Wow, Alek, I did not know this video, amazing! I have some friends who
speak Polish, I guess they can help me. Are there more of these videos?
I have now found a reasonably priced vacuum sensor at mouser.com, it is
called SSCDANN015PA2A3, that means: Absolute pressure sensor, 0 to 15
psi == 1 bar, 14 bit resolution, I2C interface. It costs about 25EUR,
that is quite affordable, I can build the rest of the electronics at
home, no problem with that. In fact, I have never used I2C before, but
that won't hold me back ;-).
At the university I have made some tests with an ancient rotary pump and
it went down to 2mbar which is OK I guess. I will purchase one of these
cheap pumps used in refrigeration and test it with the university's
vacuum meter, and if it is fine, I will keep it, and if not, I will
return it.
Best regards,
Jens
Am 15.01.2012 16:05, schrieb Aleksander Zawada onet:
When I started, I used car light bulb as Pirani's gauge. I used my
own glass oil diffusion pump (only 1-stage) and rotary pump. If you
want, you can see here:
http://www.youtube.com/watch?v=TJ0Pm4swoOo
Unfortunatelly, only polish language.
W dniu 2012-01-15 00:42, David Forbes pisze:
On 1/14/12 6:30 AM, jb-electronics wrote:
Hi,
Vacuum gauges are made by Varian. There's a panel meter and a little
metal gizmo with an octal base like an old vacuum tube. Look on ebay.
thanks, I did. The actual gauges are quite pricy, maybe I can use a
more
ordinary pressure sensor and build a gauge of my own.
Thanks again,
Jens
An ordinary pressure sensor is useless for below 10 mbar, since the
resolution is poor. The fancy ones use an ionization sensor to get an
accurate reading at very low pressure.
And I made a mistake - it's not Varian you want, but Hastings.
Google for 'hastings vacuum' and you'll find lots of meters and
sensors. The meters are $150-250 and the sensors are $50-100. But
they work well.
The other brand of vacuum gauge that we use is Pfeiffer/Balzers, but
they are really expensive. They go down to the microtorr level, though.
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