Here’s a proximity-sensing LEDs project by Will_W_76. He writes a complete step-by-step instructions:
So how does this all work? What makes it proximity-sensing? Remember in the explanation above that the photo-transistor acts like a switch. So when the photo-transistor is off, no current is flowing across it to our blue LED and the LED is off as well. Now look at the other side of our circuit. That’s where the IR LED is connected, and it is connected such that it is always on and emitting 880nm infrared waves. Remember that I also mentioned the photo-transistor is set to respond best to wavelengths of 880nm? That’s how the proximity-sensing works! When an object (such as your hand) goes over this little “cluster”, IR light of 880nm is emitted from the IR LED. This light reflects off of your hand and back to the circuit. When the photo-transistor picks it up, it turns on allowing current to flow through from the source to our blue LED lighting it up!
Proximity sensing LEDs - [Link]
by Deddieslab :
I have a couple of front door LED lights which I would like to switch on automatically during the evening/night. The two conventional methods that are commonly available had their disadvantages:
A timer switch is the easiest and cheapest solution, but doesn’t take into account day light savings. Besides that, in Einhoven, the Netherlands where I live in december the sun sets around 16:30 while in June it doesn’t get dark before 22:00. A simple timer doesn’t take that into account either.
Since you only want the lights on when it gets dark, instead of time you can also use a light sensor to distinguish day and night. You have these front door lights that have this built in. The problem that I had with these devices is that they start bouncing (‘flickering’) around sunset/sunrise. They constantly turn on/off which causes damage to the LED lights I was using. This cost me already several expensive led lights.
Frontdoor light switch based on local sunset/sunrise - [Link]
ReturnZero published a stroboscope build:
At its heart, a stroboscope is just a rectangular wave generator hooked up to a light source. I wanted a few extra features to make it nice to use:
Ability to set flash rate by either frequency or RPM
Set duty cycle of output without affecting flash rate
– 2×16 for displaying RPM, frequency and duty (one per line, so one will be hidden at any time)
Rotary encoder (with button) for main interface
– When button is not pressed, knob will increase/decrease the value of the selected digit
– When button is pressed, rotating knob will scroll through display digits
Buttons for quickly halfing/doubling thirding/trebling the flash rate
– This is useful for checking that you haven’t hit on a multiple of the rotation rate
Nice beefy output stage for switch big sets of LEDs
DIY stroboscope - [Link]
Spacewrench over at Dorkbotpdx writes:
I had some spare 4-digit 7-segment LED displays and some AT90USB82s, and I’d always intended to do something with them. This was probably the easiest thing! It’s just the AT90 driving the display, with a(t least) 4 wires controlling it: Vcc, GND, MOSI and SCK. (I haven’t written the code yet, but my plan is to make the display accepts characters via SPI and then spends the rest of the time displaying them).
The board has footprints for a 16MHz crystal and USB connector, so you could make it a USB-enabled 7-segment display as well. I stuffed those parts on my test board, but I’m not sure whether the USB actually works. You can power the display from USB, at least, although the video shows it being powered over SPI (which is the same connection I use to flash code).
Standalone SPI 7-segment display - [Link]
by Boris Landoni @ open-electronics.org:
Since when white light emitting high brightness LED are available, the handover from traditional lighting bulbs to the solid-state lighting has become irreversible: LEDs have an efficiency (expressed in lumens/watt) higher than that of almost all the traditional lamps (except, at the moment, the large sodium vapor lamps used for street lighting, unusable in closed environments for the high power required and the chromatic aberration they produce) at a cost that is today less prohibitive than it was a few year ago. They are indeed very sturdy and have a very acceptable ratio of luminous flux and size.
The perfect Remote, Programmable, Controller for interactive LED strips - [Link]
by BABU TA @ edn.com:
This flasher/beacon circuit can be employed as a distress signal on highways, a direction pointer for parking lots, hospitals, and hotels, etc. The circuit uses a power LED, and provides more light than a typical incandescent lamp flasher. Use of a 6V or 12V SLA lantern battery makes the circuit portable.
HB-LED flashing beacon repurposes switching regulator - [Link]
My first attempt at an LED Aquarium light started as an excuse to buy some of those LED light strips off of eBay. I gutted the old 18″ fluorescent fixtures and soldered together row after row of 18″ RGB LED strips. They mounted to a thin aluminum plate I screwed into the old light housings. I mounted one of those remote-controlled RGB LED controllers in there with a 12V 5A power brick. The remote control let us change the colors, and had a few blinky light modes that I’m sure the fish didn’t appreciate too much. My wife loved it, which is all that really matters.
Aquarium Light V1 - [Link]
In this episode Shahriar takes a close look at programming the popular NeoPixel RGB LEDs using a PIC microcontroller and C-language. A close-up of the NeoPixel (WS2812) LED is shown with attention to identifying various semiconductor elements inside the package. The principle operation of the LED is the described along with a detailed explanation of the pins and the one-wire communication protocol.
A simple evaluation board for the PIC18F4550 is used to drive a circular array of 60 NeoPixel LEDs from Adafruit. After presenting the difficulties of providing an accurate pulse-shape using the C-language, the measured waveform is shown on a Tektronix MDO4000B. Finally, the code for a circular color rotating pattern is presented and demoed. The code for the experiment can be downloaded from The Signal Path website.
Tutorial on Programming the NeoPixel (WS2812) RGB LEDs - [Link]
Pup05 shared his SmartMatrix project. He writes:
The panel fits perfectly, just had to shim it with a little bit of folded card stock on each side. There’s plenty of room for the Teensy and SmartMatrix board, wiring, SD card, etc. I cut out a piece of white printer paper to size, and placed it between the panel and the glass for a bit of diffusion. The magnetic feet that came with my panel from Adafruit fit perfectly, and keep the panel pushed against the paper and glass. I cut a notch in the bottom of the back, just big enough for the power cord, USB cable, and IR receiver.
I loaded up Craig’s LightAppliance sketch and made a few minor modifications, loaded up my SD card with the animated GIFs I wanted, and everything works great. Unfortunately, I already had my Teensy soldered on to the SmartMatrix board, and didn’t feel like pulling it off to solder the RTC crystal on to the back. I might do that later, and add the temperature sensor.
SmartMatrix project - [Link]
by Daniel @ nupo-artworks.de :
I started this project 2 days before we went to France for a 2 week holiday but since this is a really quick project the lamp worked fine after 2 days. Now when we came back I gave it the last touches and finished some bugs in the software.
Initially this lamp should be a replacement for a lamp in our living room but I was way too greedy with the WS2812B LEDs. Eventually, the lamp wasn’t bright enough so I’m going to mount it now in the sleeping room as one of those morning, sun imitating lamps. As a controller I’m going to use a Raspberry PI with a node script that will also control some other devices in my house like my Wall Clock.
IKEA ceiling lamp LED modification - [Link]