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[ ENDED ] Oct 2013 - 43oh Halloween Contest

2013 43oh Halloween Contest  

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Win a TI Sensor Tag Development Kit!


Entry to the Oct - 2013 Halloween contest is open. This is an opportunity for you to show off what you can do with the MSP430 to spook someone. Last date for entries is 31th October, 2013. 


Some cool 43oh Halloween Projects:

Halloween Motion Triggered Sound and Light Thingamajig

Iron Man Halloween project

http://www.43oh.com/2011/10/halloween-special-zombie-in-a-can/'>Halloween Special

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In my country we don't celebrate Halloween (nor Dia de los Muertos, just in case someone asks ;) )... The only scary thing I can think of is feeding a launchpad straight off the 240V mains without isolation transformers... if that is not scary, I don't know what can be :D


Enjoy the contest all of you that have fun on 31th October !


P.D.: No, I'm not suggesting anyone to do something so unsafe as feeding any circuit off mains without the proper isolation. And/or the proper knowledge. If you don't know what I am talking about... *just don't do it*. You can die while trying.

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I didn't actually see this contest until I had already posted on the forum. My project is exceedingly lame. Yes this is as far as I have got with ARM microcontrollers: I can successfully plug in a Tiva Launchpad, and put it inside a pumpkin. The immediate rationale for doing so was trying out a USB adapter that I got as a freebie. Oh, and to entertain the kids for 5 seconds or so.  :smile:





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Took the challenge. Started monday when I got home from work.


Project is spooky eyes for the bushes. 8 channels, each of which will drive approx 3 amps, which is abou 110LEDs from the the 12V LED strip I used.


Cut the strip into three LED sections (the minimum for this type), soldered on 300mm lead sets (twisted pair from cat5 cable), and used epocy to ttach the leds to ping pong balls. bent the strip so the LEDs fit flush to the surface. The epoxy provides good coupling, so, before painting, the balls had a good bright red glow.


Masked pupils and painted the balls black with the cheapest spray I had on hand. Several coats to block waster light. The LEDs leak a lot to the side.


Threw the code together in about an hour. Three modes.


Interesting part of the code is the method for not caring about the timing. It dosen't much matter if a PWM tick is missed the start of the cycle, as if the LED is off, it stays off. If it is on, it makes dimmest setting one tick brighter. Therefore, I put the whole mess into the interrupt routine and counted the PWM myself, rather than use the timer features, so that I could run 8 PWM's off one interrupt with several modes. The trick is to build the NEXT PWM state during the tick, and set the outputs first thing on the interrupt. Also, only do the work for the PWM pulse length once per cycle, which may lengthen the first tick, but it will be consistant and not mess up the overall appearance in operation. Could've upped the clock to buy more cycles, but it won't look any better. for the uploaded program, the first tick of the cycle, when the updates are done, just misses over-running. If all outputs were set to mode 2 (more conditions), I think it does, but it looks fine in practice.


I used P2 for output so I could use the launchpad LEDs during testing, and was going to use the other pins for input to change modes. I got lazy. May do it later.


The drivers are TIP31's to ground. Simple, and I had them in the stockpile. Mounted on a scrap of vectorboard from an old S100 bus A/D from when I was working in the medical lab.


Pics are the eyeballs hanging to dry; channel schematic; shot of the launchpad, channel drivers (second piece not yet mounted), terminal strip, and power supply liberated from an old external hard drive that powers the mess; a couple shots of the eyes in the shrubs; code; and link to video of operation will follow when I upload it (youtube accound came from the Google+ name I got when I bought a nook. Didn't habe one, and the doofus at B&N made it for me without telling me without telling me. As you will see, he was quite creative in making up a name, seeing as how he had mine in front of him, as well as me standing there) The eyes are not visible, once twilight hits, unless they are on, nor are the twisted pairs from the cat5.


Video link will be posted when I get done with youtube. BTW: schematic not bad for MSpaint, no? Don't have good schematic software on this machine...


EDIT: link to video:


EDIT 2: revised code is attached as main-revised. Moved text of followup here. Left original main as I can not bury my sins in good conscience



Found an hour and made the code a bit more presentable.


Function control is in the main, and only the PWM setup is in the interupt routine. Also, bushbutton on launchpad acts as circuit test: Pushing it turns all channels on (well, mostly. The PWM interrup my shut off a channel for the duration of the interrupt routine) for checking the wireup.


Also, modified the structure for each function to allow a bit more user tuning: The length of each operation can be varied for each channel.


I didn't put the processor to sleep when the updates are completed. A few hundred microwatts for the processor when the LED's are using 10 or more watts (max without modification to code or hardare is about 250W) isn't really significant.\


This update is not really any more elegant than the original, but it is structured better.... I am less embarrassed by the code now.









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Forgot two things:


Modes: on with occasional blink, fade in fade out, and hard on hard off.


Also, used phone crimps for connections  (pic attached).... real handy, but only good for a few hundred mA


edit: third thing: eyeballs are epoxied in pairs to 12Ga bare wire to hold position. A little black paint and not visible. Used liquid electrical tape (again, black) to coat exposed joints. The crimps are watertight.


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