hey everyone I thought I'd
give you an
update on my cookie machine
project so I
don't know if you saw the
first video
but I basically got this
carousel sort
of device that I've rigged
up and each
station on the carousel is
going to have
one of the ingredient
components to make
a chocolate-chip cookie and
the
challenge one of the
biggest challenges
with this project is
handling all the
different types of
ingredients every
station looks pretty
different because
all the ingredients have
different
properties to them that
require a
different dispensing method
so I figure
I'll go through them
briefly and then
describe what I got done
over the last
few days this will be the
station that
dispenses chocolate chips
so the chips
will be stacked in here and
as you
rotate this a specified
quantity of
chocolate chips will be
dispensed out
the bottom the trick is
that this volume
is a little bit too big
right now so
what I'm going to do is
just add some
solid plastic between the
fins on that
sort of butterfly valve
that way when
this thing comes around
it'll pick up a
smaller subset of chips but
still
dispense a specified number
each time
this will be the dispenser
for brown
sugar brown sugar is
probably one of the
most difficult to dispense
ingredients
materials that I've ever
seen it's
sticky it's granular it's
also not very
free-flowing like it's it's
it becomes
solid like if you leave it
in a cup you
can actually turn the cup
upside down
and it's all packed
together so all
these properties make brown
sugar very
difficult to deal with so
I'm going to
use the same trick that I
used with the
chocolate chips I'm going
to sort of
pack that butterfly-valve
up with more
plastic and the trick is as
it rotates
around it actually has sort
of like a
grinding action so if the
all the brown
sugar up here is packed as
this thing
turns around the fins kind
of chip off a
little bit of it so as this
you know it
may not get exactly the
right amount but
we're going to be using the
valance to
actually measure the amount
of
ingredients that have come
out so what I
can do is just make the
volume in
between fins smaller and
smaller and
just use more rotations to
get enough
total volume out some of
the easier to
deal with ingredients are
say the sugar
so this is granular
but it's pretty
free-flowing and so the
method I'm going to use for
both sugar
and salt is a helical screw
on hand
drill bit in this case this
is a high
helix angle drill bit and
is it there's
a chamber in in here that
looks about
like this so when the drill
bit turns
counterclockwise it pulls a
little bit
of the salt in this case
out and there's
a dispensing port on the
bottom I'm
using tape just to hold
this together
for now what I need is a
little pulley
system which I've already
ordered the
parts for but the motor
speeds and the
volume within the drill
bits and
everything have already
been tested -
these work the flour I
initially had
some problems with - until
I found just
a small sifter that I could
put in my
carousel like this so it's
a really slow
motor the high gear ratio
it just turns
the sifter and it dispenses
a
surprisingly consistent
amount of flour
per revolution of the
sifter this will
be for the eggs someone
asked if I was
going to do egg yolks and
egg whites
separately no but that's a
good idea in
this case what I'm going to
do is just
beat the eggs together and
put the
blended eggs into this
syringe
dispensing the liquids is
super easy
compared to the powders and
the brown
sugar and all that stuff
this will be
for the vanilla extract
Sam deals the eggs pretty
much this will
be for the butter the
reason I'm using a
metal syringe for the
butter with this
other apparatus is that it
has to be
temperature controlled and
it also is
going to be experiencing
much higher
pressures in the syringe so
this metal
syringe was needed because
I didn't want
the glass to break so that
leaves two
unpopulated stations here
one of them is
going to be for baking soda
and the
other is going to be for a
mixer which I
may or may not implement in
this first
version so the idea is that
the carousel
would turn around dispense
an ingredient
on the scale you know turn
to the next
station dispense that
ingredient and
then turn to the mixer
station the mixer
station would actually go
down into the
into the cup and mix the
ingredients
together I think for this
first shot
what I'll do is just you
know have the
thing a little bit more
user involvement
so it'll dispense the
ingredients and
then say okay mix those together
and
then dispense three more
ingredients and
say okay mix those together
or something
but I'll see how much time
I have I've
been working a bit on the
firmware in
the UI and I think I'm
going to use
processing org for the UI
just because
it's so quick and easy
I've already got a simple
GUI over there
and if I put some pressure
on the scale
you can see it's already
feeding the
values through the serial
port into the
computer there so I'm going
to come up
with a simple packetized
serial protocol
and the computer will
basically be
driving microcontroller
it'll send
commands like you know
dispense five
grams of flour and then the
microcontroller will handle
the loop
between the the motor drive
and the
scale and then send back in
okay and
probably what will happen
is you know
the target value will be
five point zero
zero grams and it'll
actually get five
point zero five or whatever
end up
getting and so the
microprocessor can
connect and send the actual
value back
to the GUI so all the
stations here have
been tested except for the
brown sugar
and the chocolate chips and
the baking
soda so once I get those
straightened
out I'll be fairly
confident that I can
dispense you know about the
right amount
of each material and do
that in a fairly
controlled manner you know
with the
computer and all that stuff
working I
think that'll be just fine
the major
uncertainties left are the
mixing like I
say it might be done by a
human and the
mechanics involved with
with moving this
carousel around I'm
planning to attach a
grey code to the side of
this white
Delrin collar here and then
put a
four-channel optical reader
on there and
then drive this around with
just a DC
motor and implement another
servo loop
in the microcontroller I
don't think
that'll be too hard I think
that'll
actually work out fine and
seeing this
thing whip around
automatically will be
impressive okay see you
next time back
s
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