Making the BEHMOR computer controlled

[ben_neufeld]

Hi Coffeesnobs, Andy, AM and any other tinkerers.

I have a Behmor 1600, like many of us on here (although i sourced mine elsewhere coz andy didnt have any stock....)

Anyway, ive been contemplating how to mod the behmor once the warranty expires so as to make it as programmable as possible.

i stumbled upon this product and it appears to be a fantastic solution.

http://www.thesiliconhorizon.com/reflow.htm

It appears to be a firmware based PID with a k-type thermo couple with both oven and fan control. It has USB onboard, and there is software available to create your own profiles and monitor in realtime.

I was wondering what you guys think, my concern is that to control the oven it simply has a trigger for a relay (and the on/off/on/off may not be great for the heating element although i understand thats how the behmor operates anyway)

Andy, is there any way of integrating some of their software or this hardware into your roast monitor soft.

This product would appear to be the definitive step in making the behmore one of the best home roasters around

Let me know your thoughts folks.

[A_M]

Re: Making the BEHMOR computer controlled

This product would appear to be the definitive step in making the behmore one of the best home roasters around  

The Behmore already is... It just that some of the functionality etc is being further developed..

Now use this unit to control the Heat and the Fan on a KKTO and it would be very interesting...

Still requires careful attention to what is driving what a the board is Low voltage and drives low voltage  thus any number of SSRs to then actual switch the heater  and or fan..

So a couple of hundred $$$ to start with...

Toss in an Electronics Eng and an Electrician to validate and make sure it is all safe...

1: Would breach the Behmore specs and validation..

2: Would mean breaching the TO specs and thus the KKTO becomes another electrical mess - if being done by the home DIY person


It could be an option to further mod any number of systems... But with all the extra costs and risks.. Is it viable...  

Depends... Quest M3 needs some extra  

Besides... The KKTO is fine as it is..    Precision controllers for mass production and consistency where being run by casual staff...

That why good roasters are good.. They are  artisans of a special kind  ;D

PS... Coffee by numbers... Na... that why 2 + 2 = 5  

[beanflying]

Re: Making the BEHMOR computer controlled

Hi Benny,

I have the reflow board from Silicon Horizon (got it last year) and am currently playing with it to add to my Hottop now I have started hacking the current electrics. More to follow over winter as I get some more spare time.

[ben_neufeld]

Re: Making the BEHMOR computer controlled

Further reading highlights that it only has the ability to switch the fan on or off.

Does the behmor vary fanspeed throughout a roast..? Ive never heard it change pitch..

I cannot wait for Mr Behm to update it, but full computer control would be marvelous..

Im fully aware of the implications of modding anything electrical. Was more Interested in opinion on whether the product would be viable..??!

[A_M]

Re: Making the BEHMOR computer controlled

Im fully aware of the implications of modding anything electrical. Was more Interested in opinion on whether the product would be viable..??!

Any thing is Viable... Just define the context....

If ya look at teh KKTO and the behmor not cost effective; if ya look at the base cost and then all the extra.......

[beanflying]

Re: Making the BEHMOR computer controlled

Fan control is an issue but it is not unsolvable, the Solar Roaster (2kg) uses a series of full speed fan pulses to control airflow rather than varying fan speed, while the Hottop D in standard form varies the speed throughout the roast. So both work but judging how much and when is part of the equation or even if some additional timed control is required triggered by a pulse from the board that would normally just turn the fan on or off.

At this stage I am just leaving fan control as fully manual while I play. Before putting anything up here I also want it well sorted and tested to make sure it is working well and is safe and has some very clear details.

Not labouring the point here but there is to little electrical knowledge here on a coffee forum for most readers to be playing with 240V gear. If it was a dedicated electronics forum I would treat it a bit differently.

[ben_neufeld]

Re: Making the BEHMOR computer controlled

The board could be had for $100, add enclosure, relays, etc all up $200..

To give it the usability of the hottop d or whichever the expensive one is, seems good to me..?

So in my opinion cost wise its viable. Does the product seem useable..?

[beanflying]

Re: Making the BEHMOR computer controlled

The D is the earlier and cheaper one (the one I have), P is the exe one but the B Hottop is the currently the most flexible one and none of them are anything like this for control.

As to usable yes it is as to if it is the perfect solution then no it isnt. Some firmware mods might make it that way but thats for further down the track. There is plenty of other boards (Arduino and others) on the market that are more flexible but they didnt have any code as a basis to start using them so I got one of these.

As to doing all this to a new Behmor and voiding any warrantees then that is up to you but I would consider the Behmor what it is a good entry level roaster that is easy to use in its current form. Nothing wrong with modding it but consider will it make better roasts over the current programs if you do or will its design limit improvements making a KKTO or Coretto or Hottop a better basis for the board?

[A_M]

Re: Making the BEHMOR computer controlled

Not labouring the point here but there is too little electrical knowledge here on a coffee forum for most readers to be playing with 240V gear. If it was a dedicated electronics forum I would treat it a bit differently.

So true..

I like the  Varying fan speed  Vs  Pulse control - All variable (how ya do it; is the thing )  

Does the product seem useable..?

For what...  If you think so, great... I have already stated ... That I do not..

The board could be had for $100, add enclosure, relays, etc all up $200.

WHERE did you get those $$ from..  As stated above...."there is too little electrical knowledge here".   If I was at work and had access to all the bits at a great price... Would play....

To buy quality items/parts etc  and have no need for the product.. Not worth $0.50 to me... But could be worth every cent of $300 to some one else....  

Will it add $300  worth of quality to 15min with my roaster.. No.


As a project for self interest in control systems.. NO....  Not really... Go and do a course that is focused and then the traps will become more relevant..

Now just go a use a basic PIC chip and be done with it  ;D

[beanflying]

Re: Making the BEHMOR computer controlled

Varying the fan on a Hottop is easy as it is 12V DC so whatever method is safe and easy (currently using a variable power supply for playing). A PC cooling fan controller might work but they are normally used on smaller fans and I cant find a power rating on one. Other option is to set up a simple chopper using a fet or a baby SSR and a 555 timer. If the Behmor is built like other small ovens then the fan may be DC as well.

On costs I am working on $250 to 300 with all the bits. If I wanted cheap and easy then I would have brought the "B upgrade" and been happy but tinkering appeals to me .

[A_M]

Re: Making the BEHMOR computer controlled

On costs I am working on $250 to 300 with all the bits. If I wanted cheap and easy then I would have brought the "B upgrade" and been happy but tinkering appeals to me .

ARRRR and there in lies the driver..

Upgrade (A) or Personal path to Upgrade (P)..


Thus looking at A vs P for costs; then even if P is a little more... The experience and the End that is to be achieved is what justifies the project and teh cost differential between A and P..


PS... Let us know how it goes..

I always reckoned a Laptop and software (LabView or Lab Windows ) and some basic I/O hardware would be cheaper......

Assuming the Laptop is off the foot path (clean up week) and you have a student version of Lab-windows ;D

[Dimal]

Re: Making the BEHMOR computer controlled

Way too many variables to consider where coffee roasting is the aim. And like bean says, if this was an electronics/engineering forum then more could be discussed and suggested in appropriate terms.

Personally, I dont like binary output control for something as tactile as roasting coffee; much better to use a variable output device feeding into a PWM driven heat source. Binary control is more suited to where physical mass supplies the necessary damping to facilitate accurate temperate control of the process.

All the best,
Mal.

[beanflying]

Re: Making the BEHMOR computer controlled

variable output device feeding into a PWM driven heat source.

Just started breadboarding up one of these last night to go with the Reflow board. 556 Timer chip used as a PWM to an SSR on one side and the other as a PWM to a Transistor at this stage to run the fan on my Hottop. This is designed to be a fully manual mode of operation but it will still incorporate the safety features and the cooling cycle of the D model Hottop in the long term. While this is really simple low voltage electronics it still involves hacking the high voltage side of an appliance and putting in some additional switching on 240V. Roasting with this in the next few days. It will be nearly like going back to the Bowl and Spoon for ease of control ;D

I still intend using the board mentioned above and the dry (no beans) test run I did with it seemed to run OK with full fan on but before any beans go in I need some sort of fan control as above. This mode if it works correctly will be temp following on preset profiles using the board as a PWM to the SSR with user controlled airflow at this stage using the 556. Hope to have some semi auto beans out of it in the next few weeks time permitting.

Apart from these details until it is all finished tested and safe I dont really want to put up circuits pics etc but for those that know about electronics that should be plenty to have a play too.

[Dimal]

Re: Making the BEHMOR computer controlled

Sounds good bean... 8-)

Do you know what the hysteresis of your SSR is? The duty envelope of this will determine the maximum switching frequency of the PWM.... The higher the frequency the better of course

Mal.

[WSullivan]

Re: Making the BEHMOR computer controlled

Updates guys?