20140421 (M) ESPeri.Impass

When I write these journals in my notebook I try to keep myself out of it.  I try to write as though these are merely events that happened and my involvement is inconsequential.  This is about the writing after the break (----------) not what comes before it which is chock full of me and my opinions.  I also try to use formal language and word choice.

In other news not related to this project; I found a power supply for the 3D printer while rummaging through the goodies box at the hack space.  2.4Amps at 5VDC.  That will be more than enough power for those servos and any sensors I attach in the future.

Enough background.
After reading discussions on biohack.me an idea formed for a compass suspended by liquid.  The original idea was to have a sphere inside a sphere where the inner sphere is a compass.  It would have protrusions which would interact with a whisker.  The whisker would be protected against accidental triggering by protrusions on the inside of the outer sphere.  Natural movement by the subject would activate the whisker during movement. *see Journal Page 1*

The second iteration of the design was vertical and tubular.  This design makes use of conical floats (corks) and cylindrical containers (jars).  These were purchased from Michael’s.

The first float was drilled using a 9/16” Forstner drill bit.  It was a blind hole with the intention of mounting a disc magnet vertically in the recess.  The cone was propped with a wood chip so the hole would be perpendicular to the axial line of the float.  The disc magnet was held in place with hot glue.

Drilling a float

A mounted magnet

The buoyant force was too great so the float was clamped and cut on a band saw.  Once a large portion was removed the float was sanded which proved slow so another smaller portion was removed using the band saw again.  The buoyancy was coming under control but the device did not float level.  The magnet was removed and the hole through the float was continued.  The magnet was glued back in place with hot glue.  At this point the float was balanced and just barely positively buoyant.
Clamped magnet

 Reduced float
Sanded float

Float on emery cloth

Magnet mounted in float

Floating at the surface

The compass cone was suspended in a cylindrical container with tap water.  Its properties as a compass were tested by rotating the container and observing the orientation was not adversely affected.
Compass in front of container 
Spinning on a chair with a compass
A hair-like protrusion was made from a magnet face with the glue gun.

Hair-like protrusion on a magnet face

A second version of the spinner was made by drilling a blind 7/16” hole in to the smaller face of a float.  It was made deep enough to contain a spherical magnet.

 7/16" Forstner drill bit

 Day's result

To do:
  • Finish spherical magnet spinner.  Reduce -> Glue -> Add protrusion
  • Modify container to have a protected whisker
  • Finish dry wooden biscuit versions
  • Test and evaluate
Journal Page 1
Journal Page 2