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MAX HEATGUN MH-1 HRO edition
JETROASTER
So, here's where we begin an open-source build project. Initially, it will be based on a very basic air-roasting platform. Easy to find parts, easy to replicate.

The larger mission for me, is to stimulate innovation/expansion within the community that has the greatest sense of responsibility around coffee.
Home-roasters/micro-roasters are more likely to make responsible coffee purchases, so that's the group I'd like to see expand.

Beyond that, it's evolution will be driven by all those that participate.
My basic contribution will be the airflow and heat source. It is called the MAX HEATGUN (because that's all it really is). It's the MH-1(1 lb capability) and it will be the HRO edition because others have joined the fray for this joint project.
The HRO edition will be a great learning experience as a joint build. It will then be auctioned off (if deemed worthy by the group) for a great cause.
.....More coming soon. Scott
 
jm82792
I can help you out with a simple arduino controller(using a out fo the box arduino...) that would emphasize simplicity and being economical.
 
JETROASTER
Hi jm,
Bill (bvwelch) is on-board to lead that part. I think he's a busy person like everyone else, so there may be room for getting in to help. I'll send him a PM and get his feedback. Thanks for jumping in! -Scott
 
jm82792
I'm not extremely good but I can get it up and running.
I am not experienced with getting boards milled,
prototyping or such. Primarily just code(well it's Wiring, it's considered easy by most standards) and basics.
But when you've monkeyed with an Arduino for a year you learn enough to be sufficient.
But since it's open source, simplicity and being cheap are king.....

 
JETROASTER
The main vessels for this roaster;
http://www.google...DcQ8wIwAg#
.....or something similar. Both ends will need to accomodate a 1.75" opening.
Although they are a bit narrow (just below 5"dia), they had the right general shape, and they are certain to be food-safe.
The cocktail strainer that is built in will become the distributor/perf plate.

I'll continue adding to the scavenge list. -Scott
JETROASTER attached the following image:
max_vessel.jpg

Edited by JETROASTER on 03/07/2011 4:40 PM
 
allenb
I think this will be one of the more interesting open source projects! It will be exciting to see the roaster evolve with contributions from many here at HRO.

Were you successful with gaining more heat from your element?

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
greencardigan
Scott, there's heaps of shakers on eBay. Is there some way of knowing which ones are suitable? Or am I getting ahead of myself?

What about this on for instance?

http://cgi.ebay.c...5920wt_922
 
JETROASTER
The ones I'm using are about 1700ml. I would prefer something just a touch wider,but it's not a deal breaker.

Allen, the heat; I've tuned the motor in at 18" lift on the intake side, leaving me with 10" of pressure @ the plate. (11.5" with heat). It's just above minimum fluidization velocity. I've got 375f throughout the RC (no beans).
.....So that's it, after this test, I'll have to snip to get more heat.
Tomorrow ....beans. -Scott
 
jm82792
I'm interested in this design once it's usable.
I've been bouncing around, and in the end simplicity(+easy to find parts) wins along with easy to build.
 
JETROASTER
A little something for the shopping list; http://www.fixtur...95131.html
(the pricing on that link is some sort of joke)

I'm currently using 2. One for the exhaust fitting, the other is used as the inlet to the R/C, and also serves to fasten the entire central yoke together. A fairly important piece.
I found them in Lowes plumbing section @ 7.99$ U.S.
They both get altered slightly. I also retained the little handle on the strainer. I've used it to secure the heat coil in place.
-Scott
JETROASTER attached the following image:
drain.jpg

Edited by JETROASTER on 03/12/2011 9:28 AM
 
JETROASTER
Adding to the shopping list;
Heat element; http://www.graing...Pid=search

About 4 wraps if nichrome get removed.
JETROASTER attached the following image:
element_1.jpg
 
JETROASTER
....And 2 of these;
JETROASTER attached the following image:
barrier_block.jpg
 
JETROASTER
...And look for one of these under a variety of names. (Eureka, Fuller, Shark) They contain a 3" blower. -Scott
JETROASTER attached the following image:
mini_vacuum_cleaner.jpg
 
seedlings
Do the cordless models use the same blower?

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
JETROASTER
Sorry, those are all DC motors. ....Not quite the same kick. I have started playing around with those. They seem more controllable (electronically).
....Something in the future .....
I had to restrict this 3" blower a bit to make it behave, so with that in mind...there are some little DC blowers that could work. I think one pound might be the upper limit, but certainly worth looking at.
I really wouldn't want the nuisance of recharging, so how might one incorporate a DC motor into an AC design? - Scott
Edited by JETROASTER on 04/22/2011 1:37 PM
 
seedlings

Quote

freshbeans wrote:
Sorry, those are all DC motors. ....Not quite the same kick. I have started playing around with those. They seem more controllable (electronically).
....Something in the future .....
I had to restrict this 3" blower a bit to make it behave, so with that in mind...there are some little DC blowers that could work. I think one pound might be the upper limit, but certainly worth looking at.
I really wouldn't want the nuisance of recharging, so how might one incorporate a DC motor into an AC design? - Scott


Depending on the current draw, you could find a wall-wart in your junk drawer that might do the trick... might even grab one with more or less voltage as needed...???

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
allenb
Another option would be to use a bridge rectifier like this one with 1/4" connectors: http://parts.digi...e4-51.html

You would also need a suitable wattage resistor to drop the voltage to match the motor and place it somewhere upstream within the air path for heat rejection.

This wouldn't take up much space.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JETROASTER
....Using the bridge rectifier approach.....I think I've got a motor that has just enough kick. It is 15vdc, 200ma.

What would the wiring diagram look like, if it included a manual speed control? Thanks,Scott
 
greencardigan
Are you sure it's only 200mA? That sounds too low for 15V.
Edited by greencardigan on 04/25/2011 7:02 PM
 
allenb

Quote

greencardigan wrote:
Are you sure it's only 200mA? That sounds too low for 15V.


I agree. 2/10's of an amp seems low for a motor capable of lifting even a half a lb.

As far as a wiring diagram.

This circuit works real nice for up to 25 vdc and up to 3 amps. It uses a small rotary pot to dial voltage level. If using a transformer, use one with a secondary voltage not much higher than the motors max voltage. For a motor not drawing more than an amp the transformer would not be very large. As mentioned earlier, you can also use a dropping resistor.

http://www.nation.../LM350.pdf

Scroll to page 7 in the data sheet, top left of page. Use the LM350 not the LM150. Mount the LM350 to any sheet metal nearby for heat dissipation.

Allen
Edited by allenb on 04/25/2011 8:38 PM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
allenb

Quote

allenb wrote:

Quote

greencardigan wrote:
Are you sure it's only 200mA? That sounds too low for 15V.


I agree. 2/10's of an amp seems low for a motor capable of lifting even a half a lb.

As far as a wiring diagram.

This circuit works real nice for up to 25 vdc and up to 3 amps. It uses a small rotary pot to dial voltage level. If using a transformer, use one with a secondary voltage not much higher than the motors max voltage. For a motor not drawing more than an amp the transformer would not be very large. As mentioned earlier, you can also use a dropping resistor.


http://www.nation.../LM350.pdf

Scroll to page 7 in the data sheet, top left of page. Use the LM350 not the LM150. Mount the LM350 to any sheet metal nearby for heat dissipation.

Allen


The secondary of the transformer or dropping resistor feeds the ac input to a bridge rectifier. The dc output of the rectifier feeds the input of the LM350.
Edited by allenb on 04/25/2011 8:40 PM
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
greencardigan
I have used a ceiling fan dimmer -> transformer -> rectifier to power a dc popper motor. This didn't require any soldering other than the inline fuse holder I used.
 
allenb

Quote

greencardigan wrote:
I have used a ceiling fan dimmer -> transformer -> rectifier to power a dc popper motor. This didn't require any soldering other than the inline fuse holder I used.


Cool, this is a whole lot simpler than my circuit and would be plug and play.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
JETROASTER
It sounds like the variable setup would be a great way to try a few motors and find a winner. After that, a simpler setup could be determined.
The one motor I've got is unmarked , the 200ma 15vdc was the only numbers I saw on the wiring diagram.
Being able to try a few would be great.....
Allen, or GC,would either setup cover a wide enough range to test a variety of motors and find a potential winner?
- Scott
 
bvwelch
Both circuits have a lot and common, and should allow for experimenting with various motors.

Both need a transformer and a diode rectifier to step down the AC voltage to a low-voltage DC.

Allen's approach uses a circuit on the DC side to vary the final voltage. GC's approach uses an AC dimmer to vary the input to the transformer.

Be sure to get a transformer that can handle a 2 or 3 amps. Likewise the rectifier. While you can make your own with 4 diodes, the pre-built "full-wave bridge" rectifiers are inexpensive.
 
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