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Project: The High-Lighter
Date:April 2006

Summary:

The High-Lighter is a trampoline based flame effect. The installation involves a volunteer from the audience jumping on a unmodified trampoline. An ultrasonic sensor placed below the trampoline measures the changes in the height of the trampoline canvas as the user jumps up and down. A microcontroller notes the changes reported by the sensor and triggers a single solenoid valve to open and close. Based upon on the amount of force being applied to the trampoline the solenoid valve will behave differently. The harder someone jumps on a trampoline the longer the solenoid valve will stay open producing a reasonably sized fire ball. LP-Gas will be released through the solenoid valve while it is open and ignited by a nearby pilot light covered in steel wool. A RFID reader is included used to prevent the trampoline from being used without proper authority present.

Video:

Images:

Random Facts:

This project took about six weeks to fabricate and test. It is a total misuse of common backyard items such as trampolines and BBQ tanks. It was the first thing I started work on after I quit my Wall Street IT job and moved from Brooklyn, New York to Truth or Consequences, New Mexico. I spent a significant amount of time going to Propane shops and completely lying about what I was building in order to purchase all the necessary valves and hoses. At one point I dismantled my electric scooter for the lead acid batteries. The source code is just about 700 lines. I was heavily dependent on the AVR JTAG ICE clone throughout development. The project ended up costing over $1200. Most of the expense was due to propane related items (hoses, valves, tanks, and regulators). A local art gallery in Truth or Consequences, NM called "Rio Bravo Fine Art" was generous enough to provide space for testing. Maker Faire in San Mateo California will be the first public appearance. This device has been tested in winds up to 25mph. Only open source software was used to develop this project. All firmware and circuit related files are free for download.

Files:

  1. Fire Permit (html)
  2. schematic (pdf)
  3. src (html)
  4. src (bz2 tarball)
  5. gerbers (zip)
  6. schematic (gschem format)
  7. pcb (pcb format)

Significant Parts:

Part Vendor qty price SMT
AVR ATmega64 digikey
ATMEGA64-16AC-ND
1 $11.83 64-TQFP
Solenoid Valve McMaster
4711K62
1 $83.43 N/A
5VDC/1A SPST Reed Relay Radio Shack
275-232
1 $2.79 No
Ultrasonic Range Finder - Maxbotix EZ1 Spark Fun
Sense-EZ1
1 $24.95 No
RFID Reader Module Parallax
28140
1 $39.95 No
NPN Transistor 2N3904 digikey
2N3904D26ZCT-ND
1 $0.19 TO-92
Headers (jtag) digikey
929836-02-36-ND
10 (5x2) $2.94 No
Power switch digikey
EG1847-ND
3 $1.11 No
Green LEDs 0805 LSDiodes
S-G084533
8 $0.45 0805

Press:

Issues:

  • The schematic and pcb are off. I changed out the ULN high voltage transistor part for a 5V reed relay that can handle 24VDC or 120VAC. This is used to trigger the solenoid.

Credits