Make 2008

OVERVIEW:

This page hosts specifications, documentation, concept art and images for three Maker’s Faire 2008 submission projects: an LED-array based grow light system for small plants, an audio component micro-system housed in stacked Altoids tins, and digital VU-meter using Macetech RGB Blocks that integrates with the audio micro-system.

Grow LEDs

• 5W dual LED array based grow lights for small plants
• Expected prototype cost: $50
• Device is competitive in application and wattage with:
  • $169 http://www.ledtronics.com/ds/plantled/
  • $170 http://www.led-grow-master.com/
• Uses 96 low-power, high-output, wide-angle red and blue LEDs
• Distributed heat sources for “On-Plant Lighting” distances
• 4 switched higher output white LEDs to provide full spectrum aesthetic lighting
• High-efficiency boost-mode SMPS supply
• BJT current source (as opposed to resistive) LED power regulation for immunity to poorly matched LED Vf
• Sealed, water resistant LED array modules
• CNC machined 1″ thick acrylic front chassis for LED arrays
• .250″ aluminum heatsink rear panel for opposite-plant heat dissipation and mounting hardware
• CAT5 Ethernet cable power transmission and interconnect
• Small plants to try:
  • Fresh Spices and Herbs
  • Bonzai Trees
  • Cactus and Succulents

Curiously Strong Component Audio

• Altoids Mints tin based audio component system
• SOIC and 0805 SMT package based. Suitable for intermediate soldering skill kits
• Planned Curiously Strong Components (listed in order of fabrication priority):
  • Power Amplifier (Chipamp based. 5-10W RMS at <1% THD into 4 or 8 ohms)
  • 2-WayActive Crossover (Linkwitz-Riley aligned 24dB/octave active filters)
  • Preamp (Volume, balance, gain, bass and treble controls)
  • Source Select (Input signal selection switches)
  • Equalizer (4 or 5 band. Based on bessel and constant-q active filters)
  • Headphone Amp (Chipamp based. 200mW RMS at <0.5% THD into 16 or 32 ohms)
  • 3-Way Active Crossover (Tri-amps are erotic)
• Automatically stacking with neodymium magnets
• Based on common BOSS effects pedal power supplies (PSU fanout cable is available)
• 1/8″ (3.5mm) stereo miniplug interconnects
• Minimalist design philosophy (the only set of Audiophile principles that make sense)
• Speaker cabinet technology currently unknown. Possibilities:
  • Coffee Cans (sealed or open baffle)
  • Altoid Sours Tins (open baffle)
  • CDR stack container (sealed)
  • Custom Fabricated Acrylic (sealed or open baffle)

• Electronics Parts List:
  • 0805 Stacked Ceramic Chip Capacitors
  • 0805 Metal Film Chip Resistors
  • TL072 Dual Opamp SOIC8
  • 12mm Stereo Audio Potentiometers
  • 3mm Power Indicator LEDs
• Mechanical Parts List:
  • Altoid Mints Tins
  • Neodymium Button Magnets
  • Clear Rubber Adhesive Backed Feet

Darker Macetech RGB Block VU Meter

• Based on Macetech RGB LED Blocks
• Made to interface directly with Curiously Strong Audio units
• Sense and control interface built into an Altoids Mints tin
• VU meter display in average or realtime modes
• User selectable color themes

PROGRESS:

• General feature set and system architecture brainstorming
• Initial block diagrams
• Initial part selection and aquisition
• Confirmed crossover project with Macetech

GALLERY:

Block diagram and concept art for the Grow LEDs project.

Block diagrams and concept art for the Curiously Strong project.

Some previous Chipamp based projects, including a headphone amp based on the Natsemi LM4881 audio IC built into an Altoids tin. Also included are various Gainclone/LM3875/LM3886/LM4780 based chipmp boards. The LM4780 was a bridged design based on National’s BPA-200 application note.

Projects and designs with active filter, crossover, and preamp circuits. The DIP populated board is a Linkwitz-Riley aligned 2-way active crossover with 1% polypropylene caps and TL072 opamps. The SOIC layout and milled circuit board (MCB) are part of a audio input/output project for the Olimex SAM7-H256 dev kit, and include both a preamp-style input circuit and a four-pole active filter.

Posted by rmrubin March 2008