Stir Plate Electronics

Comment by Glynn Foster on July 13, 2009 at 3:32pm

Yay, it spins! Just need to pick up some magnets and a stir bar. Hooked this up to a 12V adapter after sifting through a box full of old mobile phone chargers (unfortunately they're all a bit soft at 3V-5V). Still though, 25 Ohm rheostat not quite doing the job I expected in being able to slow the fan down proportionally across its resistance. Badly need to do an electronics 101 - my weenie software background isn't helpful here.

Comment by denimglen on July 13, 2009 at 4:24pm

You need this little LM317 kit that DSE used to have but don't seem to stock anymore, works a treat in mine, just swap out the fixed resistor to a variable type.

Comment by James P on July 13, 2009 at 4:30pm

We were lucky enough to pick up a potentiometer from tardme which provided a ridiculous level of adjustment for our stirplates. (Weenie software background phffft....not from what I have read)

Comment by Glynn Foster on July 13, 2009 at 4:38pm

Denim Yeah, a lot of the stirplate tuts seem to talk about LM317. Tempted to start playing with the Arduino and start bridging the gaps between beer and geek.

Comment by denimglen on July 13, 2009 at 4:53pm

Not a bad gap to bridge, fully automated HERMS/RIMS, software controlled?

Dunno how much a software controlled stirplate would do, but shit, would be fun.

Comment by Glynn Foster on July 13, 2009 at 4:56pm

Start easy, then start to get more complicated as bits are added to the system. But you're right, there's only so much you can do with a stirplate :) (was thinking HERMS/RIMS too)

Comment by Ged on July 13, 2009 at 8:00pm

This is the same one - http://www.trademe.co.nz/Electronics-photography/Other-electronics/...

he is listed under EPA as the seller...The only downside I would say is the adjustment is probably too fine i,e 10 full turns end to end...However it does allow for tiny adjustments in speed.

Comment by Glynn Foster on July 13, 2009 at 8:26pm

Gives me a good idea of what Ohmage I should be looking for, thanks Ged.

Comment by Glynn Foster on July 13, 2009 at 10:17pm

Curious about where to go for lab stuff - has labwarehouse.co.nz worked out ok? Also thought about globalscience.co.nz, which seems to have local office in Wellington. Thinking about getting a couple of stir bars, and a few capped test tubes.

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