Elektor Special Project LEDs
September 2013
Inhalt
Vorwort 3
6 LED-Kommunikator
Design-Studie: Verwendung von handelsüblichen LEDs zur bidirektionalen Kommunikation
The author, Chris Coulston, processes the fact in his design that LEDs can both generate and detect light. The results are quite satisfactory in the current state of development. The units generate color sequences while paying attention to changes in light intensity. They detect these changes, interrupt the color sequence, receive a message, and adopt the color pattern contained in the received message.
12 Nachrichten-Ticker
Bau eines Internet-News-Tickers
This project provides for the extraction of headlines from news from RSS feeds and displays them scrolling on a dot matrix LED display. A news update is pulled from the net every 15 minutes.
24 BULI - Button-Lichtspiele
Effekte mit LED2812 und Cortex-M0+
The core of this instruction manual are RGB LEDs of the WS2812 type, in whose 6-pin housing the PWM controller is already built-in. The brightness of each RGB component can be programmed separately via a single line. 16 million colors can be displayed per LED. Since several LEDs can simply be connected in series, chains of up to 1024 LEDs are possible, all of which can be controlled individually.
59 The Matrix
Ansteuerung von LED-Matrixschaltungen
In a matrix circuit, the LEDs are grouped in rows and columns and controlled using a multiplexing method. Such a multiplexing sequence necessarily requires a more complex approach, but it is more efficient compared to the individual control of each LED. This article describes how the brightness of each individual LED can be controlled in multiplex mode. This results in the LED control sequence being divided into three levels in the time domain. The last section presents several ICs that are often used for controlling LEDs.
18 ALS es Licht wurde
Controller steuert Beleuchtungseinrichtungen nach Umgebungshelligkeit und Uhrzeit
With the help of modern semiconductor technology, it is no longer difficult to design a control system that measures the ambient light and controls the lighting in a predetermined way. The contribution is dedicated to the design of a lighting control system that switches a lamp on and off depending on the ambient light and the time of day. The described system is suitable for controlling any mains-powered lamps and uses an ALS (Ambient Light Sensor) among other things.
80 Über dem Limit
LEDs mit höheren Treiberströmen ansteuern
Developers should take advantage of the leeway that modern LEDs offer in terms of control current and temperature ranges. Many LEDs allow the construction of efficient lighting systems that require fewer LEDs and additional components – and without compromising on quality and lifespan. Those who rigidly adhere to binning information, on the other hand, miss optimization potential.
Praxis
- LED-Kommunikator 6
- Nachrichten-Ticker 12
- ALS es Licht wurde 18
- BULI - Button-Lichtspiele 24
Theorie & Anwendung
- DesignCorner: Schaltungen, Tipps und Kniffe 29
- Posistor gegen den Hitzetod 30
- High-Brightness-LEDs an Niedervolt-Stromversorgungen betreiben 34
- Derating mit PTC-Thermistoren in LED-Treiberschaltungen 37
- Der Umgang mit LED-Strings 41
- LED-Treiber für unterschiedliche Wandler-Topologien 45
- LED-Konstantstromtreiber in Schaltreglertechnik 48
- Grenzen überschreiten 55
- Ansteuerung von LEDs mit gepulstem Überstrom
- The Matrix 59
- Ansteuerung von LED-Matrixschaltungen
- Multitalent 67
- Controller treibt LEDs, regelt Solarzellen und lädt Batterien
- Dimmungstechniken für LEDs 71
Info
- OLED - Die Flächenlichtquelle 75
- Zum Entwicklungsstand der organischen Leuchtdiode
- 400 LED-Lampen auf dem Prüfstand 78
- Über dem Limit 80
- LEDs mit höheren Treiberströmen ansteuern
- Aktuell 83
- Neue LEDs, LED-Lampen, Treiber, Netzteile, Zubehör und Entwicklungs-Tools
- Inserentenverzeichnis 98
- Impressum 98
