Let’s get the most important out of the way: This project is heavily inspired by the one conceived by Sander Mulder. If you haven’t come across it by now, check it out!
After having had the Sander’s screensaver version (available at the website) running on my computer for some time, I started thinking about making a similar device.. No surprise, that the hardware from the ‘Kettlers of Satan‘ project turned out a obvious choice shortly after. Melwyn / Haujobb agreed to help with the software and so, the project was underway! :)
As this unit was given as a birthday present to the friend who sent me the link to Sander’s project (hi Joonas!), the construct had to be made way more clean than the one made for Kettlers. This time, I decided to rotate the floppy drive and move the connectors so that they all are on the edge that’s facing down when unit is hung on to a wall. Despite the unit can be reset by powering off / on, I decided to add a reset switch for extra convenience (say, should f.ex. the Pqng software crash). The picture frame was left out altogether.
The power supply is a recycled laptop transformer, otherwise the hardware is similar to the Kettlers one. So I won’t bother documenting it again here.. Not that I bothered photographing the build either, so the photos of the completed unit on this post are by Joonas :). Thanks mate!
If monolithic DC/DC converters wouldn’t be used, the unit could be powered from a +12V supply. In such a configuration, only a internal +5VDC converter would be required. For better efficiency, it should be of switch-mode variety. I’ll definitely keep the +12V approach in mind, but it also depends a bit on which kind of power supplies I manage to find in the dumpster. As I’m well-stocked with these (recycled) monolithic converters, they’re the choice to go with whenever a laptop power supply is available.
As a clock, this device is pretty basic. The software doesn’t f.ex. have any automated adjustment for standard / daylight savings time. If time needs to be adjusted, a P/S2 keyboard has to be hooked up, the system rebooted and the system clock settings changed from the BIOS. The fact that a) the system boots using a floppy drive and b) the TFT backlight is cold-cathode fluorescent lamp (CCFL), this isn’t actually the most energy saving clock.
When running with minimum operating voltage (+16VDC), the power consumption tops close to 1A with maximum display brightness, then settling to around 900mA. Turning down brightness control a bit (hardly any visible change in brightness) reduces the consumption to 800mA and with minimum brightness (picture barely visible) it drops to 470mA. The unit itself draws around 450mA with the backlight disconnected.
From these figures, it’s easy to see the impact of CCFL brightness; the lamp is hogging almost 50% off the overall power consumption with maximum brightness! Modding the display to use LEDs would certainly help a lot. Just for further comparison, connecting a keyboard adds about 150-200mA. The one I have is a really old one, presumably newer ones might draw a little less. Getting the system to boot from some other media would help too.
The name ‘Pqng’ has a bit of finnish-electronic-music-act (1, 2) sort of vibe in it for a reason. Apparently, Sander had received a cease&desist from Atari for using the official name of this classic tv-game, eventually managing to settle for a limited run.. Not sure if he even paid a licensing fee in the end. Given the status this game has in popular culture nowadays, I’m pretty sure Atari is well-prepared to cash in on it every chance they get.
Copyright infringements put aside, despite Pqng is a one-off giveaway, having a unique name for the project is more fun anyway :).