MATERIALS AND TOOLS
Mud Watt MFC Kit item #MKKT01 from Maker Shed
( makershed.com), $45. Includes all materials below,
except mud. You can also build MFCs from scratch,
minus the Hacker Board.
» Container, waterproof, with tight lid
» Graphite fiber cloth ( 2 pieces) sized to fit in container.
The kit has 2 rounds, ¼" thick and 33" diameter.
» Marine wire, 16–20 gauge, 4" longer than container height ( 2) Using 2 different colors helps.
» Grommets, rubber ( 2) sized to seal marine wire
through holes drilled in container lid
» Mud Watt Hacker Board includes voltage-boosting
chip, 8-pin socket, 22μF capacitor, resistors, and red
LED that blinks when bacteria generate power
» Gloves for mixing the mud
Mud Almost any mud with organic compounds will
work. Try freshwater ponds or streams, brackish
swamps and inlets, or saltwater marshes. Try to find
mud that bubbles when disturbed or smells like rotten
eggs — both are good indicators of anaerobic bacteria
(but don’t worry, your MFC won’t smell). You can also
use soil (just dig down a foot) or compost from the
warm middle of a heap.
Drill and drill bit (optional) if drilling your own lids
Multimeter (optional) for testing power
flow through wires to a cathode sitting in
water above the mud, where they combine
with oxygen to complete the circuit. The bacteria are highly efficient in this arrangement
and can produce electricity continuously for
many months or even years.
They also support online discussion forums
for MFC makers.
With the Mud Watt, students of all ages are
learning about MFCs and making scientifically
relevant discoveries. For example, a 6th-grade
student in Santa Cruz uncovered (literally) a
river sediment that produces twice as much
power as typical topsoil.
Make Your Own MFC
1. Mix your mud (or soil or compost) to saturation with water and put a ½" layer into the
bottom of your container. You can experiment
by adding extra ingredients; see keegotech.
com/community/education for ideas.
2. Cut the 2 pieces of graphite fiber cloth to fit
the container. Be careful not to disperse the
fibers in the air because they can cause short
circuits in household electrical equipment.
Strip 4" from one end of each piece of
marine wire, and weave each through a piece
of graphite cloth. Strip the other ends ½" and
thread each through a grommet. Drill the lid
of the container to fit the grommets.
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