Support TEH House! Your donation helps keep this information, representing hundreds of man-hours of
work, online and advertisement-free!


Mother Bug
- A sweet, motion-activated LED sign -



Completed Mother Bug icon

     Mother Bug is an interactive electronic gadget I designed and built for my mom as a Mother's Day gift. It is built almost entirely out of spare parts and scrap materials; making it both a unique and eco-friendly device. Who says making gifts can't be a fun and educational process?


The Idea  |  Materials  |  Schematics  |  Casing  |  All Photos



The Idea:

     Mother Bug is a simple, interactive electronic message board... disguised as a "bug." Text messages are pre-programmed into the memory of the device's microcontroller. When triggered, the microcontroller uses a 5 x 7 LED matrix display to print out the messages. Some messages / icons are static and others scroll across the screen when displayed.

     Mother Bug is always on, but it normally "sleeps" in a low-power state when not active. It is activated when motion is detected in close proximity to its "eyes". The "eyes" consist of two infrared (IR) LEDs, one used as a transmitter, and one used as a receiver (respectively). The presents of a hand or other object near the LEDs causes the IR light from the transmitter LED to be reflected back into the receiver LED. After the device wakes up, it prints one of the pre-programmed messages; chosen at random. Mother bug then returns to its low-power "idle" state.

     Although I purposely designed Mother Bug to be an over-the-top Mother's Day gift, the microcontroller firmware could easily be changed to turn it into a more useful device. If I build another version of the device I'd definitely install a serial port on it. This would allow it to do very easily be a remote display that could show weather info, time, RSS feeds, etc...


Materials List (Electronics):

  • (3) [ C1-3 ] 0.1uF, 16V, ceramic or film capacitor
  • (1) [ C4 ] 0.33uF, 50V, ceramic or film capacitor
  • (1) [ C5 ] 560uF, 16V, electrolytic capacitor
  • (1) [ IC1 ] Atmel ATmega88 Microcontroller
  • (1) [ IC2 ] LM7805 voltage regulator
  • (1) [ JP1 ] 2x3 male pin header, 2.54mm pitch
  • (1) [ LED1 ] 5x7 LED matrix, red, rows=anodes
  • (2) [ LED2,3 ] 5mm, infrared LED
  • (1) [ L1 ] 10uH inductor
  • (8) [ R1-8 ] 150-ohm, 0.25-watt resistor
  • (1) [ R9 ] 1-Megohm, 0.25-watt resistor
  • (1) [ PS1 ] Power Supply / Wall-wart, 10-18 VDC, 100+mA

Schematics:

     The schematic for Mother Bug, version 1.1 is shown below.

Mother Bug Schematic
Mother Bug Schematic - Version 1.1


Casing:

     When I first came up with the idea to make the electronic circuit part of Mother Bug, I had no idea how I would package the device. I was originally considering mounting the LED display and circuit board behind a small piece of clear plastic such as lucite or lexan. However, I decided it would be cooler to try and make the casing for Mother Bug more of an art piece.

     I ended up designing the casing for Mother Bug around a 2 inch diameter PVC coupler because I had extras laying around. The coupler I used is gray because it is designated for use with electrical PVC conduit. I used a drill to create two holes for the infrared LEDs, and a Dremel to route out a rectangular opening for the LED matrix display to show through.

Mother Bug Casing      Mother Bug Casing      Mother Bug Casing
Transforming a PVC coupler into a case for Mother Bug.

     In order to keep dust and bugs out of the electronics, I hot-glued two end caps into the sides of the PVC coupler body. I cut the side pieces out of some scrap lexan with a hole saw. Because the body of the Mother Bug is curved, and the center of gravity is high up in the casing, it has a tendancy to roll around. To prevent this, I glued two old electrolytic capacitors to the casing to serve as feet. Lastly, to finish off the "bug" appearance, I glued two small springs to the top so that Mother Bug would have antennae (all awesome bugs have antennae!)

Mother Bug Casing      Mother Bug Casing      Mother Bug Casing
End caps, capacitor-feet, and spring-antennae finish off the appearance.



Mother Bug Photos

Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL
Photo Gallery Mother Bug
Large
|| XL