22 December 2014

A MythTV Remote Control without LIRC

  • Relatively easy to build
  • Emulates a keyboard, so it needs no driver
  • Costs around 10 €
  • Is easy to configure, in under one minute
  • Works with most remote controls
  • Can easily be customised for other HTPC software

I was always very fascinated with Objective Development's software implementation of a USB driver for Atmel controllers called V-USB. On their web site, they have a nice list of really interesting projects using this driver.

There are a few projects that translate IR remote control signals into USB HID key strokes. This has one huge advantage: You don't need any driver or software on the PC. I had use for this, since I am using a PC with MythTV to watch TV. The standard means to control it is an IR remote with LIRC.

But with LIRC I had some mixed results . It is quite a universal and versatile tool. This means you need to do a lot of configuring. You have to edit several files and it is not straightforward. And the teaching phase has always been trial and error for me.

With a microcontroller decoding the IR protocol, one part of the bothersome configuration is eliminated. And the second part can be relatively easy, as only a simple IR to key stroke assignment is needed.

31 October 2014

The Eyes - A Last Minute Halloween Effect

Halloween is a rather new tradition in our part of the world, but my family is very enthusiastic about it. Tombstones are built, bones are scattered in our front garden and a fog machine is kept in the basement for just this one day of the year. This time I thought that I could contribute a little LED effect. My idea was to use a couple of red LEDs to create a red-glowing eye effect, like some evil little monsters lurking in the dark.

6 February 2014

The Morse Thermometer - Part 3

Putting it all together
In part 1 and part 2 of this posts I investigated and designed the components for a solar-powered Morse thermometer. In part 3 everything gets connected.

In order to get the most out of the collected sunlight it is important to use as little power as possible. A red LED is a good choice here, because it only has a forward voltage of 1.7 Volts. So it will consume only about half the power of a white LED with a forward voltage of about 3.3 Volts.

Perhaps you remember that I had found out that even when the LED is not lit, the boost circuit from the solar lamp draws about 7mA. So it was important to switch it off during the time the thermometer is in stand-by.

Let's have a look at the original lamp circuit again.