B E A M - R o b o t i c s
Biology - Electronics - Aesthetics - Mechanics

BathesVore mk I


Project status : Finished
Last update : 9 May 1998



Parts used:


Solar engine

  1. SE designed by Steven Bolt and Ken Huntington
  2. Click here for a full description
  3. Solarcel type :


Motor

  1. Pager motor
  2. Sunlight or artificial light


Other items

  1. Wood
  2. Screws
  3. TL tube as dive tank
  4. Pritt stick for casing
  5. Silicon kit
  6. Brass caps
  7. Water
  8. Inkt [ecoline]
  9. Pencil filling for an axe
  10. Small propeller
  11. Oil


Tools

  1. Solder iron 18W.
  2. Clothes-peg
  3. Knife
  4. Plier
  5. Cutter
  6. Scissor
  7. Screwdriver
  8. Grindstone
  9. Digital multimeter
  10. Towels



M
y goal was to build a object that could dive and surface again. This last piece would be the most interesting part of it. I had five problems to overcome. First i needed a name for it. I choose 'Bathesvore' because it sounds good and it will give a phonetic link to a bathysphere. A bathysphere is an object that can dive to the deeper parts of the ocean.

I wanted to show this bathesvore in my livingroom. This means poor light conditions and subsequently also the need for a solar engine that can operate at dim light conditions. The solar engine found on the pages of Steven Bolt could do the job.

The 3rd problem was the diving tank. Since it will be placed in my living room it had to be something nice to look at. Not some bulky thing like a aquarium but something more stylish. I know for sure that i've found a very suitable diving tank and that it can be nice to look at.

The dive tube
A few year ago i had made one all ready and ever since it was hanging in my livingroom. In all those years i only received good compliments about it. And they always asked me "what is it?". I made it from a large TL-tube. With a grindstone i removed the endcaps. I didn't managed to make a nice clean cut but that doesn't matter. The new endcaps will hide that later on. The inside of the tube is filled with a powder [toxic, be careful]. This powder i removed with water and a piece of clothing. Just pressed the clothing through the tube and washed the powder out. Now i had a glass tube with an inside diameter of 35 mm. To close it again i made two caps of brass and glued one of them with silicon kit to one side of the tube. You can also use a cap from a spray can or such. Just go shopping with a ruler and find your cap in the supermarket. From wood i made a frame to hold the tube in a upright position. I filled the tube with a few drops of coloured ink and water. This ink is just added for the coloured effect. The top cap was placed and i hung the complete frame on the wall. My diving tube is finished.






The next problem i had to overcome was friction and erosion. I didn't want to get my motor and electronics wet. To prevent this i placed the solar engine and pager motor in a top sealed casing. This casing was a Pritt stick from Henkel. This is a glue stick. I just emptied the stick. I removed the glue and push mechanism. Btw, any other casing that would fit in the TL-tube will be fine. A good option is also the plastic container inside a suprise chocolate egg. And the push mechanism can be used as a linear actuator.
The casing still has one hole at the under side. The side where the propeller has to come. If the casing is forced to stay in this upright position then water can't come in the casing because there is air locked inside. This allows the axle to turn without friction cause by a seal. But water will vaporise at a small rate. This will raise the humidity of the concealed air in the casing. This humidity will eventually cause erosion of the components. To prevent this i place a few drops of machine oil inside the casing. When the bathesvore is place in the tube the oil will form a thin layer at the surface of the water inside the casing. This layer will prevent that the humidity will raise inside the casing.

The last problem i had was position the solar cell towards the light. If i use a flexible solar cell then i could wrap a tube of it and glue it to the out side of the casing. This way the solar engine will always being charged. The downside of this is that you use your solar cell very inefficient. But since i don't have these cells i decided to use a lesser elegant solution. I added a 'wire-eye' to the casing and placed a long messing rod of 2 mm thick in the tube. The ring would glide up and down along the rod and keeps the solar cell always directed to the light.

Assembling the bathesvore is easy. The PCB of the solar engine is fixated in the casing with glue and foam. The pager motor is clicked into a fuse holder and facing downwards to the small hole in the underside of the casing. The wires from the solar cell are let through a small hole in the side of the casing. The little hole is closed again with glue to make it waterproof. A ballpen filling is prepared to be used as an axle and let through the small hole at the under side of the casing. One side of the ballpen filling is pressed on the pager motor axle and at the other side a small propeller is fitted. The solar cell is glued to the outside of the casing. The complete assembly is placed in water and balanced out with extra weight. The bathesvore must just keep floating. So it will go down easily and will go to the surface again when the propulsion stops. Place the bathesvore now in the dive tube and attach it to the guiding rod. Put the top cap on the tube and let light do its work.


Tip
A very neat idea came from a builder called Kyle
He suggested the glue the solarcell on top of the diver and to place a lamp in the top cap. This will light the tube nicely and will power the solarengine in a simple manner.


I hope this page will expand your imagination.

Bram



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A.A. van Zoelen's site / vsim@mail.com
Updated: 26 Oct. 1999