Project Applications and implications

What will it do?

  • Its a lamp or a nightlight

  • However, it is also a centrepiece and canvas for telling stories.

Stories that have trees in them - tales of Yggdrasil from Norse mythology, or of the Kalpavriksha from Indian mythology. The story of the Serpent and the Apple in Eden, or a vision of the Buddha under the Bodhi tree.

The individual RGB LEDs of the tree can be controlled with code to showcase various patterns of the light, and colours, blinking and other effects can be used to symbolise characters or events.

The different story-schemas are triggered by the touch sensors which are the steps at the base of the tree.

The current set of stories encoded are

  • The KalpaVriksha - this is the wish fulfilling tree of Indian mythology, and the default state for the lamp. The LEDs light up in series from Right to Left with random somewhat-muted colours, and a 20% probability of a very bright colour.
  • Odin hanging on the Yggdrasil - A blue light on the lowermost branch symbolises Odin, while the heart of the tree is White, and random shades of green light up the rest of it.
  • The Serpent and the Apple - A bright green light symbolises the serpent in the Garden of Eden, and the rest of the tree lights up in shades of green, with a randomly placed red for the apple from the tree.
  • Under the Bodhi tree - A bright orange glow symbolises the Buddha sitting under the Bodhi tree, which is green, depicting scenes of his enlightenment as well as teaching his disciples under the tree.

Who's done what beforehand?

The entire concept, to the best of my knowledge, hasn't been done before.

Playing with Neopixels in various formats is all too common, and there are dozens, if not hundreds, of examples out there. Specific colour control, in this manner, is again something I haven't seen, but may very well exist within a larger application.

Step response sensors have a rich history. Multiple point ones are less common but have been used in Fab projects as well. Apart from Neil's example, and Adrian Torres' work which has become such a Fab standard reference, these are some interesting works I tracked down, referred to or took inspiration from, mostly from pre-Adrian times

What will you design?

  • The superstructure of the Tree shaped PCB
  • 4x step response PCB, with touchpads (based on the basic step response that I did for the Input Devices week)
  • The base and enclosure for everything
  • The code to drive the LEDs and colours according to the story schemes (starting from the basic Neopixel code I worked on during Output Devices week)

  • Mold for resin cast diffuser in front of the lights

  • The devboard for the RP2040, has already been designed by me for the Electronics Design week and milled out for the Manufacturing week

What materials and components will be used?

Electronics :
Parts

  • WS2812 RGB LEDs
    • Single Neopixels
    • cut up from a strip of WS2812 with 60 LEDs/metre - this is the less expensive as well as easier to solder version
  • XIAO RP2040
  • 2 sided copper clad PCB
  • 1 sided copper clad PCB
  • header pins, straight as well as 90 degrees
  • 1M ohm resistors

Consumables

  • jumper wires
  • heatshrink tubing
  • solder or solder paste

Materials :

  • PLA filament
  • Acrylic sheets (3 mm)
  • Copper wire

Where will they come from?

  • Electronics :

    • Robu.in
    • Lamington Road, Mumbai
      • Bombay Electronics
      • Visha World
      • Champion Rubber

  • PLA filament :

    • Robu.in

  • Acrylic Sheets :

    • Disha Plast, Jogeshwari, Mumbai
    • Arihant Plastics, Mumbai

  • Copper wire :

    • Kika street / Gulaalwadi, Mumbai

How much will they cost?

Electronics :

  • WS2812 RGB LEDs (Rs 477 for strip of 60 LEDs)
  • XIAO RP2040 : Rs 799/-
  • 2 sided copper clad PCB : Rs 250/- (20 cm x 30 cm)
  • 1 sided copper clad PCB : Rs 220/- (20 cm x 30 cm)
  • header pins, straight as well as 90 degrees (~Rs 50 per pack of 5 strips of 40 pins)
  • 1M ohm resistors (Rs 50 for pack of 100)
  • jumper wires (Rs 40 for pack of 40 cables, MM, FF, MF, 10 cm or 20 cm)
  • heatshrink tubing (Rs 6 per meter, pack of 20 m)
  • solder or solder paste (Rs 25)

Materials :

  • PLA filament (Rs 1200 per kg)
  • Acrylic sheets (3 mm) (Rs 120 per sq ft)
  • Copper wire (Rs 800 per kg)

Bill of Materials

The total comes to about INR Rs 2505.00, or approximately USD 30-35 if converted.

What parts and systems will be made?

  • Tree superstructure, with
    • LEDs,
    • routed paths to connect them,
    • headers instead of Vias to connect the front to the back
  • 4x step sensor with 4 touch pads

  • Devboard to hold the RP2040 and connect the subsystems to it easily

  • 3D printed Base and top parts, as a sandwich construction to hold all the internals together

  • Another smaller sandwich to hold the PCB tree and diffusers in place, while keeping them easy to remove from the main body. This set of part will attach to the base from above, not within the sandwich.
  • One of the base parts will expose the touch pads as steps climbing up to the tree while still holding them in place

What processes will be used?

  • 3D Printing
    • multiple parts in the base
  • Lasercutting
    • the front and back diffusers for the tree superstructure
    • spacers
  • Electronics design
    • WS2812b strip version - part, symbol and footprint for this, since it's not a standard part/not available in the usual NeoPixel/WS2812b/Adafruit libraries
    • The Tree superstructure with multiple LED locations with the requisite paths and conditions to connect the LEDs
    • The 4x Step Response sensor board
    • The DevBoard from the XIAO RP2040
  • PCB milling
    • Milling for each of the PCBs listed above,
    • Special mention for the Tree superstructure which was a critical, double-sided PCB that was the centre piece of the whole project
  • Casting and molding
    • Silicone mold and resin cast for a diffuser in front of the tree to have better lighting effects

What questions need to be answered?

  • Can Cu wire be inlaid into engraved Acrylic ? How ?
  • Can a PCB also become a structure, as well as showcase centrepiece ?

How will it be evaluated?

It has to fulfil a few basic functions : - It has to light up(!) - It has to respond to touch on the touch pads/step response plates and light up accordingly - It has to be visually interesting and engaging - It has to be the abstraction of a tree and communicate that - It should be easy to code new story schemas in the future