This project shows how to build a Spectrophotometer using a toilet paper roll, duct tape and a graphing calculator. Light is shined through a sample solution, passes through a diffraction grating, then shows up as bands of color on the projection surface. The photosensor can slide back and forth along the spectrum to get readings at different frequencies using a multimeter. [via]
DIY Spectrophotometer - [Link]
In this article Michal Zalewski shows how to build a Threat level indicator. Michal painted the back of some plastic black and then used a CNC machine to mill the letters into the painted side. Then it can can easily be back lighted using some LEDs. There is also a knob to select the threat level. [via]
Threat level indicator - [Link]
Want to learn more about the Antikythera Mechanism? View the video above.
The Antikythera Mechanism: http://bit.ly/fm4oFK is the oldest known scientific computer, built in Greece at around 100 BCE. Lost for 2000 years, it was recovered from a shipwreck in 1901. But not until a century later was its purpose understood: an astronomical clock that determines the positions of celestial bodies with extraordinary precision. In 2010, we built a fully-functional replica out of Lego. Sponsored by Digital Science: http://www.digital-science.com a new division of Macmillan Publishers that provides technology solutions for researchers. Available under a CC-BY-3.0-Unported license.
Lego Antikythera Mechanism - [Link]
This project shows how to build a LED holiday tree using a custom made circuit board. The circuit board is made using a Dremel rotary tool and doesn’t require any etching chemicals. You use the Dremel tool to cut a copper into a tree shape and route the two separate PCB sections that will power the LEDs. The LEDs and resistors will be soldered at the surface of the board. The result is pretty nice. Check the construction PDF on the link below.
DIY custom circuit board holiday tree - [Link]
Jeri shows how to make a point contact transistor with germanium and phosphor bronze contacts. She cracks some 1N34 diodes to harvest the germanium to build the transistor. Before that she explains in details the physics of semiconductor operation. Finally she tests the transistor in a circuit to find out that it is really working! [via]
Make a Point Contact Transistor at home – [Link]
This project shows how to build a cold coffee (frappe) Machine using plain build materials. On the pages below “Giorgos Lazaridis” describes the procedure of building the coffee/sugar tanks, the raising/lowering mechanism that will blend the coffee and the rotaing glass table. He has to overcome many challenges to achieve his goal and he describes all them in his website. This project is under development.
Instant Cold Coffee Machine – [Link]
MOSIS, short for Metal Oxide Semiconductor Implementation Service is a service that enables you to share wafer space on the fabrication process of a semiconductor. That is a batch order service for custom ICs with reduced manufacturing cost. In practice you share the costs of a single IC fabrication run with other designers. This service is mainly available for Universities and start up companies but Scot Satre of Satre Electronics has used this service for his ASIC ICs.
DIY Integrated Circuit Design with MOSIS - [Link]
Jeri shows how to make blue electroluminescent (EL) powders from common ZnS:Cu green glow powder.
Make Electroluminescent (EL) Ink at Home – [Link]
This article discuss how to make your own LiIon batteries using obsolete Li-Ion pack able to power a robot. The overall cost is about 10$ to build a 14.4V 2.2Ah Li-ion pack. Read about the procedure on the link below.
Making your own lithium-ion batteries – [Link]
This project shows how to build a laser projector using an Arduino, a heptagon pillbox, a cooler fan and a laser pointer. Check how it works and construction details on the link below. The heptagon pillbox scan the projection surface and produced the words. [via]
Because the mirrors are moving the reflected laser dot sweeps the screen from left to right, because it does it very quickly your eyes actually see an horizontal solid line, in this case you see 7 lines one on top of the other because the each mirror is at an angle.
DIY laser projector – [Link]