Kurt Skauen writes:
This is a description of how I designed and built my UV exposure box. After experimenting a bit with dry-laminate photo-resist and liquid UV hardened solder mask I decided to stop trying to improve my toner transfer technique and rather build a proper UV radiation unit for making printed circuit boards.
I wanted it to be powerful and compact so I decided to use UV LEDs as the UV source. The preferred wavelength for the LEDs would probably be 365nm, but those LEDs turned out to be hard to find, and very expensive. The 395nm-405nm LEDs on the other hand are very inexpensive. And best of all, can be bough as high-density LED-strip’s on 5-meter rolls. So I bought two “5M Ultraviolet 395nm 3528 SMD LED” rolls that have 120 LEDs per meter for a total of 600 LEDs per roll. From what I could tell from a bit of googling the wavelength should work even though it is not ideal. Initial tests proved that the 395nm LEDs worked very well.
DIY Double Sided 60W LED UV Radiation Unit With Vacuum Pump – [Link]
by codebender_cc @ instructables.com:
An RGB LED has 4 pins, one for each color (Red, Green, Blue) and a common cathode. It has tree different color-emitting diodes that can be combined to create all sorts of color! Any color is possible depending on how bright each diode is.
How to use an RGB LED – Arduino Tutorial – [Link]
The LT3952 is a current mode step-up DC/DC converter with an internal 60 V, 4 A DMOS power switch. It is specifically designed by Linear Technology to drive high power LEDs in multiple configurations. It combines input and output current regulation loops with output voltage regulation to operate as a flexible current/voltage source. The LT3952’s 3 V to 42 V input voltage range makes it ideal for a wide variety of applications, including automotive, industrial and architectural lighting.
60V LED Driver with Internal 4A Switch & PWM Generator – [Link]
I was extremely satisfied (and proud) of the way that the enclosure turned out for the rework of my 7490 Clock. The electronics on the other hand, is another story.
The innards of that clock were from a prototype I built in 2001. It was a proof of concept. It led to the design of what would become an extremely well-polished and accurate clock.
Since it was one of the first things I ever built, I decided to put it in an enclosure of its own and consider it too as a finished product.
The problem was that the prototype never ran properly. It worked, just not as well as it should. Needless to say, I tried to fix it in the way of an Arduino upgrade. On paper everything should run perfectly, but in the real world, it just doesn’t. The clock bounces all over the place. It’s more of a random number generator than a clock. I really thought that moving away from the 60Hz line signal as a timebase to a solid 1Hz signal from a DS3231 RTC would solve all my problems. At the end of the day, it boils down to the fact that it’s all soldered together on a DIY homebrew PCB. The holes that I drilled are too big for the pins; resulting in some pretty shoddy-looking soldering. It’s a noisy circuit, and I’m sure there’s some grounding issues in there too.
Large 7-Segment Clock – [Link]
Designing a CC LED driver – Following on from Part 1, I design some code for a Microchip dsPIC33FJ16GS502 microcontroller to user the high speed PWM module to drive a high power LED at a constant current.
Constant Current DC-DC LED Driver Design – [Link]
by Tustin High T-Tech @ instructables.com:
The purpose of this small scale LED marquee is to display messages to our classroom in a more modern and centralized way. In the classroom, this construction would save white board space and is convenient because it can store a large amount of information. It is also fairly simple to program and has a mount, making it easy to place anywhere within the classroom setting.
64×16 RED LED Marquee – [Link]
In this article Raj over embedded-lab.com shows us how to measure our heart rate using Arduino UNO, his Easy Pulse Plugin and 4-digit SPI seven segment LED display module. It computes the heart rate by processing the analog pulse signal output from the Easy Pulse Plugin sensor and displays it on the seven segment display module.
Arduino measures heart beat rate from fingertip – [Link]
This design is a type of indicator that is used in voltage reading. It operates as an indicator rather than a meter that drives LED for voltage indication. Voltage thresholds are 1.5, 3, 4.5 and 6V. Above each incremental threshold an additional LED turns on.
LED DC Voltage Indicator – [Link]
by Ole_L @ instructables.com:
If you wanna build a fancy led matrix display with only a few pixels, this is exactly what YOU need!
-WS2812(B) LED strip
-A piece wood
-7 jumper wires
-7 female pin headers
10×5 RGB LED Matrix with only 5 IO pins – [Link]
by Scarab Hardware :
Ambient lighting is a technique that creates light effects around the television that correspond to the video content. It has been pioneered by Philips under the brand Ambilight. In this project we will create a basic FPGA-based ambient lighting system that reads the video signal over HDMI. This means we are not limited to computer output. We can use it together with DVD players, video game consoles, etc.
DIY FPGA-based HDMI ambient lighting – [Link]