Week 13: Applications and implications
This is something that I call good timing. The image, revealed this week by researchers from the Event Horizon Telescope (EHT), shows a bright ring of material surrounding a dark center that marks the event horizon of the black hole - the "point of no return, where nothing, not even light - can escape." and I wish this would relate to my project... ... and it is, a bit.
My final project is TARS, a robot from movie Interstellar. He will help me as demo setup for schoolchildren. Something to catch their attention. Interstellar is a great movie and surprisingly black holes described there are very similar to reality. Despite of being unlimited, sometimes our imagination is very precise.
What will it do?
Who's done what beforehand?
What will you design?
What materials and components will be used?
- Motherboard - ATMega328p, LCD screen, 2 MOS transistors (both arms), ISP header, sensor headers, 2 buttons with "debouncer" circuits
- Rainbow Generator - High power LED / series of White LEDs with relating passive elements (resistors, capacitors), CD- light scattering scraps
- Dark Sky Map Lamp - High power LED / series of White LEDs with relating passive elements (resistors, capacitors), Plano - Convex Spherical lens
Where will come from?
How much will they cost?
What parts and systems will be made?
What processes will be used?
What questions need to be answered?
How will it be evaluated?
What are the implications?
There are couple features. It will interact with user using thermistor, photoresistor, LCD screen and buttons. In two arms there will be two circuits, one for Rainbow Generator, which is lamp based on LEDs and light scattering Compact Disk (CD) and other one imitating Dark Sky Map. In this particular circuit I'm planning to use painted black lens with tiny holes and LED - based light source. Holes will be used to project small dots on the surface imitating night sky and light emitting diodes are efficient in terms of light power and drained current.
Everything will be controlled by so-called Motherboard. PCB featuring ATMega328p, controls both peripheral circuits. Using two buttons it will allow to turn Rainbow Generator and Dark Sky map (each arm separately). When playing with remaining sensors will visualize text on LCD screen.
I'm not planning to make TARS move in first version. However, further development may happen.
So far I was able to prototype couple parts during weekly assignments. Unfortunately, most of them I will have to upgrade or change but it was expected.
Motherboard, based on ATMega328p were made during Output devices week. I used it as prototype and thanks to it learned how to work with LCD screen and managed to learn dimensions
Both sensors (photoresistor and thermistor) were tested during Input devices week. Those circuits will be improved in future as well.
I also localized couple designs of Star projector and Rainbow Lamp, which I consider as background for my remaining two circuits.
Case will be 3D printed, it consist of three parts. I need to take care to catch all the details and plan it properly (fit all the electronics and LCD screen, cooling LEDs might be an issue). There are at least four circuits: Motherboard, Rainbow lamp, Dark Sky lamp, Interface. Motherboard will control peripherals. Code includes: working with LCD, turning on both lamps, measuring signals from two detectors, making use of buttons. If there will be enough time, I will create a mold with shape of rock to put TARS on it, it will be easier to handle and move around.
I'm planning to make good use of FabLab premises. I require some 3D printing using PLA, some elements (on the case) I will vinyl cut using standard materials. Three printed circuit boards will contain following elements
Most materials, I will be able to find in FabLab: 3D-printed components using any of the printers, PCBs will be fabricated on milling machines and most of electronic parts, black paint, silicone, copper foils are already prepared.
Materials that most likely I will need to buy: High-power LEDs, CD, some unexpected parts. I already have crucial - spherical lens.
At this point I estimate that total cost should not exceed 50 euro. However, I will create more detailed budget after I will succeed with final project. It will be included on some final project related web pages. I do not include pricing of my sweat and blood as those are priceless.
So far I have prototype of motherboard, interface board, working LCD screen and partially working sensors. I already designed both lamp circuits, they have to be milled.
Crucial part, keeping everything together is 3D printing. Electronics design and embedded programming pays huge role. There are a lot of planning how to put things inside in a logical manner. Plenty of handwork will be necessary.
I'm worried about poor output power of available LEDs (both lamps). It is probable that high power LED will be required. Then cooling might be an issue. There is also countless ways to interact with user, maybe quotes from the movie.
School children are severe judges. Let's see how they will like it. I have to make it bullet proof! Other than that, I would evaluate operation of each feature: LCD screen, buttons, sensors and finally rainbow generator and dark sky map lamp. It is very simple to check if screen, buttons and sensors are working properly, as LCD should visualize reaction on pressing buttons and detected temperature and light intensity. Lamps are a bit more challenging. I would like to reach decent output power on both lamps. Decent mean that I would be able to see rainbow and sky map on a wall one meter away from TARS (in a dark room).
Nevertheless I will evaluate every single circuit separately and describe it usability. Additionally, I'm planning to put everything inside of nicely looking cover (3D printed) and some decorations (2D cut). I will take a closer look of this part also.
3D design for case
Electronics Design - a lot of circuits
Embedded programming - it has to be controlled
