Exco and makefu finished the prototype of the first rgb cube.
T61 fan repair session with 3,3V mini-pci express
Introducing the shacklogger
makefu wants to establish a new process to show off what is happening in the shackspace more easily.
By utilizing log.shackspace.de tumblr account, a spare Nexus4 phone and a QI charger everyone in the shackspace will be able to make a quick snapshot of his finished/WIP project without much hassle and show it to the world.
Just take the phone, make a photo and post it!
Reclaiming Copper from Sodium Persulfate #4: 6B Pencil Lead Anode
As previously noted I’ve decided to give softer sketch pencil leads a try.
It looks like the electrodes are more efficient and a bit more stable. I’ve also noticed that the solution seemed to have taken on a lighter blue color and the copper cathode seems to have gotten thicker. In principle it seems to work!
However, the thicker anode too started to disintegrate after a few hours at 2 to 2.1 V.
It’s time to go back to the drawing board and see if it would make sense to get either a properly manufactured graphite or coal electrode or even go all out and get a platinum one.
Reclaiming Copper from Sodium Persulfate #3: Bigger Graphite Anode
I tried scaling up the graphite anode by connecting several sketch pencil leads together.
I’ve done this using single strands of stranded copper wire to weave and knot the individual pencil leads together. Once tightly woven into place I’ve finalized everything by adding generous amounts of solder.
With regards to being able to use higher voltages this was no help (of course) and the pencil leads still disintegrated.
What I’ve learned:
- Fellow hacker reloc pointed out that the softer a pencil lead, the more graphite it contains. I’ve picked 2H leads for my tests so far and will switch to 6B leads (the softest I could find at short notice).
- What is going into solution depends on the voltage applied (potential) and which materials of lower potential are still there (if available, the lowest energy bond breaks first, even with high voltages).
- Documented potentials (see: Pauling electronegativity) are usually defined for platinum electrodes. If you’re using something else, you have to apply a correction value. Also thanks to reloc for helping out with all the theoretical science behind the experiment!
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