I’ve had a few conversations by email with the author of VGDD. He has quite good English knowledge and we’ve come up with a few background similarities that has made it pretty interesting to discuss the product here and there. A few times I’ve mentioned something I’ve done by modifying some of the files that came with the program or discussed something I’d like to see and it turns out he just did it in the next version he’s releasing in a day or two or intended people to be able to do what I had done in a future version that could fully support it easily.
Most of the time we’ve talked it’s been because I’ve looked at the PIC32 sitting on the table and I keep thinking of how I really need to get that touch screen going. I then sit down and update the program and end up building a bunch of screens and compiling things and discover a bunch of weird little bugs and he quickly fixes them and releases a new version.
A couple nights ago I roasted 4 batches of an Ethiopian coffee and found a couple more glitches in my Arduino roast profile and the cooling cycle but it’s getting better. It got me thinking about VGDD again, which I had upgraded to 5.0 a few weeks back, and it turns out there was a 5.1 version now. This time he’s now included TechToys Ultima R4.1 board that includes an SSD1963 controller on it. If you haven’t looked at it before this board accepts a Microchip PIC32 Starter Kit board and has a variety of other things built on such as the SSD1963, an MP3 Decoder, a footprint for a wireless network card and a few other connections. Combined with a 7 inch touch panel it’s about $139 + tax right now. It seems to be an excellent product but I just think that it was a move in the wrong direction to squish so much into one board. Instead I would have rather it been made to be modular to let you enable/disable sections of it to use those pins in your own ways. I’ve been using the SSD1963 EVK 3B board hooked to my PIC32 expansion IO board for the initial testing I’ve done. It ends up around $99 w/ a 7 inch touch screen.
My early little touch screen using Microchip brand boards was a lot more money and to get a 7 inch screen today with the new Epson controller would be about twice what I spent for the SSD1963. The original little screen was pretty good to see what the roast was doing when I first started trying to build a coffee roaster but it was just too small. This is why I started trying to build a 7 inch touch version of my roast controller which allowed a whole lot more to be done on the screen.
While I had gotten the SSD1963 working in some of the older VGDD versions by hacking the XML files I was not having the same luck with 5.0. With version 5.0 of VGDD I kept getting errors when I compiled and had issues with the screen not working as I expected when I finally got it to compile and I didn’t have a lot of time to work on it. Seeing SSD1963 in the Ultima board being supported in 5.1 I figure I just need to ensure I configure the wiring from the EVK board I have to mimic that of the Ultima board I should be able to get it to compile.
Lately (on the Arduino side) due to some changes with the serial output of the project and my attempts at adding more functions to the processing GUI I’ve found that I’ve managed to break the PID/LOG communication to the processing GUI and forgot to commit a copy to my home code repository server and there’s too many changes to really figure out which area got messed up without a lot of work. As a result that lack of visualization is really starting to become an issue so I’m really going to start trying to develop the PIC32 side more to at least process the output of the Arduino and run the touch screen to display it all.
I’m oncall for work this weekend but I hope to be able to verify the wiring with the Ultima schematic and make sure I cable up the EVK board properly and get a screen or two going again using VGDD. I’ll post the wiring info once I get it going.
So I’ve played around with the PID settings. I haven’t officially sat down and tried to do a “real” tuning since the processing app I’m using right now lets you play with different numbers and feed it back to the Arduino to tweak it. As a result I came up with a few numbers that flattened out a lot more than it did previously.
First roast with crudely adjusted PID
Next I will need to take it more seriously I wipe out the configurations, dump some junk beans in, and fire up the roaster and calibrate until I can’t stand it anymore and then roast some coffee again.
In regards to the button controller I have figured out a layout that I will likely use but I’m trying to keep this accurate on the schematic system I’m working with to build a real PCB later. For whatever reason the part in the system appears to not match every other part I’ve seen out there and what I’m currently working with. I also need to go back to radioshack and buy a resistor I’m going to need because the big multi-pack I have doesn’t include that one resistor that I need to make the math work.
The last couple roasts with this new controller turned out decent enough. After 3-4 days rest they had extremely good smells (but tasted only “pretty good”.) Today’s two tests are MUCH closer to ideal roasting the way they worked out and the smells (and the smoke detector) agreed at the right times. I’ve got two batches waiting that will get consumed over the next several days and we’ll see how it’s going as they rest. I’ve got a single serve coffee brewer that’s working out better than some of the other ones so it will take me some time to work through all of the beans.
So as some of you may have guessed with the gaps between postings I have way too many hobbies. One of them includes aquariums. I only do freshwater stuff but I do more than “a goldfish in a bowl”. Really I mainly focus on plants, shrimp, and a few not really extreme fish that are deemed compatible with the shrimp. The plants need lots of light to make them grow which is why most people can’t keep aquarium plants alive. The shrimp pick at the base of the plants pulling away the dead parts and look cool.
Several months ago I had some setbacks with some shrimp and some illnesses that came in with them. I’ve decided to start over and build a setup that is designed to keep all of the conditions very solid that was hard to do in the “nano tank” that I had been using. This resulted in ordering a new tank that came with a matching size stand that was unfinished. I had to sand, finish, and assemble a stand and I’ve been throwing together a bunch of automated controllers that monitoring a variety of probes and adjust things…. not much different than controlling conditions in a coffee roaster. Eventually I’ll be building my own control system for it and I’ll be selling off the existing control system that I’m installing just to get it running.
There is obviously value in “get it done now” vs building it yourself. There is always a cost to results ratio that needs met to justify buying something or doing it yourself. I think a lot of the coffee roasting world in the DIY arena operates in this world. For people who cannot do it themselves and insist on programmability etc there are 800-900 dollar roaster systems. For everyone else there is 150-500 dollar roasting setups. Finally for those that want to make a 900 dollar roasting system on their own there’s Arduino and other micro controllers and the $9.99 Poppery roaster to the $200 random brand entry level roaster.
Anyway, I’m at a stage with the roaster that I need to hook up relays to cycle the heating systems on and off. I’m probably going to order a second SR500 base from a site I found on the internet to take apart completely and splice these relays into it for the microcontroller to cycle. I’m pondering the 3 stages of heat from the selector switch and actually cycling the power to the heater element. I need to check some voltage readings from inside the roaster once I take it apart and decide if I want my controller sending signals in place of the switch to vary the desired heat status or just control the heater. It might be easier to try controlling the fan speed first from my controller and then come back to the heater later.
For the moment I need to finish the fish tank stuff. This weekend I’m trying to finish the under tank plumbing and then get the tank up on the stand. The tank is an 18x18x18 25 gallon glass tank (no plastic, only a silicone seal between the glass). I’m using a Neptune System Apex Controller underneath and am running all the sensors into the plumbing underneath. The light on top is a 70 watt Metal Halide and the I’ve got CO2 gas bubbled into the plumbing based on the pH. The entire thing gets logged and can be graphed onto a device web page. I’m using an Eheim Ecco canister filter and running the output through a UV sterilizer, inline heater, and the CO2 reactor. Later (once I get the right fittings) I’m mounting a IceProbe chiller inline through some plumbing as well. I need to modify it with different fans to push air from inside the enclosure through the heat sink and then vent it out of the tank rather than blowing air down onto the heat sink. The fan is pretty noisy so I’ll be replacing it with fans used to make super silent computer vent fans and running a series of small ones along the sides blowing inward and one large one up top to suck outward that will pass through the base enclosure wall.
I’m kind of discouraged in the coffee world right now. Mainly I’ve been waiting for a good Ethiopian coffee to come in but this year has not been a good year for coffee. I’m trying to figure out what else I want to try as my “base” coffee for the ongoing roasting experiments. I really need to have a base to compare one roast to the next as I adjust the programming on the controller rather than having different beans roast after roast. I just havent found anything I want to drink week after week while I work out the kinks.
So as mentioned previously I took the thermometer probe and used one of those pipe cutters with the “wheel” for cutting things like copper pipe and sliced off part of the probe. Due to the fact that this sort of cutter “crushes” slightly while it cuts this ended up making it so I could not slide the inner electronics out without fear of not getting it back in or damaging it (without having a soldering iron currently). I instead slid all of the formerly connected probe upwards and taped it to the probe’s plug using electrical tape. I then crimped the remaining probe in place at the top against the braided cover.
My initial test seems to have yielded a technically proper heat ramp based on what was happening. Additionally the cooling cycle appears to have been pretty normal too. It appears that when the cool cycle halts the beans are approximately 158 degrees and linger there while in the roasting chamber even when removed from the roaster. They drop to around 130 degrees after being dumped out into another container within about 20 seconds and then they hang around 130-120 degrees for several minutes if undisturbed.
Here is my heat readings for a standard roast. In this case I was roasting the Rwanda Gkongoro Nyarusiza.
Markers are A= Rolling First Crack, B= Second Crack. Fan speed is shown as 100% for the knob being set all the way to the right. 50% is fan knob set in the middle position (straight up).
I was not able to keep track of any additional details due to manually tracking the roast on paper. Cooling with fan speed increased to 100% starting at 6.1 was as follows:
Bean mass started at 120g and reduced to 102g for a loss of 18g or 15%
Java Kajumas Organic Wet-Hulled Initial Roast
- 7.0 to 4.3 – Minimal churn.
- Low Heat
- 100% Fan
- 7.0 = Dark Green
- 6.0 = Medium Green
- 5.6 = Yellow Brown Green
- 5.1 = Cardboard Brown
- 4.3 Single FC – Low churn.
- Set High Heat
- Set 75% Fan
- 4.0 – Chocolate Brown
- 3.8 – Dark Chocolate
- 3.2 – Substantial FC pop
- 2.8 – Rolling FC
- 1.0 – End FC
- 0.2 – Begin rolling 2nd cracks.
- 0.0 – Automatic switched to Cool.
Aroma: Initial aroma grass, popcorn. 24 hr aroma – Sesame Oil, Grass, faint vinegar.
Chaff: Extremely minimal.
Notes: For 4 scoops add approximately .5 to all times.
So I obtained some Ethiopia DP Haile Selassie Sidamo from a previous order made by my girlfriend that I wanted to test as a known entity in the new roaster. We have been drinking Ethiopia DP Haile Selassie Sidamo for the past month or more from a 20# bag order at the end of it’s availability with Sweet Maria’s. We had a previous sampler sized bag of this and liked it and thus bought a large bag of it. Unfortunately, while it was good, it did not taste much like the original that she had had for some time. It was still good but it was not as good.
The new roaster appears to be very comparable for flavors being developed with the SR500 and the Plus 8 regardless of if you are using a lighter or darker roast changing only the roaster being used. The older sampler appears to yield fruity flavor while the new one did not. The new one appears to improve with longer 2-3+ day rest periods. The only thing I can say with this bean is that the flavors must have changed due to differences in the packaging and how it was stored from the original delivery (which IMO appeared to match the review by Tom exactly) and the final order toward the end of it’s availability that seemed like something entirely different. In either case it was good coffee but the original seemed better.
Today having done a basic test roast yesterday of the original and letting it rest overnight I have tasted it black, with sugar, and with vanilla creamers. It seems comparable to what I was getting previously with the Plus 8 roaster. In preparation for tomorrow’s coffee I have roasted two Ethiopia’s for a “Ethiopia comparison”.
Ethiopia DP Haile Selassie Sidamo
- 6.0 to 4.0 – Minimal churn.
- 4.0 to 3.0 – @ 4.0 Turning amber to tan range. 3/4 inch expansion. Medium churn.
- Set High Heat
- Set 50% Fan
- 2.8 – Initial First Cracks reached. Partial brown color. High churn. 2 inch expansion.
- 2.4 – Rolling First Cracks. Full brown color.
- 0.7 – End of First Crack period.
- 0.2 – Initial sparse 2nd cracks.
- 0.0 – Automatic switched to Cool.
Aroma: Initial aroma strong coffee, spice, woody. 1 hour rest aroma including buttery.
Ethiopia FTO DP Sidamo Shoye Union
- 6.0 to 4.0 – Minimal churn.
- 4.0 to 3.2 – @ 4.0 Turning amber to tan range. 1/2 inch expansion. Medium churn.
- Set High Heat
- Set 50% Fan
- 3.1 – Initial First Cracks reached. Partial brown color. High churn. 1.75 inch expansion.
- 2.7 – Rolling First Cracks. Full brown color.
- 0.9 – End of First Crack period.
- 0.3 – Initial sparse 2nd cracks.
- 0.1 – Forced to Cool.
Aroma: Initial aroma virtually non existant. Some light woody and mild coffee smell. 1 hour rest similar to immediate DP Haile Selassie Sidamo.