HomeRoast Digest


Topic: OFFLIST: Re: +Adjustable popcorn popper (141 lines)
1) From: David B. Westebbe
This is a multi-part message in MIME format.
Scott - 
 
I have nothing so sophisticated as a parts list.  I've been using my =
'Pumper
as a modding platform for a bunch of years, and have added to it as time =
has
gone on.
 
I've been thinking of taking some pictures of the inside, and sending =
them
to Ed for the homeroasters.org site.  Your request may be the impetus I =
need
to finally do it.  I'll let you know.
 
Here's a short version:
 
First, I widened the slots for more airflow and larger batches (I can =
roast
just under a half-pound now).  But then I found that there was too much
airflow - the air didn't get hot enough to reach cracking stage.
 
So I did the transformer/dimmer mod to turn down the fan. I got a =
plastic
hobby box to mount stuff in, and integrated it all into the case. The =
dimmer
needed a bunch of stuff trimmed away to fit, and it was difficult =
finding a
suitable transformer that was small enough to fit.  I have a second
transformer that I might install in parallel with the first to supply =
more
juice.
 
 I use switches to turn on the main power and the power to the heating
coils.  I set it up so that the coils could not get juice unless the fan =
is
also turned on - it seemed safer that way.
 
I installed a 12 gauge power cord so that there would be no bottleneck
there.  I also drilled a bunch of holes in the beancup to better =
distribute
the heat, and I drilled a bunch of holes in the plastic case so that =
enough
air could pass.  I use a hurricane lamp chimney on top, to keep the =
beans
from flying out.
 
I played around with temp sensors - thermocouple(s) and Polder =
electronic
thermometers, with holes drilled in various spots for the probes.  That =
kept
me entertained for years.  I use a K-type thermocouple in the heat =
chamber,
near the coils, so that I can monitor the air temp.  It got to be a PITA =
to
have a wire hanging out for the external readout, so I decided to mount =
a
simple digital temp readout on the popper itself.
 
I found it impossible to find a suitable temp readout!  I cannibalized =
my
el-cheapo electronic thermometer, and tried to build it in.  But due to
unusual connectors, I was unable to do it.  
 
Finally, I searched eBay for a suitable digital readout, and stumbled =
upon a
1/16 DIN PID controller.  It sort of fits, with lots of internal mods to =
the
popper.  I was going to just use the digital readout portion, but then
realized having a PID control might be a lot of fun.
 
So I bought a suitable Solid State Relay (again - it was hard to find a
small one) and tried to fit the rats nest of wiring inside the case.  In
order to do so, I had to disassemble everything and use junction blocks =
for
the wiring connectors.  That kept things neat enough so that it all fit. =
 
 
So now my toy is very versatile.  Big loads, small loads, fast or slow.


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