Monday, October 31, 2011

The Waxybottom expedition

In 1918 a British expedition led by the intrepid Nigel Q. Waxybottom set out for a small island east of Bimini in search of the tomb of the tyrannical King Whatalottahooie. They were never heard from again. Some say they were lost to the sea, while others claim they fell prey to the curse of the candy king...

This was how I greeted my TOT's...

(sorry about the dark vid - more on that below)

All in all things went well this year, in spite of the few hiccups I had. The kids really loved it.

Lessons learned:

When you find something you want to use in your haunt, buy it then.

I found some really awesome green nylon camo netting at a local surplus store that I'd planned to use as a backdrop for the entire display, but didn't buy it when I first saw it. Then when I went back for it last weekend, they were sold out. D'oh!

When you build custom parts or effects, don't use oddball parts you can't easily replace.

I built some LED flood lights using some really high power LED's. I didn't have a 12V power supply with enough current capacity to power them (wanted something more weather tight than a PC power supply) so I used a 19V supply from an old printer I had laying around. The power supply died & I didn't have another one to replace it, nor did I have time to change out the resistors in the lights so I could use a different voltage. Wasn't a huge deal, but the yard was quite a bit darker than I wanted.

On another note, I've come to the conclusion that the skull I used for the idol is cursed itself & I shouldn't use it again. I've repurposed it for different props 4 times now, & every time it's broken on Halloween night. I think from now on it will be a static prop...

Happy Halloween all!

Saturday, October 29, 2011

A little last minute testing

Sorry for the shaky video.

Sunday, October 9, 2011

Sunday, October 2, 2011

Sunday, July 24, 2011

Calculator software

I've done a bit of (very simple) computer programming in the past - mostly scripts to automate some server actions & reports - but never anything with a GUI. Recently, however, a change in some procedures at work has prompted the need for some custom software to bridge sales tracking and cash handling (yawn...). So what the heck does that have to do with Halloween?!? Not much, really, except that in the process of wrapping my head around Tkinter I've managed to write a little utility that encompasses most of the calculations I've written about in the past.

(I know - most of these calculators are available online already - it's really more of an exercise for me. Somebody may find it useful, though.)

There are both Windows and OSX (Intel only) versions. Feel free to download and/or redistribute all you like. All I ask is if you do redistribute it, please link back to this blog. I'd also appreciate any feedback you might have.


Sunday, June 19, 2011

More on powering LEDs

I've had several questions lately about powering LED spotlights, so I thought I'd see if I can't break it down a little better.

First off, there are 2 ways wire a group of LEDs - series and parallel.

Series: (or what you don't want to do)

In a series circuit, the negative lead of the first LED is connected to the positive lead of the next LED. and so on down the line. In this configuration only 1 resistor is used for the entire circuit. In a series configuration, the number of LEDs you can use is limited by the voltage of your power source. If you have 3 LEDs with 3.6 volt forward voltage wired in series, you couldn't use a 9 volt battery to run them because the total forward voltage is greater than the supply voltage (3.6 + 3.6 + 3.6 = 10.8 volts). I don't recommend this configuration for a few reasons, but mainly because if one point in the circuit fails you'd lose all your lights.

Parallel: (the easy way)

In a parallel circuit each LED has it's own resistor, and the positive leads of all the LEDs + resistors are tied together, and the negative leads are all tied together. When your LEDs are wired this way, the factor that limits the number of LEDs you can use is current (amps).

When you calculate the value for the resistor you need for your LED, one of the values you need for the calculation is the current rating of the LED. If we assume that the calculations are correct, then that current rating is the maximum current that will be flowing through the light. So all we need to do is make sure the total current of all your lights isn't more than your power supply is capable of providing.

So for example, lets say your LED has a current draw of 20 mA. 20 mA (mlliamp) is 20/1000th of an amp, so if you had a 1 watt wall wart, you could run 50 LEDs. I don't recommend loading a power supply to it's full capacity, so I wouldn't run more than about 40 LEDs (80% capacity).

It is possible to wire LEDs in a combination of series and parallel, but I'll go into that another time.

Saturday, June 18, 2011

Method of switching audio between multiple speakers. Also switches spotlight on prop that's "talking".

Friday, February 11, 2011

reversing polarity

(Just needing a place to put an image...)