Deepika Dipesh, Ebba Tornérhielm, Jenny Hanell & Xiangyi Wu
What is Sphaera?
Sphaera is inspired by the traditional crystal ball that gives the user a glimpse into the future. However, instead of foretelling big happenings in life, Sphaera reveals the weather forecast for the next twelve hours. It is designed to be a stationary artifact in the home environment, such as in the hallway, and can preferably be placed upon a drawer to ease interacting with it.
How does it work?
While interacting with Sphaera, the weather is projected as a hologram inside the glass globe. In order for the hologram to be visible without placing the globe in total darkness, half of the globe is painted in pure black. Five photoresistors are placed inside the globe and each one of them has its own functionality. For example, the current weather will be projected when covering the first one, while the forecast will be projected when covering the other four, where each one adds on +3 hours in time. If there is any question regarding the functionality, an instruction hologram could be projected at any time by pressing a button placed on the base.
What you need:
- Raspberry Pi 3 (model B) + keyboard, mouse and micro SD card
- A glass globe in preferred size
- A round piece of rather soft plastic (to be placed inside the globe for the hologram effect), the size depends on the size (diameter) of the glass globe.
- Fabric (~1*1 meter)
- LCD screen + HDMI cable & potential adapter (e.g. DVI/VGA)
- 5 CdS photocells
- 4 1uf capacitors
- 1 push button
- Breadboard + chords and heat shrink tubes
- Conductive thread (~10 meters)
- 9 tiny pieces of black sponge (2*1cm)
- A cardboard box (big enough to fit the screen)
- Items to stabilize the screen inside the box such as cellplast
- Bluetooth speaker
Observe: The items listed may be exchanged and any microcontroller with an intern/extern WiFi module may work, however, for this project the items above were used.
Step 1: Setup the Platform and Fetch the Weather Data
Step 2: Download Video Files
Download the video sources and paste them in the video folder on the Raspberry Pi. Adjust the location in the code to the preferred folder.
Video files available here:
Step 3: Paint the Globe
Paint half of the glass globe black in order to make the hologram clear. This is necessary to be able to see the hologram in a bright room. It also avoids the user to see the plastic that will be placed inside and therefore make the hologram experience more immersive. Also paint a black border or a nice looking pattern on the front's lower part if you don't want the user to see the LCD screen.
Step 4: Insert Photoresistors and Plastic
Place each photoresistor inside a black sponge with the top pointing upwards and the legs horizontally towards one of the short sides (see picture).
Connect the photoresistors to the breadboard and connect the breadboard to the Raspberry Pi (check out this tutorial).Test that the photoresistors are working by checking the value in the monitor.
Remove the chords from the photoresitors and cut the conductive thread in 10 shorter threads (~1 meter). Wire each thread around the photoresistors legs and use glue (super strong and unconductive) to make sure that they stay in place. Glue them inside the glass globe and spread out the threads so that they don't touch each other. Use black colour to paint over the threads for esthetic reasons.
Put four pieces of sponge around the round piece of plastic. Explore where the plastic should be placed by projecting a hologram. We recommend to put the screen in a tilted positions like on the picture. Put some glue on the sponges and insert the plastic in the desired position.
Step 5: Make a Button
Connect the button to GPIO20 on Raspberry Pi (see the circuit diagram below). Decorate the top of the button with a small plastic card to make it visible and pressable.
This button will show an instruction animation on how to interact with the globe. If this functionality is not wanted, just skip this step and remove the button related parts from the code.
Step 6: Cut a Hole in the Box
Cut a round hole in the middle of the lid and a little hole in the middle of the fabric and place it over the lid. Cut a star shaped form in the fabric in order to cover the lid's edge. Use tape to make sure the fabric stays in place.
Cut a little hole for the button. Squeeze the button into the hole and use glue/tape to make it stay in place. Make a little hole in the fabric for the button so it becomes visible from the outerside.
Also cut a hole on the back side of the box where the cables from the screen and the Raspberry Pi will be placed.
Step 7: Place Everything Inside the Box
Put the screen inside the box and use some lightweight material to stabilize it, such as cellplast. Place the breadboard wherever there’s room for it. Now there should be wires going from the breadboard to the photoresistors inside the globe through the lid.
Step 8: Circuit Diagram
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