Weight has beaten me at the moment, the small cell i agreed to use is thick acrylic with a top that seals and micro port holes in the side, it would have been ideal for this, but its built for special high pressure reactions and considering its size its really heavy for what it is.
So i am negotiating to use something else a little bigger but alot lighter, its likely to be roughly the same volume of sediment, but the shap is a bit different and its harder to seal and attach a proton bridge too. I wont be using nafion for the proton film (way too expensive) but i am looking into using HCL treated Alginate for the bridge.
Often e.Coli in a broth is made into a agar bridge, but it takes ages and isnt going to be good enough for this, same with the terracotta type salt bridges, these tend to let oxygen into the Anode half of the cell. I got the alginate idea from doing microbe and yeast beads with it, if you treat them with a chloride then the outside forms a permeable skin. No ide if it will yet but i have one in the making.
Motors are down to a choice between one of two small 1V motors, no grunt at all in them, but with a toy plastic wind up helicopter gearbox, they should be able to make the car move, geriatric snail with a walking frame pace is fine
. The micro and radio set up is all ultra low power and the board to get a decent voltage is a choice between two linear tech energy harvesting boards. I have a number of 2F super caps that are pretty small, so i will add some to the cap bank.
I dont think its cheating to store the microbe cell energy for boosting the transceiver etc when needed, seeing as all the power is from the cell itself. I gave all my balsa wood away the other week, so i am using a light stiff (ish) foam for the frame of the car. When i can be bothered i will go through the torture of taking pics and uploading them once i have messed around and screen shot so they fit the dismal upload limit.
Or i might stick the pics on my server and just link to them here. The sediment container was dropping the oxygen off nicely, then i got a small spike in Oxygen!! Small panic until i found out that apparently these types of sediments often have a spike in O2 just before the microbes we want start to take over, so with luck the cell might be ready to transfer the sediment soon.
The transfer is the worse part for me, i am going to use a glove box and because i am tight i will flush out with Butane and use that as my oxygen free atmosphere. Butane shouldnt harm the microbes (famous last words).