Sunday, October 25, 2009
Thursday, October 15, 2009
now that's a big cauldron
Saw this on my way home from work tonite. Not sure what it's made, but dang it's cool!
Tuesday, October 6, 2009
the porcupine
OK, here it is. 5 inputs, 16 switched outputs, & 3, 5, & 12 volt power taps. I'm not going to give a step by step how-to because for as wild as it looks, it's really pretty simple.
The TTL signal from the parallel port pins travel through the small gauge wire to the circuit board, through the 1k resistor, and to the base pin of the transistor. The emitter of the transistor is connected to ground. The collector of the transistor connects to one side of the relay coil, & the other side of the coil connects to +12 volts. There's a diode across the coil of the relay, with the stripe toward the side connected to +12 volts. When VSA activates the pin the transistor allows current to pass from the collector to the emitter, completing the circuit and triggering the relay.
The inputs for MonkeyBasic's Helmsman, pins 10, 11, 12, 13, 15, & ground, are brought out to the barrier strip on one end of the enclosure. The other end of the enclosure has ground and power pins fed by a PC power supply, connected through a hacked PC power supply extension.
That's pretty much it. Now all I have to do is design my yard display & decide what to control. Shouldn't be a problem - I've got two whole weeks...
Sunday, September 20, 2009
power again
OK, so I modified a PC power supply to power my yard display. Plan was to use it with the parallel port relay controller I'm building (and yes, I really am building it.) So anyway, I modified it & it worked. Then, I decided to use it to show my wife how the LED spotlights would look lighting up a tombstone. Like a dummy, I just twisted the wires together & left them uninsulated. Of course, I was careless and shorted the 12V lead to the case of the power supply & let the magic smoke out of it. I was kinda bummed, but lesson learned.
Anyway, I was perusing the interwebs the other day & came across a pretty neat idea. Why cut up a perfectly good power supply when all the wires you need terminate in the main connector? Why not build a breakout box with a switch and taps for the all the voltages? Tell me, why not? I've lost the link to the page I found the idea on, so I'll show how I built mine.
here's what I started with. A small project box from Radio Shack, 3 red binding posts, 1 black binding post, 4 ring terminals, the switch from my dearly departed hacked power supply, and an ATX power supply extension cable.
I started by drilling 4 holes evenly spaced on the bottom of the project box
Then I cut the male end off the extension cable and drilled a hole in the end of the project box just big enough for the wires to pass through.
Next I put the binding posts in.
I drilled a hole for the switch in the side of the box, making sure to position it so the terminals would clear the binding posts.
Things got a little less simple here. The wire colors on the ATX extension weren't the same as the standard colors on the power supply (couldn't find one online that was), so I plugged it into a power supply so I could match up the colors.
Then, it was just a matter of connecting the switch lead & a ground to the switch, and the ground, 3.3V, 5v, and 12V leads to the binding posts. I ran the extra leads into the box just to keep things neat.
It works!
This should be handy. I'll use it for bench power as well as power for my yard display.
Anyway, I was perusing the interwebs the other day & came across a pretty neat idea. Why cut up a perfectly good power supply when all the wires you need terminate in the main connector? Why not build a breakout box with a switch and taps for the all the voltages? Tell me, why not? I've lost the link to the page I found the idea on, so I'll show how I built mine.
here's what I started with. A small project box from Radio Shack, 3 red binding posts, 1 black binding post, 4 ring terminals, the switch from my dearly departed hacked power supply, and an ATX power supply extension cable.
I started by drilling 4 holes evenly spaced on the bottom of the project box
Then I cut the male end off the extension cable and drilled a hole in the end of the project box just big enough for the wires to pass through.
Next I put the binding posts in.
I drilled a hole for the switch in the side of the box, making sure to position it so the terminals would clear the binding posts.
Things got a little less simple here. The wire colors on the ATX extension weren't the same as the standard colors on the power supply (couldn't find one online that was), so I plugged it into a power supply so I could match up the colors.
Then, it was just a matter of connecting the switch lead & a ground to the switch, and the ground, 3.3V, 5v, and 12V leads to the binding posts. I ran the extra leads into the box just to keep things neat.
It works!
This should be handy. I'll use it for bench power as well as power for my yard display.
Saturday, September 12, 2009
Sunday, September 6, 2009
Sunday, August 30, 2009
A little info...
...on the controller I'm going to build.
Like I said before, I plan to control all the elements of my haunt with Brookshire software's Visual Show Automation (VSA) software. VSA's a pretty amazing piece of software, able to control all sorts of hardware interfaces. One of those interfaces is a parallel port relay board, more commonly known as a kit 74. I plan to build a version of this controller, (2 of them in one enclosure, actually) with one slight modification.
Hauntforum member Monkeybasic has written a really cool add on for VSA called Helmsman. Helmsman lets you create playlists of VSA routines and .mp3 or .wav files, control the volume of each routine or sound file individually, control the relays of a kit 74, and most importantly for my application, provides external triggers through the parallel port. And best of all, it's free! My relay controller will have terminals exposed for the triggers. If you don't have a need for the triggers, I'd recommend saving yourself the headache and just buy the kit 74. I'm building mine because I have most of the parts on hand, and I'm a glutton for punishment.
The way the parallel port relay board works is really pretty simple. Pins 2 - 9 of the port are the data pins, D-0 to D-9. When VSA tells relay 1 to turn on, what it's really doing is telling the computer to send 5 volts to pin 2 of the parallel port. So all we have to do is use that 5 volts to trigger a relay. Simple, right? Well, almost. The parallel port can't provide enough current to trigger a relay and it's pretty sensitive to power spikes and shorts, so we need to give it a little protection.
To do this, we'll use a transistor. Transistors are cool. (I think I'll have that printed on a t-shirt - I'm proud of my geekiness.) A transistor works like a switch. When you apply a small amount of current to one pin, it allows a larger amount of current to pass between the other two pins.
The transistor I'll use is a 2n-2222 switching transistor. You can pick up a pack of 15 at Radio Schmuck for less than $3. The pin configuration is shown above. The middle pin is called the base. When you apply 5 volts from the parallel port to the base, it allows enough current to flow from the top pin (called the collector) to the bottom pin (the emitter) to trigger the relay.
Just to be on the safe side, I'll place a 1k resistor between the parallel port and the base of the transistor, to limit the current flow to the transistor and help protect the parallel port.
With the transistor handling the current, I can add in the relay. The relay is just a switch that uses an electromagnet to turn it on and a spring to turn it off. When you apply power to the coil of the relay - in my case 12 volts - it triggers the relay. So it's just a matter of connecting one side of the coil to a 12 volt power source, the other side of the coil to the collector of the transistor, and the emitter of the transistor to ground.
Sounds simple enough, and it would work if I stopped right there. But there's one more area that could potentially cause a problem, and it's not at all obvious. Put your propeller beanie on, cause this is gonna get a little geeky. When you pass an electrical current through a coil of wire a magnetic field is generated. That's how the relay works - the current turns the coil in the relay into an electromagnet which in turn pulls the contacts closed. But - here's the part that's not obvious - when the current is removed from the coil, the magnetic field collapses and creates a spike in voltage. This spike can be as much as 200 volts, which would wreak havoc on our poor transistors and computer port. So, I'll need to give that nasty energy spike some place to go. I'll do that with a diode.
A diode is a nifty little piece of hardware that kind of acts like a one way valve for electrical current. What I'll do is place a diode across the coil of the relay in such a way that it won't interfere with the normal operation of the relay, but will give the spike (called back EMF) a place to go once the parallel port tells the transistor to stop passing current.
That pretty much covers the basics. Just build, rinse, repeat. I'll get some pics of the actual build as soon as I actually build it.
Like I said before, I plan to control all the elements of my haunt with Brookshire software's Visual Show Automation (VSA) software. VSA's a pretty amazing piece of software, able to control all sorts of hardware interfaces. One of those interfaces is a parallel port relay board, more commonly known as a kit 74. I plan to build a version of this controller, (2 of them in one enclosure, actually) with one slight modification.
Hauntforum member Monkeybasic has written a really cool add on for VSA called Helmsman. Helmsman lets you create playlists of VSA routines and .mp3 or .wav files, control the volume of each routine or sound file individually, control the relays of a kit 74, and most importantly for my application, provides external triggers through the parallel port. And best of all, it's free! My relay controller will have terminals exposed for the triggers. If you don't have a need for the triggers, I'd recommend saving yourself the headache and just buy the kit 74. I'm building mine because I have most of the parts on hand, and I'm a glutton for punishment.
The way the parallel port relay board works is really pretty simple. Pins 2 - 9 of the port are the data pins, D-0 to D-9. When VSA tells relay 1 to turn on, what it's really doing is telling the computer to send 5 volts to pin 2 of the parallel port. So all we have to do is use that 5 volts to trigger a relay. Simple, right? Well, almost. The parallel port can't provide enough current to trigger a relay and it's pretty sensitive to power spikes and shorts, so we need to give it a little protection.
To do this, we'll use a transistor. Transistors are cool. (I think I'll have that printed on a t-shirt - I'm proud of my geekiness.) A transistor works like a switch. When you apply a small amount of current to one pin, it allows a larger amount of current to pass between the other two pins.
The transistor I'll use is a 2n-2222 switching transistor. You can pick up a pack of 15 at Radio Schmuck for less than $3. The pin configuration is shown above. The middle pin is called the base. When you apply 5 volts from the parallel port to the base, it allows enough current to flow from the top pin (called the collector) to the bottom pin (the emitter) to trigger the relay.
Just to be on the safe side, I'll place a 1k resistor between the parallel port and the base of the transistor, to limit the current flow to the transistor and help protect the parallel port.
With the transistor handling the current, I can add in the relay. The relay is just a switch that uses an electromagnet to turn it on and a spring to turn it off. When you apply power to the coil of the relay - in my case 12 volts - it triggers the relay. So it's just a matter of connecting one side of the coil to a 12 volt power source, the other side of the coil to the collector of the transistor, and the emitter of the transistor to ground.
Sounds simple enough, and it would work if I stopped right there. But there's one more area that could potentially cause a problem, and it's not at all obvious. Put your propeller beanie on, cause this is gonna get a little geeky. When you pass an electrical current through a coil of wire a magnetic field is generated. That's how the relay works - the current turns the coil in the relay into an electromagnet which in turn pulls the contacts closed. But - here's the part that's not obvious - when the current is removed from the coil, the magnetic field collapses and creates a spike in voltage. This spike can be as much as 200 volts, which would wreak havoc on our poor transistors and computer port. So, I'll need to give that nasty energy spike some place to go. I'll do that with a diode.
A diode is a nifty little piece of hardware that kind of acts like a one way valve for electrical current. What I'll do is place a diode across the coil of the relay in such a way that it won't interfere with the normal operation of the relay, but will give the spike (called back EMF) a place to go once the parallel port tells the transistor to stop passing current.
That pretty much covers the basics. Just build, rinse, repeat. I'll get some pics of the actual build as soon as I actually build it.
Subscribe to:
Comments (Atom)
