Saturday, August 7, 2010

SAM


Working together with our intern, the Sound Amplitude Measurement device was made. Guts include a PIC16F873A, servo motor for the dial, active filter at 1.5Hz based on an opamp and RGB lighting inside the head. This is the first thing I've ever had to stuff (%100 polyester fiberfill) and I found it oddly soothing to staple swathes of puffy stuff to the MDF framework inside.

Monday, July 26, 2010

Pneuman update

Working on this when I can, Pneuman's controller has been upgraded from a chunky old PC with a synchronous serial connection to an Arduino (OMG Arduino!!!). A WiFly shield communicates with the user interface (a PC kiosk somewhere) and a 6-channel Darlington driver board fires the solenoid valves to pump his legs. Three analog inputs are used to capture the values from optical pickups aimed at a 3-bit grey-code encoder wheel fixed to the cranks of the bike. This gives a starting position for the uC to pedal from. Two digital inputs are used for the front and back travel limit switches.

Transportation game upgrade

This was originally a roll-a-ball game from Bob's Space Racers. It was modified in early 2000 to teach people about energy consumption and different options for transit. Electrical modifications included automating the need for an attendant and adding sound effects. While the mechanical and cabinetry changes were solid, the electronics mod was undertaken by a muppet who did a terrible job. Over 100 relays were wired together with a mass of unlabeled cable, poorly crimped connectors and live 110VAC....

...euch. Reliability was terrible and troubleshooting the problem even worse. So, in February 2010 I gutted it and installed a totally new control system.It's based on a PLC from Automation Direct, a CFSound III card and some relays to switch the larger loads. The control system was mounted on a grounded sheet of aluminium and enclosed to keep the dust away. It's been running for several months now with way better uptime. One great addition was a watchdog timer to reset the game if someone walks away before finishing the race. Having the PLC on the network means I get emails when customer service staff hit the reset button, a good indicator of trouble if there's more then a couple messages per day.

This is one track and carriage assembly that advances the characters and makes them rock. As the chain is rotated around the gearmotor and idler sprockets the carriage is pulled along. A sprocket mounted in the carriage has the return-chain passing across it and rocks the character back and forth with an offset cam. This part of the game still has problems as people sometimes throw the ball into the tracks instead of rolling it up the play surface. I have yet to find a good solution to this short of covering all the tracks with plexiglass...

UFO Upgrade


This UFO was created several years ago as a TV show prop but had hella flaky electronics that were dead when I found them. I've since upgraded it with a PLC from Automation Direct, some chasing rope lights around the outside, underbody lighting and sound effects.

Sunday, March 28, 2010

A button box!

Ak, so it's been ages since the last post but I've been busy. Recently finished was a one-day project to control a Sanyo projector. Operation of the projector can be controlled via ASCII commands over RS-232. A more robust remote than the consumerish plastic thing was needed and so the button box came into being. Boasting a mighty PIC16F873A-04, a case recycled from an old KVM switch and three of the best buttons I've ever found, the thing kicks ass at it's (fantastically simple) job (Power on/off, shutter open/close). On to the next project....

Saturday, January 23, 2010

Vacuum + Powertool foot switch

Work has been crazy lately and I haven't been spending as much time on my own projects as I'd like to. I finally got around to getting my Dremel tool and shop vac controlled with a foot switch. As I typically use the Dremel with a drill press attachment this is going to be a boon.

Wednesday, January 20, 2010

Sick

I was sick today and slept in till '3, after waking and feeling marginally better I attempted all the standard sick-person stuff but was quickly bored (TV, a good book, staring out the window at people). I decided to play around with an Arduino, Wiznet W5100 ethernet shield and some temperature / RH sensors. This is the result and here's the link. The other board is a stepper driver that was used for testing some motors destined for a reprap.