USB charging adapter for bench power supplies

USB charging adapter

USB charging adapter

Many gadgets and tools nowadays run from 5 V and incorporate an USB port for that purpose. When developing those devices powering them from a bench power supply is usual very handy as current can be easy monitored and limited. For that purpose I wanted to create a small adapter which plugs into my bench power supplies and offers an USB type A plug.

The power and current a device may draw from an USB port is limited and follows complex rules depending on the state of USB enumeration. Many devices ignore those rules and just draw 100 mA or 500 mA independently of USB enumerate state. This works for most power providing devices and almost all USB chargers/power supplies. If more current is needed the power supply needs to signal extra capability to the device. As most USB chargers are rather dump a simple solution, or to be exact many simple solutions were invented. The device that wants to draw current checks the status of the D+ and D- signal lines immediately after attach. Continue reading

LED Display

LED display @ Maker Faire

LED display @ Maker Faire

Last year I mentioned a long term project I'm working on: A huge LED display built out of 32x32 LED RGB matrix modules driven by a BeagleBone Black, which could drive the display like a usual monitor using a framebuffer driver. After many months and just right before Maker Faire 2015 in Hanover I managed to bring the project in a presentable state. This article shall give an overview over the project. Continue reading

Maker Faire Hannover 2015

Dieses Wochenende fand die dritte Maker Faire in Hannover statt und nachdem ich 2013 und 2014 nur als Besucher vor Ort war, habe ich mich dieses Jahr auf dem Stand des Chaos Computer Club Hannover als Maker versucht. Bei uns am Stand gab es neben einem Lötworkshop viele Bastelprojekte zu sehen: Unter anderem hatten wir verschiedene selbst-gebaute Tastaturen, Snake auf Flipdot Displays, Multiplayer Tetris auf einem LED Laufschriftmodul, einen LED-Effekt-Koffer, meine Time Circuits und mein LED Display dabei. Das am Stand viel blinkte und es viel auszuprobieren gab, waren wir die ganze Zeit von vielen Kids und Junggebliebenen belagert, welche entweder für sie neue Spiele (Die 'Jugend' kennt kein Tetris mehr) oder Altbekanntes ausprobieren wollten.
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Upgrading HP 6060B DC Electronic Load with front binding posts

HP 6063B Front Binding Posts

HP 6063B Front Binding Posts

A few weeks ago I scored an HP/Agilent/Keysight 6060B DC Electronic Load on eBay. Unfortunately most of these come without front binding posts as they are optional (Option 020) and have to be paid extra for. As I'm using this as a bench DC load and not in a rack-mounted test setup I wanted to have these. Luckily I had access to a HP/Agilent/Keysight 6063B DC Electronic Load with front binding posts, which is basically the same DC load with just less current and more voltage specs. Continue reading