Hottop. Filth, stripping and manual stimulation.

Roasters and roasting

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Postby lsjms » Sun May 09, 2010 10:20 am

Your control sounds ideal. I too have the BT & ET thermocouples in, the bean temp is not much use to me, tend to watch the environment temp and sniff/look/listen to the beans. The model P sounds as bad as the v2003, it too would just decide the beans had reached a certain point and act as it saw fit. You could get round it by tuning the weight of beans but on the coldest nights in winter that could be as low as 140g.

The agitation is good and very even but beans often get stuck in mine, I would also like a little more chaff removal for lighter roasts. More violence in the beans would help this I think. I also reckon with bigger vanes you could do more coffee/quicker roasts as the beans would fall through the hot air rather than the wavy, flowing motion they do now which seems to make for slow drying times.
Following this;
http://www.home-barista.com/home-roasti ... 14069.html

After that the only thing to tinker with is ducting the fan out the top filter so it extracts better and I have a fighting chance of being allowed to roast in the house next winter.
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Postby bruceb » Sun May 09, 2010 2:47 pm

lsjms wrote: After that the only thing to tinker with is ducting the fan out the top filter so it extracts better and I have a fighting chance of being allowed to roast in the house next winter.


If you have a way to get a 100mm flex pipe out of the house (window?) you can build a simple box to place over the whole roaster, put a 240vac fan in the top and couple the flex pipe to it via a clothes dryer feed-through. That will guarantee smoke-free roasting.
Three Francesconi (CMA) espresso machines - Rossi, San Marco, LaCimbali, Faema and 2 Mazzer Major grinders- CoffeeTech Maggionlino, Hottop, Alpenröst and HW Precision roasters.
I decided I needed a bit of a change so I roasted some Monsooned Malabar. That was a change!
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Hottop computerisation

Postby Paksong » Fri Jul 09, 2010 9:37 pm

[quote="GreenBean"]The version I am using with computer control requires knowledge of electronics to connect the Arduino and thermocouples (which are built into the Hottop) and requires breaking into the control signals in the Hottop. I do not expect many people would want to do this. If anyone does they are welcome to a copy of the software.[/quote]

Hello GreenBean,

It would be wonderful if you could let me have a copy of your firmware/software, and more information about how you interface the Arduino. Do you use the Hottop control panel at all (i.e. shared control), or do you control the hottop 100% from the computer?

On my KN8828 (as you probably know) there is a cable from the control panel to the main board with what seem to be mostly TTL signals at about 5V, which determine whether to turn the heater, drum motor, cooling motor and solenoid on or off. These should be very straightforward to connect to the Arduino. The fifth signal for the fan is a little more complicated, as it has 4 different voltage levels for different fan speeds; maybe the darlington array just creates different drive voltages for the fan from the different input voltages, but I am not quite sure. On your P it is probably quite similar, is it? What is the sixth signal on the signal cable?

What I was thinking of doing as a first step is simply to put the Arduino inline in the signal cable with controller outputs as inputs and with the Arduino outputs controlling the mainboard. Then I can get the Arduino to show when the built-in controller is switching things on and off, and at the same time allow a manual override at any point, and send all the results to a computer for recording. That is just the first step, later I want to take over complete control. I was also thinking of doing a completely new ventilation system, eventually. Is your setup doing anything similar?

[quote="GreenBean"]... connect the Arduino and thermocouples (which are built into the Hottop) ... .[/quote]

By the thermocouples I assume you mean (1) the built-in sensor, which appears to be an NTC thermistor isn't it? and (2) a thermocouple which you have added yourself to get a better measure of bean mass temperature. Like the KN8828, the P only comes with the one sensor, doesn't it? When you mentioned environmental temperature above were you referring to the Hottop's built-in sensor on the end wall of the roasting chamber, or have you added another thermocouple somewhere? Do you have meaningful readings from the original hottop sensor? By that I mean calibrated temperature readings that are comparable to the bean mass temperature. Do you find it useful to have both?

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Postby GreenBean » Sat Jul 10, 2010 9:06 am

Hi Paksong,

I have added an Arduino controller to a Hottop B and P model. Earlier Hottops use a completely different control and power board and, no doubt, use different control signals.

The Arduino controllers read temperature data for bean and environment temperature from two thermocouples I have installed through the back wall of the roast chamber. The thermocouples are interfaced to the Arduino using MAX6675 chips. I do not make use of the thermistor reading. The Arduinos can be arranged to autonomously control the roast via software PID etc. They can also communicate with an external computer via a USB cable. All state information from the Arduino is passed to the computer and commands can be sent from the computer to the Arduino for power level, PID parameters, etc. I prefer controlling via an external computer where I can log and chart the profile as the roast progresses.

I consider that the P and B models already provided adequate control for everything but heater power control so I have only broken into the heater power signal.

PM me with your email address if you want me to send a copy of the Arduino software I am using.

For your information I copy below the first part of my Arduino sketch which provides further information on the Hottop control signals (for the P and B models only) and the Arduino/computer interface.

/****************************************************************************
* Arduino control of a Hottop roaster by Tom Coxon
*
* Sends data and recieves instructions as key=value pairs.
* Sends temperatures T1 and T2 at sendTimePeriod intervals as "T1=123.6"
* Accepts instructions for power level, set temperature etc.
* Example: Send to Arduino "power=80" or "setT=240.6"
* For a full list of available commands for PID control etc. see the
* doInputCommand method below.
****************************************************************************/


/****************************************************************************
*
* Connections required to Arduino and Hottop:
*
* 1. Break into Hottop call for heat connection between control and power boards
* 2. Connect both to opto isolator transistor with correct polarity
* (control board to emitter, power board to collector)
* 3. Add switch to Hottop across call for heat signals. Close to return to original Hottop control
* 4. Add LED with 1 K resistor to Hottop across call for heat to power board and Hottop +5V
* 3. Connect pwmPin to opto isolator cathode and a 10 K pull down resistor between cathode and ground
* 4. Connect opto isolator annode to 5 volts via 1 K resistor
* 5. Connect thermocouple boards to pins 3 - 6 CS1, CS2, SO & SCK
* 6. Connect thermocouple boards to 5 volts and ground
*
* Hottop Control board connector:
*
* from the outer edge of the board inwards:
*
* GND / 0V
* +5V
* FAN (both drum and cooling fans, PWM control on newer models)
* EJECT SOLENOID
* MOTOR2 / AGITATION
* MOTOR1 / DRUM
* HEATER call for heat signal (PWM control)
* INTERRUPT ("P" / "B" models only, pin not present on older models)
*
* These are all 0v/5v based logic signals
*
****************************************************************************/

/****************************************************************************
*
* Control options.
*
* 1. Manual as original by closing switch
* 2. Arduino control by opening switch can use PID or other algorythm
* 3. Computer control by sending commands to, and receiving state
information from arduino
*
****************************************************************************/
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Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Dalian 1 kg roaster | Hottop P | Hottop B | French Press (several) | Kettle modded, no really, added digital thermometer |
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Postby Paksong » Tue Jul 27, 2010 11:19 am

[quote="GreenBean"] * 3. Connect pwmPin to opto isolator cathode and a 10 K pull down resistor between cathode and ground
* 4. Connect opto isolator annode to 5 volts via 1 K resistor/[/quote]

Hello GreenBean,

Many thanks for all your info, which I have been slowly starting to digest. I realise though, that I am going to have trouble understanding the program until I have an arduino to experiment with. I've just ordered one from HK but it will take a few weeks to arrive.

Why do you connect your signals directly to the optocoupler? Surely you should be able just to plug the Hottop control cable into the arduino and a second cable from the arduino into the control cable socket on the main board. The Arduino should be able to read whatever the Hottop control panel is saying (and send a copy to the computer if desired), and either forward it directly to the main board or override it according to its program. Is there any reason why this should not work? On the control cable there are only TTL signals switching on and off, and the main board switches the load accordingly. As far as I can see this should still work for PWM, as long as PWM is implemented on the main board (I have a later main board for my analog model, which appears to have PWM capability for the heater, although the analog control panel does not use it). On your P the heater is switched by a BTA16 triac, which in turn is driven by an IS6015 optocoupler. On my main board the heater is also switched by a BTA16 triac, which is driven by an MOC3023, which in turn is switched by the control panel cable through the ULN2003AC. I should have thought the PWM signal should be able to go through all that, since we are not using any high frequencies.

What is the Interrupt signal doing on the P? Is it giving AC rise and fall times for triggering the PWM? I notice that P has an extra 2 optoisolators on either side of the transformer - is the interrupt signal connected to these? On my main board I have a 7-pin connector, but on the PCB there is an 8th pin which is connected directly to the diode bridge from the transformer (without any optoisolator).

How does the PID control the temperature? I saw the PID target temperature being set to 220 Celcius by default, as though it is homing in on that target temperature from the start of the roast (which I would not consider desirable) - but presumably the main program is a lot more complicated than that. Are the three programs you sent me combined into one firmware on the arduino?

Do you have a program running on the computer, or just a communications link that forwards commands from the keyboard?

Regards
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Postby GreenBean » Tue Jul 27, 2010 5:33 pm

I do not have the time to answer your questions in full but in summary I chose to keep the Arduino electrically isolated from the Hottop. There are many ways you could approach this. I included information on how I have connected it to aid in your understanding of the code for the Arduino.

As I have already stated in this thread I prefer controlling via an external computer where I can log and chart the profile as the roast progresses. All state information from the Arduino is passed to the computer and commands are sent from the computer to the Arduino to set all PID and/or other parameters before and/or during the roast.

I have sent you the Arduino sketch (the main program) and the two libraries it uses which you will need to compile the code.

I suggest that you use email for any further questions as this level of detail is unlikely to be of interest to others.
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Izzo Alex Duetto | Gaggia XD 2 Group | Mazzer Super Jolly | La Cimbali Max | Solis 166 | Dalian 1 kg roaster | Hottop P | Hottop B | French Press (several) | Kettle modded, no really, added digital thermometer |
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Postby lsjms » Wed Jul 28, 2010 3:44 pm

Seconded, I mean where's the filth and manual stimulation. I keep clicking on this thread thinking perhaps someone want to know how to throw a circuit board in the bin or has found a hottop dirtier than mine. Instead I find shame at not understanding what the f*** you guys are talking about :lol:
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Postby Belgik » Thu Oct 21, 2010 4:22 pm

lsjms wrote:I find shame at not understanding what the f*** you guys are talking about :lol:


I today roasted for the 228th time since 5 Jan 2008 on my 7-step manual hottop, took the basic bodywork off for the 4th time, cleaned it up and washed the drum and some other parts a bit, and screwed it back together. I'm so pleased with the simple mechanics (NOT mentioning the electronics, though!) that I sent Chang Hue a "thank you" email. The basic build quality is fine, the coffee (at 200 grams a roast) is great and ...well... given my finances I hope the machine stays alive for at least another five years.

Who stocks spares in Europe for the Hottop nowadays? I bought mine from Hasbean, but he seems to have moved on to other roasters...

Cheers,
Paul
ECM Giotto maquinas, Macap M5 grinder, reconditioned Zassenhaus manual grinder,
Thor tamper, Britta filtered water, cheap vacuum cleaner, Hottop "basic" roaster, green beans in stock.
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Postby lsjms » Tue Nov 23, 2010 12:23 pm

Sorry for the slow response.

You can get in touch with Hottop USA directly, Shelly handles the parts service in the UK. They a very responsive.

No idea how old my Hottop is, is was sold by Has bean in the North to a guy in SE London, he sold it to a Yorkshire TMC member in 2007 and I brought it back to SE London about a year ago. The bean door is playing up, apart from that it's tip top. 5 years should be no problem- they are tougher than the sum of the parts! I eliminated the need for a cooling cycle and did over 5 kilos in a day.
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Postby bruceb » Tue Nov 23, 2010 1:45 pm

My original Hottop that was converted to the digital (not programmable) model a few years ago is now 5 years old and has well over 1000 roasts under its belt. I have completely disassembled and cleaned it 4 times, but never change the filters (just one time to see whether it made a difference and because I happened to have a spare). Aside from a control button (membrane switch) becoming unresponsive and requiring the control panel to be replaced under guarantee I have had no issues with the machine at all. It is very sturdy and well made.
Three Francesconi (CMA) espresso machines - Rossi, San Marco, LaCimbali, Faema and 2 Mazzer Major grinders- CoffeeTech Maggionlino, Hottop, Alpenröst and HW Precision roasters.
I decided I needed a bit of a change so I roasted some Monsooned Malabar. That was a change!
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