ba0sh1.com reverse engineered a cheap LED voltmeter he bought from Taobao and made it run on a I2C bus. He writes:
I’m planning to build a EEVblog-ish constant dummy load for battery and power supply testing. Dave in his build used a LCD voltmeter for the display. In the senseless pursuit of difference, I tried other display solutions including character LCD, graphics LCD, OLED, TFT, AMOLED, IPS, which resulted in several previous blogs but nothing ends up to be satisfactory. Along with the complexity grows exponentially from one solution to another, I slowly start to feel the importance of KISS concept, keep it simple stupid. All I need is just a number display, nothing fancy, nothing pricey, nothing takes my attention away from the analog circuitry. I decided to go back to the basic 7-segment LED display. “Simplicity is the ultimate sophistication”, how elegant it is!
Hacking a cheap LED voltmeter - [Link]
Don´t let yourself get confused by miniature dimensions – small SMT LEDs produce surprisingly strong light.
SMT LEDs enjoy a big popularity because of their size but also thanks to a fast and simple assembly to PCB on automatic machines. In comparison to wire-leaded types, a vast majority of SMT LEDs doesn´t contain optics, thus radiating in a wide beam angle. That´s why is their light visible even from wide viewing angles and at the same time it enables to easily reach a uniform backlight of panels, displays, …
From the smallest SMT LEDs you can find in our store sizes „0603“ (KP-1608) and „0805“ (KP2012) from company Kingbright. Particularly in the Kingbright. Particularly in the KP-2012 series can be found several types with a luminous intensity in the order of hundreds mCd. A novelty in the Kingbright portfolio are series SR-J4 (640 nm – red) and series ZGK (525 nm – green) comprising LEDs of various dimensions. For example the new type KP-2012SRC-J4 (640 nm) has a luminous intensity of up to 600 mCd (@20mA).
In general, all KP series LEDs are low-profile (thin), but at extreme space requirements, the solution exists in an ultra-thin version KPT (only 0.75 mm height – KPT2012).
Naturally, it´s not always necessary to have a high light output (for example at indoor usage), that´s why at several types can be found a version with a higher and also with a lower luminous intensity, what is usually also reflected in a price of a given type. In stock we keep the most requested types suitable for majority of applications. Should you have interest in types which we don´t keep in stock, please don´t hesitate to contact us at email@example.com.
Small but powerful LED series KP- 2012 – [Link]
Seven segment LED displays are known to be resource and power hungry. But because they are visually so charming and readable from a far viewing distance and at a much wider viewing angle as compared to any other electronic displays, they are still hugely popular. The required number of I/O pins to drive the LED segments can be reduced significantly by using an additional dedicated hardware. For example, the MAXIM’s MAX7219 device allows you to interface 8 pieces of seven segment LED modules using only 3 I/O pins of Arduino or any other microcontroller.
High-voltage seven segment LED display driver with SPI interface - [Link]
LEDger Led (polarity) tester:
Everytime I solder a SMD LED on a pcb I have to turn on one of my multimeters and flip it over to diode-test mode and then probe the SMD LED to see which connector is the anode and which is the cathode. The LEDger is a small PCB with a button cell battery and smd footprints that allows me to, while still holding the LED in my tweezers. just hold it onto one of the footprints and see if it lights up or not.
LEDger Led (polarity) tester - [Link]
DOT. @ instructables.com
I and my friends like to have fun in summer. We like to fool around with music when we are camping. To make those parties more likely to professional ones I have made portable 9V LED strobe. For my surprise it really gives a big effect. I hope you will like it!
DIY portable LED strobe - [Link]
While LED based solid-state lighting continues to gain ground, and several major challenges have been solved, some still remain. Energy savings and the savings that a long product lifetime brings certainly have spurred adoption in a long list of applications. Cities, sports facilities, retail, medical, residential and industrial use, are all on the rise. The move to LED-based solid-state lighting is gaining ground based on the promise of energy savings and long lifetime.
Six LED challenges that still remain - [Link]
This wearable LED heart simulator pendant was inspired by my work as a cardiovascular surgical nurse as well as my love of electronics. It simulates the electrical activity of 17 different rhythms and when paired with the heart backplane, it becomes an audio and pulse simulator as well.
Wearable LED heart simulator pendant - [Link]
Here’s a tutorial from Maxim on how to design smarter LED lighting. [via]
How smart is your LED lighting system? While LED lighting holds the promise of reducing energy consumption and maintenance costs, smart LED lighting designs improve system performance in both areas, achieving higher performance per watt and reducing cost in the long term. Energy measurement, ambient light sensing, and communication serve as the cornerstones of smart LED lighting design. Energy measurement provides system health and consumption information. Ambient light sensing reduces an LED’s on-time, conserving energy and extending diode lifetime. Communication links together each luminaire for identification of maintenance and system level coordination. The contribution of components to the overall system performance will be explored.
App Note: Adding intelligence to LED lighting - [Link]
The circuit is powered by a PIC12F683 microcontroller and source code is included.
PIC12F683 Mood vase - [Link]
deflater @ instructables.com writes:
You’ll be the talk of the town when you wear this obnoxious, oversized, completely impractical wristwatch. Display your favourite foul language, song lyrics, prime numbers, etc. Inspired by the Microreader kit, I decided to make a giant watch using similar sixteen segment displays. Twelve hours later, I came out of my masochistic fugue and stopped trying to route a sixteen bit data bus on a single sided pcb small enough to wear on your wrist. Returning to my digikey box of mystery, I came up with a four character display made up of 5×7 led matrices. 7 bit parallel data input, no need for umpteen current limiting resistors, upper and lower case characters, the rest writes itself.
Programmable watch with DLO3416 four character display - [Link]