Tag Archives: Led

Single Channel SMD Relay Driver


Single Channel Relay Board is a simple and convenient way to interface a relay for switching application in your project.


  •     Input supply 12VDC @ 42 mA
  •     On Board 5V Regulator provides 5V output
  •     Output SPDT Relay
  •     Relay specification 5 A @ 230 VAC
  •     Trigger level 2 ~ 9 VDC
  •     Header connector for connecting power and trigger voltage
  •     Relay operations status LED
  •     Power LED
  •     Tiny Design
  •     Screw terminal connector for easy relay output connections

Single Channel SMD Relay Driver – [Link]

Building the Colossus LED Display

by Adam Haile @ maniacallabs.com:

The 2014 NC Maker Faire was a huge turning point for Maniacal Labs. It was there that the idea for the AllPixel and what is now BiblioPixel got their start. It’s also where we showed off our first custom-built LED display, the 24×24 LPD8806 matrix. At nearly 24 inches square, and 1 pixel per inch, it was certainly impressive. But we left the Maker Faire with a desire to go bigger. Not just more pixels… but physically larger. Much larger. We call it “Colossus”.

Building the Colossus LED Display – [Link]

Driving LEDs


Emanuele @ dev.emcelettronica.com published an article on how to drive LEDs:

The LEDs (Light Emitting Diode) are diodes whose basic characteristic is the ability to emit light when they are passed through a current that flows from P to N region. At each recombination between the charge carriers (electrons and holes), on PN junction region, a photo emission is generated, and the total quantity of emitted photons, and therefore the light intensity, is proportional to the current intensity that passes through them. The emitted light has a spectrum – wavelengths distribution – that is defined according to the materials used in the realization of the diode PN junction, although it partially depends on the current intensity and on the junction temperature.

Driving LEDs – [Link]

Smart Garden


by FABLAB Dhahran @ instructables.com:

In this project we will design and program a smart garden watering system. This system will use Arduino UNO and a moisture sensor to measure the volumetric water content in soil. It will also have a light (photocell) sensor to detect when the plant should get sunlight. So, when the soil is dry a red LED will light up, when it’s wet a blue LED will light up, and when the plant needs a light a white LED will blink. You will need basic 2D-designing skills and CNC machine to design and build our own planter box. Alternatively, you can just use a normal jar. Also, you can make your planter box using acrylic and cut it by a laser cutting machine.

Smart Garden – [Link]

A Connected Lamp to Wake Me Up


Limpkin has modified his IKEA lamp to use 10W LEDs.

So for some reason I bought 2 IKEA lamps at a flea market. As IKEA furniture has a long history of being hacker-friendly, I figured they shouldn’t be an exception to the rule.
My plan? Fit a few 10W RGB LEDs in there together with an ESP8266 to use the final result as an alarm clock.

When you are dealing with a LED consuming that much current, you can’t simply use a series resistor as the latter would need to dissipate R*I² in heat. I’m therefore using a dedicated LED driver that automatically adjusts the LED voltage to match a given current. As you can guess, it isn’t much different than a standard step-down and just uses a shunt resistor to measure the current flowing through the LED.

A Connected Lamp to Wake Me Up – [Link]

Fake TV Security Light


by Marcus Jenkins:

This gadget steps up the game from leaving a light on at home when you’re out. Place it near a window to make it look like somebody’s at home watching TV.

The idea of leaving a light on at home while you’re out is to give the burglar an uneasy feeling that somebody’s at home and it might be worth trying the next house along instead. A TV on at night plays a constantly-changing light-show against your window which really does say I’m at home and I’m awake. Of course, you could leave a real TV on but that’s an eco-disaster since TV’s consume 50W at best and hundreds at worst. Plus you might not want to be burning your TV in for days on end if you’re not at home.

Fake TV Security Light – [Link]

Voltage indicator transitions between colours


by Einar Abell @ edn.com:

This Design Idea gives two versions of an indicator light that changes from green to red as a battery discharges. There are many circuits that do this sort of thing, but all the ones I have seen are too complex and costly for my taste. This DI shows a method that uses an absolute minimum of low cost parts: a dual-color LED and four other parts.

Voltage indicator transitions between colours – [Link]

Colour Injector lamp


by Taras Sgibnev:

The colour of light emitted by this lamp can be controlled using syringes filled with red, green and blue ink. Russian designer Taras Sgibnev developed the interactive product as a physical expression of the way red, green and blue light are used in digital interfaces to create a full spectrum of different hues.

Colour Injector lamp – [Link]