ID: https://www.instagram.com/captain_xyglossy099/?hl=...