Halloween costume

[lordnacho]

My son(3 1/2) wanted to be a ghost for halloween, so I suggested a Pac Man ghost.  Now he wants to be Pac Man. 
While I don't have much time to work on it, I can't turn this down.  I snagged a couple used foam posterboard from work, so I cut some circles out of.  Have to get some felt this weekend.  Will be making a ghost costume for my daugher(20 mos), pink I guess or maybe blue cause she does like to bite my son

So was thinking how I can integrate some Pac Man sounds.  I have a couple old iPhones I could attach.  Was looking at the iPhone SDK last night to make a quick app.  A couple buttons or something and play sounds.  I'm a developer so I thought it would be easy to crank something out, but looks like I have to read about it.  Running low on time, so I'm looking for any other suggestions.

[yaksplat]

Why not take some soundbytes and merge them into an mp3 with some gaps just to create some random timings?

not controllable, but it'll get the same point across.

[ChadTower]

Battery powered speakers, make an mp3 of about 45 seconds of Pac sounds, and play it looping.  You don't need special controls or anything.  I have done this before for a few costumes.  The reality is that trick or treating only brings you into contact with most people for a minute or two.  After that some other kid comes up and they forget they even saw yours. 

Yaksplat's idea is good, too, if you want the sound to not be continuous.  A constant Pac loop might get annoying to the people walking around with you.

BTW, I made my son a Pac costume when he was small.  It was actually a cardboard box that I had cut the corners off to make round.  I covered it in yellow construction paper for the Pac and black paper for the mouth.  It looked really good but the kid had trouble walking on stairs because he couldn't see down over the front of the box.  I imagine if he fell, it might have been ugly, because he might have rolled away down the stairs.   

[lordnacho]

Thanks, mp3 sounds like a good idea.  Any sort of interactivty and the phone would have to be visible and the kids may pummel him trying to touch the buttons.  Buttons to kids are like brains to zombies.  May skip on the speakers though, as he may not be able to lug them around too far(I won't be there for his daycare parade).

Not sure we'll actually go trick or treating, maybe a few neighbors that we know.  We live in NYC, works a little different here.  In the burbs you can tell who welcomes the kids.  We do get some trick or treaters, but we do hang up stuff on our apt door. 
Instead there's a party in the center of the complex and they'll be worn out from that the games and stuff.   Mostly elevators here, so don't have to worry too much about them rolling down stairs

[ChadTower]

You could mount the phone inside the costume so that only your kid has access to it.  I did that the year I made my son a Speak and Spell costume.  Inside the box had a backpack on with speakers in it.  There was a real Speak and Spell mounted on the inside of the box so he could press any buttons he wanted.  The speakers were LOUD, too.  People loved it. 

[lordnacho]

Heh sounds like a cool costume.

Trying to keep the costume small, so he can still run around.  If it's too bulky he'll just want out of it, so he can run around with his friends.  So I think his head and arms will be outside of the costume.  Actually mounted inside or out, he probably wouldn't be able to see and touch it at the same time.  I'll tinker with that corded remote/headphones, if I can find it.

[ChadTower]

Running around is a key requirement.  If you make the hole in the box big enough, though, he can pull his arms in and out without any issues.  Put a yellow shirt/coat on him inside the box and nobody will notice if the hole is big.

[lordnacho]

Good point. 

I was trying to see how it would look on him, but he wouldn't keep still.  So I resorted to a photoshop mockup, found a silhouetteof a kid, much easier.

[ChadTower]

Hahaha.  I had that problem exactly once with my older son.  He wouldn't be bothered to help me with his costume.  So I went to the store and got a cheerleader outfit and told him his choices were to help me make his costume or be a cheerleader. 

He helped me make his costume without a complaint from then on.   

[lordnacho]

That's pretty good.
Would be scary if they were ok with that costume...not that there's anything wrong with it

[ChadTower]

It was a risky gambit for sure.   

[Well Fed Games]

My son(3 1/2) wanted to be a ghost for halloween, so I suggested a Pac Man ghost.  Now he wants to be Pac Man. 

No kidding, when we asked my daughter (she was about 3 1/2 at the time) what she wanted to be for Halloween, she said "pac man ghost"... so we will be walking around the neighborhood with colored ponchos with eyes made out of adhesive felt on them. She makes me so proud!

[SavannahLion]

Heh, my 5 yr old will be a SW character for 4 out of 5 years. This year, he's Vader.

But I digress, just an idea.... Does the iPhone not have accelerometer? When my kid was three, one pixie stix and he went from 0 to 3 blocks in as many seconds. Took four other kids and myself to corral him.

[lordnacho]

No kidding, when we asked my daughter (she was about 3 1/2 at the time) what she wanted to be for Halloween, she said "pac man ghost"... so we will be walking around the neighborhood with colored ponchos with eyes made out of adhesive felt on them. She makes me so proud!

What color(post power pellet blue or one of the pre-colors)?  Going pink for my daughter

Heh, my 5 yr old will be a SW character for 4 out of 5 years. This year, he's Vader.

But I digress, just an idea.... Does the iPhone not have accelerometer? When my kid was three, one pixie stix and he went from 0 to 3 blocks in as many seconds. Took four other kids and myself to corral him.

Going Vader will be another proud moment. 

Heh sounds about right.  Like Rocky trying to catch the chicken

[Well Fed Games]

No kidding, when we asked my daughter (she was about 3 1/2 at the time) what she wanted to be for Halloween, she said "pac man ghost"... so we will be walking around the neighborhood with colored ponchos with eyes made out of adhesive felt on them. She makes me so proud!

What color(post power pellet blue or one of the pre-colors)?  Going pink for my daughter

Well the colors were pretty much decided on by what Amazon had in stock  , so we got a pink and an orange and a blue- the blue will get a squiggly mouth for post power pellet.

[Mysterioii]

If you had a little more time to prepare I'd suggest an arduino plus a "wave shield" from adafruit.  You'd have to do some coding...  the wave shield plays audio clips off an SD card and you could hook up buttons to selectively trigger whatever audio clip you wanted.  You'd have to add a small speaker and a battery.

Would take a bit of DIY and a little time to pull it together, but definitely doable.

[ChadTower]

Hold on.  How would you set up the individual switch lines?  I have been poking around an idea similar to that for a different purpose.

[Mysterioii]

Pretty easily really.  The arduino has several GPIO pins....  you'd just need to define some as inputs then wire some pushbuttons to them....  your wire runs could be pretty long and it wouldn't hurt anything, if you wanted to put the pushbuttons on his belt or something.  I would just put a pulldown resistor to ground on each input pin to keep them from floating, then connect one side of each momentary pushbutton to +5v and the other to an input.

Because of the pulldown resistors to ground you'll get a nice clean ground on each input when you don't press a button (otherwise they'd float and you might get some false positives).  Then your code just needs to loop forever and constantly check the inputs.  If you see a high, tell the wave shield to play the appropriate sound, then start checking for high inputs again.

[ChadTower]

That could work.  Thanks, man.  That's pretty much at the edge of my current skills with this stuff.

[lordnacho]

Oh man I wish I had the time to do this. 

[SavannahLion]

Pretty easily really.  The arduino has several GPIO pins....  you'd just need to define some as inputs then wire some pushbuttons to them....  your wire runs could be pretty long and it wouldn't hurt anything, if you wanted to put the pushbuttons on his belt or something.  I would just put a pulldown resistor to ground on each input pin to keep them from floating, then connect one side of each momentary pushbutton to +5v and the other to an input.

Because of the pulldown resistors to ground you'll get a nice clean ground on each input when you don't press a button (otherwise they'd float and you might get some false positives).  Then your code just needs to loop forever and constantly check the inputs.  If you see a high, tell the wave shield to play the appropriate sound, then start checking for high inputs again.

OK....

To begin with. Wave shield from ADA is very very nice and it saves a lot of soldering so for anyone who doesn't know or care to solder, go get it. However.....

If you're good, you have basic soldering skills and you know how to port code, look for the AVR335 (this is the one I'm referencing) document or check out http://elm-chan.org/he_a_e.html or http://avrpcm.blogspot.in/ for alternative solutions (read: cheaper). Just don't wire the I/O pin directly from the AVR to the speaker. Fine for testing, but you'll burn it out in the long run.

Second...
Don't use pull down resistors. The AVR doesn't need to read buttons that way. The AVR's (Arduino's included) have built-in pull-ups. Use them and save yourself some soldering. It's even outlined in one of the manufacturers docs. Set the desired port(s) for INPUT then activate the PULLUPs for whatever pins you need.

Finally, contrary to what some... experts might tell you. This isn't going to hurt the AVR. You don't need resistors in series. If you want to know what the ohmage is it's squirreled away in the individual controller's docs. But unless you're doing some funky stuff, it's not really crucial in this kind of application. Remember, set to INPUT then switch on the pull-ups. The specific steps are, again, detailed in the docs.

I have copies of the docs squirreled away on my laptop, if you're jonesing for the file names, I can see if I can dig around and find them. I probably accumulated about 50 or so docs related to the AVR lines.

But I digress. The technique I describe is the exact same method that both Andy's and Randy's products use to read arcade buttons. So, wiring everything up is no different. Common ground, each switch gets their own IO.

If you want to get fancy and start using matrix's or whatever. Arduino has libraries that handle those as well OR you can search around for what kind of heavy lifting that involves. My preference is to use C or ASM instead of the Arduino libraries. Mostly because I don't feel like shelling out $100 or more for a bunch of shields when I can tear apart what's in my scrap bin and pay only $15 or so for an AVR board (I purchased one that's Arduino compatible similar to a Teensie).

[Mysterioii]

A thousand pardons good sir, I don't have an arduino in front of me and I was typing that up 10 minutes before I had to leave so I failed to fact check.  The last thing I worked on used an I2C GPIO expander that did not have any built-in pullup or pulldown resistors so I had to handle it myself to avoid floating inputs.  When rolling my own I prefer to pulldown inputs to ground then switch high, because to me 'high' = 'on', but yes, if you've got pullups built into the device then definitely use them then switch ground to the pins to keep it simple.

I don't think I anywhere implied that anything would damage the device?  In the absence of built in pullups, which I forgot about, then the pulldowns are just to ensure that there is a ground at the pin when you're not pressing the switch at that input.  Otherwise you'd get a floating input, which could give you some false readings.  It's not damaging at all, it's just not clean and can lead to undesired behavior.  You don't need both pullups and pulldowns simultaneously, I agree.  But you need one or the other.

To begin with. Wave shield from ADA is very very nice and it saves a lot of soldering so for anyone who doesn't know or care to solder, go get it.

The wave shield is available only as a kit, so it doesn't save you all that much soldering really.  It's an easy to assemble kit though, and they walk you through it very well on the web page.

https://www.adafruit.com/products/94

It sounds like the arduino environment didn't support enabling the internal pullups directly until recently?  The very most recent release actually.  True you don't have to program AVRs using the arduino interface, but for a beginner it makes it very easy to get started.

As of Arduino 1.0.1, it is possible to enable the internal pullup resistors with the mode INPUT_PULLUP.  Additionally, the INPUT mode explicitly disables the internal pullups.

The code you linked to about playing sounds directly from the AVR is cool, however it looks like you have to actually store the audio as program memory in the code itself.  That's fine if you don't mind re-encoding the audio and recompiling then reprogramming your controller every time you want to change the sound clip.  You're also limited to the memory space within the controller (you could of course interface with external memory, but that's outside the scope of the example).  The wave shield reads files off an SD card, no need to recompile or reprogram anything if you just want to swap some sounds out.  You're not limited to program memory space, it's got a volume thumbwheel, headphone jack etc.  It also uses a real DAC instead of trying to approximate things using the PWM outputs.

As always, there's more than one way to skin a cat, use whatever meets your needs.     There's "cheaper" and there's "beginner friendly".  If someone without much electronics experience is trying to throw together a costume for their kid two weeks before Halloween I'd spend a few more bucks and go for the easier implementation.

Mostly because I don't feel like shelling out $100 or more for a bunch of shields when I can tear apart what's in my scrap bin and pay only $15 or so for an AVR board (I purchased one that's Arduino compatible similar to a Teensie).

Yes I agree with you...  not everyone has the time to do that though, nor the expertise to know where to begin.  The arduino is a gateway drug for hobby electronics, it's not suited for everything, but it's a good way for people to get their foot in the door.  There's a large established community, example code all over the place for just about anything.  It's a good place to start...  I also have some Teensy boards... the guy just released an ARM version, Teensy 3.0.  He just finished up a kickstarter for it, I got some for about $19.  Regular price will be a bit higher than that I believe.

One more note... the wave shield is apparently not pin compatible with the arduino leonardo version... so if you get one, either use it with an older arduino model or be prepared to clip a couple of pins and do some rewiring.

[SavannahLion]

My apologies if it sounded like I was getting on you about damaging the AVR via the pullups. That's in reference to a different thread where I brought that up and was pounced on by a different member. At the time I couldn't articulate the logic behind it. After working with my selected AVR, I can now.

The Wave is kit only? I missed that blurb. I saw the $20 price tag for something I'm already halfway through and didn't read much further into it. Well, i stand corrected.

I wasn't aware that Arduino didn't allow support of the internal pullups until recently. Another annoyance from a substandard language everyone keeps humping. As far as I know, the Arduino was always on the AVR platform until recently and Atmel's introduction of internal pullups pre-date Arduino's creation.

I have never liked how the Arduino handles the ports. It's borderline absurd to enforce dynamic pin assignments for a microcontroller when those assignments could be done at the compiler. I see why it was done, it's just a massive waste of resources. It appears I'm not the only one that feels that way as I see a lot of people shift down to direct pin handling.


Apologies out of the way....

I had a hard time dealing with the concept of 0==on until I realized how easy it was to handle the states within ASM. Most of the time, I was looking for a change in state, not whether it was on or off.  Using pulldowns is valid, just not the sensible thing to do with the AVR series.

Whoops, I thought I included a link that outlines how to use an SD card of your own. I know the AVR335 doc uses a bit of memory via SPI which should easily be adaptable to any other serial memory.

However, the link where you compile in the audio shouldn't be ignored. This one allows audio using the absolute minimum amount of hardware. Using this project as a base gives you a way to test construction of a speaker setup without going through the headache of getting a bit of memory expansion working correctly. In any case, if you look around, you'll find the .wav file is just a contaimer format that adds a lot of fat and overhead to a microcontroller. Why have stereo when you only have one speaker? Make it mono, set a standard bit rate, strip the container and voila! Anyone who can write C and solder should have enough skills to pull that off. Hell, I actually found it easier to do the audio files. It was a lot harder to work out which of the registers I needed to set to get PWM going.

[Mysterioii]

No problem man, and sorry if I got a bit defensive.  It sounds like you truly have worked with AVRs more than I have so I give you props.  My background is EE but I have been out of the field for like 10 years and only recently have been making an effort to get back into things, but the field has evolved and I'm quite a bit behind the curve, and thus I came back into things at the hobby electronics level and am building back up from there.  Lots of cobwebs regarding uC's that I am still shaking out of my head.

I like the arduino for what it is...  a good introduction.  I build a water monitor system for my home with an arduino and an ethernet shield that I talked about in another thread...  monitors a bunch of water sensors, tilt switches on a sewage shutoff valve, disconnects power to a sewage ejector pump when the valve is closed, has a warning buzzer, LED indicators on the device and by the front door to alert you to the status...  It serves up a web page so you can check the status of all the sensors from anywhere in the world, and will send me an email/text whenever a critical status is detected (ie. water in my basement).  It does other stuff too, but I won't bog things down here.  The code compiles down to 19K, I'm fairly proud of it, I think I got the most out of the arduino there.  Going forward I won't feel constrained to sticking with the arduino platform, but it was a nice way to get back into things.  And if you ever need to do something basic really quick, like blink some LEDs, it's a pretty quick way to make it happen.

One thing I like about the community is that it's mostly open source, so you can see the schematics for the arduinos and most of the shields themselves.  For my next big project I'd like to try my hand at PCB design (rather than prototyping on perfboard and wirewrapping a ton of stuff), and having a bunch of open source shield designs would help one cannibalize the designs and pull everything of interest together into one custom board.

Anyhoo, yeah there are different approaches.  It actually irks me a bit that they just now included the ability to use the internal pullups...  I'd have to go back and check my monitor system design but since I did it on their platform and thus couldn't enable the internal ones at the time I bet I did use some external pullups or pulldowns (actually I really think I used that I2C GPIO chip for most inputs and only used the arduino pins for outputs, so it was a non-issue there).

[SavannahLion]

Now I remember your name. I saw that discussion. Gave you props IIRC.

That's the kind of project that deserves a writeup, not that constant stream of ---smurfy--- "look at me I can turn an led on" that keeps cropping up all over the place.

[yaksplat]

i wish i knew more about circuits.  I had a few circuits classes in ME and CS. but i'm more along the line of home much can you put on that beam and i'll write a program to prove it

I like seeing the stuff on here to try and learn more.  Keep up the good work!

[Ed_McCarron]

Finished my son's today.

[SavannahLion]

My wife discovered the Vader costume was mismarked as the wrong size and the store didn't have anymore in the right size. I almost panicked when he went for a crappy vampire costume from that crappy teen film, whatsits name. Until he saw Jengo Fett. Not as cool as Vader but still Star Wars. I don't think he cares all that much about the suit really. Big mask, big gun, forget the crap vampires.