Introduction: AMOEBA LEVEL: a CUSTOMIZABLE SPIRIT LEVEL

By Namit Agrawal
About: I am a Mechanical Engineer by profession. I also have a M. Tech. degree in Mechanical Engineering.
A spirit level is an easily available regular measuring instrument. Most of them are not that expensive. Ability to make one with simple tools economically and without loss of accuracy is what makes the difference. This allows a spirit level to be installed in almost every other project. Even use-and-throw type spirit levels are possible.

Salient Features
  1. Simple to make yet can beat many of its counterparts
  2. Combines at least three spirit levels i.e. horizontal, vertical and 45°, in one
  3. 360° level i.e. works in all directions
  4. Accurate and precise
  5. Inclinometer
  6. Economic
  7. Highly custimizable
    • Sensitivity of spirit level
    • Properties of spirit level liquid like colour, surface tension and viscosity are customizable
    • Shape of outer body
    • Bubble size
  8. Mountable
A personalized logo can also be marked on the level.

This spirit level was not originally inspired from amoeba. Rather name was kept because it suits the spirit level. Amoeba can assume any shape. It is a cell consisting of different parts with cell membrane, cytoplasm and vacuole being the relevant ones. These features of amoeba can be found in this spirit level as follows:
  • Cell membrane corresponds to the body of spirit level
  • Cytoplasm corresponds to the spirit or the liquid used in spirit level
  • Vacuole corresponds to the bubble of the spirit level
  • The capability of amoeba assuming any shape corresponds to the level of customization this spirit level can achieve
There are some things that are to be taken care of while making a spirit level. For instance,
  1. What is the principle of working of a spirit level?
  2. How to calibrate or check a spirit level?
  3. What are the desirable properties of the liquid filled in the spirit level? For instance,
    • It should not wet the surface of the tube
    • It should be easily visible
  4. What should be the size of air bubble?
These questions and some other aspects form the content of further steps. Accuracy, precision, level of functionality and built quality are considered as the parameters that define quality of the spirit level. Some of the desirable features of spirit level are taken just by observing commercial spirit levels.

One more point. This spirit level has the spirit of spirit level and not the spirit as liquid! That's why this can be called as spirit level even when there is no spirit in it.

Step 1: MATERIALS REQUIRED

The following materials and tools will be required for this instructable:
  1. Saw
  2. Cutter
  3. Syringe
  4. Glue stick
  5. Drill press
  6. Wax polish
  7. Common salt
  8. Black gel pen
  9. Instant adhesive
  10. Sand paper (#540)
  11. Glycerine (optional)
  12. 3mm transparent acrylic sheet
  13. Water (preferably distilled water)
  14. 3 geometrical shapes, triangle, circle and octagon
  15. Tri-square (this is required for all right angles and straight edges)
  16. 32mm hole cutting saw (other diameters as per requirements can be used)
  17. Highlighter (green colour recommended; yellow for exact colour; sketch pen may also be used but it will not glow in UV)

Step 2: DECIDING RADIUS OF CIRCULAR CAVITY

Larger (http://www.leveldevelopments.com/sensitivity-explained.htm) radius means more sensitivity. This site was used for finding out the sensitivity for amoeba level. The site can be used for determining radius for given sensitivity. This also limits the maximum radius of curvature for this spirit level.

For this particular spirit level the sensitivity is 6° for 38mm radius (see photograph). This much sensitivity should be sufficient for most projects.

Step 3: THE CELL BODY

Triangles
Present amoeba level is designed in shape of 30°-60°-90° set square. This has a purpose. This design allows inclining of objects at three different angles. Needless to say, any combination of angles may be used for the triangular body as per requirements. Even the triangular shape can be dropped. Any regular or non-regular geometrical shape is possible.

One advantage with this design is that using the other 45° set square several other angles are possible without the need of building other spirit levels. Later it will be shown that by using octagon as marking even 45° angle can be measured.

Three triangles of same shape were cut from 3mm acrylic sheet. At this time is important to make all the angles as accurately as possible. Also the flatness of the sides should be ensured.


Circular cavity
In one of the triangle a circular cavity was cut using 38mm hole cutting saw. The centre for this circle is the point of intersection of angular bisectors of all three angles. This cavity is to be used for filling the spirit level liquid.


Final Assembly

NOTE: Using wax polish, the triangles other than the one with hole are polished before final assembly. Wax polish increases surface tension and helps in reducing wetting of surface.

Now all three triangles are stuck together with instant adhesive. Care was taken to make the cavity air tight. Before pasting the third triangle, a 1mm hole was drilled at non-interfering position for later filling of spirit level liquid using syringe. After pasting all three triangles, a circular piece of paper is cut and pasted using glue stick on both sides of completed body. Next the surfaces are sanded for rough finish. Also the edges of body are sanded finally for correct angles.

Step 4: CYTOPLASM - THE AMOEBA LEVEL LIQUID

Surface Tension and Problem of Wetting
Broadly speaking increasing surface tension will reduce the wetting. This is achieved by adding common salt to distilled water as additive.

Wax polish done in earlier step also increases surface tension.This step is should not be missed.


Viscosity, Damping and Bubble Travel Time
Next viscosity of water can be increased by adding glycerine. Simple way to know what amount of viscosity is preferred by you is to note that how much time you want your bubble to travel and also how quick damping you want for the bubble. Both requirements cannot be varied simultaneously. Higher viscosity will lead to quick damping but increased bubble travel time and vice versa.


Colour
Highlighter was used for providing the flourescent colour to liquid. Highlighter was dipped in distilled. Since, depth of cavity is just 3mm, darker colour is recommended. So dip highlighter more and more. I have tested this solution in uv rays. The liquid so obtained glows in uv rays.

The photograph compares four different colours, pink, blue, green and yellow. I recommed green but you can go for yellow if you want exact colour of commercial spirit levels.

Step 5: CALLIBRATION USING OCTAGON

Octagonal shape was selected for calibration of amoeba level because it is simple and allows measurement of 45° angles without need of additional set square.

The following steps were taken for calibrating the amoeba level.
  1. First the amoeba level is filled with liquid using 1mm hole and syringe. The hole is later sealed with small piece of cello tape. Use of cello tape allows future adjustments in amoeba level liquid.
  2. An octagon was drawn on 38mm circle. This circle was pasted on the circular cavity such that one edge of octagon is parallel to one of the sides other than hypotenuse. Size of octagon depends on the size of bubble. First the bubble size is to be decided by hit and trial then the octagon size. Present bubble height is 4mm when amoeba level is in upright position. Hence, the edge of octagon is 4mm away from the circular edge.
  3. Now using cutter, the markings are scored on the acrylic using paper as template.
  4. Next the paper template is removed.
  5. Next, black gel pen is used for blackening of scored markings.

Step 6: FINAL CHECKING AND COMMENTS

Checking
The following method from wikipedia was used for final check amoeba level for accuracy.

From Wikipedia:

To check the accuracy of a simple carpenter's type level (i.e. whether the level indicates that a truly horizontal surface is, in fact, level), it is placed on a flat and approximately level surface, and the reading on the bubble tube is noted. This reading indicates to what extent the surface is parallel to the horizontal plane, according to the level, which at this stage is of unknown accuracy. The spirit level is then rotated through 180 degrees in the horizontal plane, and another reading is noted. If the level is accurate, it will indicate the same magnitude of orientation with respect to the horizontal plane. A difference implies that the level is inaccurate and must be adjusted.

Adjustment of the spirit level is performed by successively rotating the level and moving the bubble tube within its housing to take up roughly half of the discrepancy, until the magnitude of the reading remains constant when the level is flipped. Note that a perfectly horizontal surface is not required. (SOURCE: http://en.wikipedia.org/wiki/Spirit_level)


Comments

  • Through holescan be drilledaround the cavity for mounting amoeba level to another project.
  • Any marking other than octagon may be used.
  • Amoeba level can also be used as a tri-square.
  • Small bubble works well but should not be smaller. Its size should be decided by trial and error such that bubble retains its shape when amoeba level is turned around.
  • Amoeba level combines at least three spirit levels in one. That is, horizontal, vertical and 45° levels (see photograph). Its also a 360° level.
  • Single amoeba level can accurately measure 30°, 45°, 60° and 90° angles.