Saturday, September 19, 2009

Arduino, Vmusic2, XPort -- Halloween Controllers

I've been working on advanced concepts in controlling Halloween displays for a long time. But I've only just started executing some of my concepts last year. The tentacle controller was the first, but it is still very specific to the tentacle. I hope to have a set of fundamental capabilities in every controller and a set specific to the particular exhibit/device.

My microprocessor platform of choice is still the arduino, I'm excited to see the broad range of variations available, especially the Arduino Mega, I need a lot of I/O. The most important feature of my controller concept is that they are networked and can be remotely controlled, configured, tuned, and monitored. That means adding an ethernet interface. I've been experimenting with the Lantronix XPort AR. This device is amazing, so many protocols built-in, including SSH, HTTPS, and email. The built-in web server appears advanced and there are numerous configurable pins. As these devices go, it is on the pricier side (~$65) but you get a lot of features. BUT.... the downside is that you need a software development tool kit to really modify the device for your project. You can drop basic files on the device that the web server will see, but there is some secret sauce in here to have the web server talk to the UARTs and configurable pins. Too bad, it was a promising device but I'm not going to buy the tools. I don't even know how much they cost, you have to talk to salesmen...ick. Come on Lantronix. Give us the razor and we'll buy your blades like crazy. I still haven't decided if I should stick with this device, or just go with a really basic ethernet to serial device like this one. Half the price, but I would have to move some capabilities into the Arduino, like email alerts. In the XPort AR, I can just trigger a pin high which in turn sends an email alert. I have to make this decision soon! Need to get a couple ordered.

The other thing so many Halloween props need is quality sound. I've been searching around for the right method and finally decided on the Vinculum Vmusic2. This is a slick device, a full MP3 player with a serial interface. It has a USB port for a USB fob with MP3s and a 1/8" mini stereo jack for output. Then a set of pins for the serial and power connections. It was frustrating getting it to fire up the first time, the docs are worthless. There is an excellent instructable here on getting this thing set up, but even that didn't point out the key step. Then I found this reference from the Garage of Evil -- fellow high-tech haunters and my problem became clear. By default the Vmusic2 is setup for a CTS/DTR hardware handshake. You can tweak the settings through their firmware editor to just do tx/rx. But I couldn't get the device to come alive, which was required to pull the new firmware from the USB stick. I was beginning to think the default firmware wasn't on the device. Others have alluded to this in numerous posts, which then requires you to jump through hoops with the right cables to talk to the device to flash it. But the trick is to tie CTS to ground, that's it. The device woke up, reflashed itself, and everything is good. I dropped a couple MP3s on a thumbdrive and was soon talking to it through a serial connection firing off music while tweaking the controls. Nice! So in moments I'll be wiring up the first one to the current controller I'm working on. The picture here is the in-progress shot. A chassis from an old Sun outboard SCSI drive (12v and 5V) supply built-in, Arduino, protoshield, several relays, the Vmusic2, and much more to come.

Thursday, September 10, 2009


Last year I borrowed a welder from Donovan, my Halloween fabricating colleague. I had to fab a cart that would be a roving platform for the tentacle. It was a MIG wirefeed welder and even being a complete welding newb, I produced a very functional unit.
From Tangle of Wires
My family got sick of hearing me wax on about the joys of welding and they got me a welder for my birthday. This is a bargain unit from Harbor Freight. We've got a Harbor Freight store close by and while the quality isn't always the best, the price/performance can't be beat. For us seasonal warriors, the gear works well. I started with flux core wire, but my results were pretty ugly. I added a regulator, and a small tank of C25 gas (75% argon, 25% C02) from my local Praxair store. I got a spool of the regular wire as well and now my welds look terrific!! What a difference in weld quality. Now I just need some serious practice. I've only welded ornamental additions on my pumpkin hanging shepards hooks so far this year, but plan to get more use fabricating various odds and ends.
From Tangle of Wires

'Tis the Season...

Halloween is coming up quickly and I've been negligent in posting any new blog entries for a long time. My plan is to do the Woodland Park Zoo Pumpkin Prowl Event again this year, at least if we can work through the insurance requirements for us wee vendors at the zoo. Liability insurance for events is 'spensive to say the least. And it appears hard to get a policy tailored to my situation. Getting quotes now from the various providers that do coverage for Halloween events -- stay tuned.

Not sure it there will be any new biggies this year, so many details still to do in the existing props. The witch will get some new features, she is still too static right now. I'm hoping to add a new Pumpkin Fountain controller that will still interface with the Zoo's Z-Play control system, but allow me direct access and control and tuning as well. Also it will be easier to monitor what is happening with it. Ethernet interface, arduino controller, and vmusic2 sound. Options for triggers and remote manual control, test modes for setting the sensors, and manual control of the duty cycle. Also control of the lights, fountain pump and compressor too. Web interface, hoping for syslog for logging, email out for alerts (low water, low air pressure, etc.) and more. We'll see how far I get. Can't seem to find any good pictures of the Pumpkin Fountain at the moment, the picture here is just after setup, but before the pumpkins were on it.