'Pressure Profiling' With The Fluid-O-Tech TMFR Pump - Or, Wholesale Copying Greg Scace's Ideas - Page 26

#251: Post by **mhoy** » January 16th, 2012, 7:11 pm

Loving seeing an arduino in here. I've got one controlling my Bradley Original Smoker so I don't have to adjust the temp by myself anymore. :-0

Mark

#252: Post by **Jacob** » January 18th, 2012, 1:48 pm

At an early stage I noticed that the flow meter almost always ended up in the same state and I therefore assumed that the contact / no contact states had a very unsymmetrical time of duration (and called the output 'clicks'). But looking at the video (the blinking led in the background) I got second thoughts and I had to make a test reading the state changes instead of just reading one of the states:

*** Shot log ***
00.10 -   1:  56 + 0 =  56 
00.10 -   2:  53 + 0 =  56 
00.20 -   3:  49 + 0 =  56 
00.20 -   4:  48 + 0 =  56 
00.30 -   5:  50 + 0 =  56 
00.30 -   6:  49 + 0 =  56 
00.40 -   7:  55 + 0 =  56 
00.40 -   8:  50 + 0 =  56 
00.50 -   9:  50 + 0 =  56 
00.50 -  10:  48 + 0 =  56 
00.60 -  11:  50 + 0 =  56 
00.60 -  12:  50 + 0 =  56 
00.70 -  13:  47 + 0 =  56 
00.70 -  14:  49 + 0 =  56 
00.80 -  15:  51 + 0 =  56 
00.80 -  16:  51 + 0 =  56 
00.90 -  17:  51 + 0 =  56 
00.90 -  18:  50 + 0 =  56 
01.00 -  19:  48 + 0 =  56 
01.00 -  20:  46 + 0 =  56 
01.10 -  21:  51 + 0 =  56 
01.10 -  22:  51 + 0 =  56 
01.20 -  23:  50 + 0 =  56 
01.20 -  24:  49 + 0 =  56 
01.30 -  25:  47 + 0 =  56 
01.30 -  26:  52 + 0 =  56 
01.40 -  27:  51 + 0 =  56 
01.40 -  28:  53 + 0 =  56 
01.50 -  29:  53 + 0 =  56 
01.50 -  30:  50 + 0 =  56 
01.60 -  31:  50 + 0 =  56 
01.60 -  32:  52 + 0 =  56 
01.70 -  33:  51 + 0 =  56 
01.70 -  34:  48 + 0 =  56 
01.80 -  35:  49 + 0 =  56 
01.80 -  36:  50 + 0 =  56 
01.90 -  37:  50 + 0 =  56 
01.90 -  38:  51 + 0 =  56 
02.00 -  39:  52 + 0 =  56 
02.00 -  40:  53 + 0 =  56 
02.10 -  41:  55 + 0 =  56 
02.10 -  42:  53 + 0 =  56 
02.20 -  43:  47 + 0 =  56 
02.20 -  44:  48 + 0 =  56 
02.30 -  45:  50 + 0 =  56 
02.30 -  46:  50 + 0 =  56 
02.40 -  47:  47 + 0 =  56 
02.40 -  48:  45 + 0 =  56 
02.50 -  49:  47 + 0 =  56 
02.50 -  50:  49 + 0 =  56 
02.60 -  51:  51 + 0 =  56 
02.60 -  52:  50 + 0 =  56 
02.70 -  53:  52 + 0 =  56 
02.70 -  54:  51 + 0 =  56 
02.80 -  55:  56 + 0 =  56 
02.80 -  56:  58 + 0 =  58 
02.90 -  57:  50 + 0 =  56 
02.90 -  58:  48 + 0 =  56 
03.00 -  59:  52 + 0 =  56 
03.00 -  60:  50 + 0 =  56 
03.10 -  61:  52 + 0 =  56 
03.10 -  62:  50 + 0 =  56 
03.21 -  63:  52 + 0 =  56 
03.31 -  64:  57 + 0 =  57 
03.31 -  65:  49 + 0 =  56 
03.41 -  66:  55 + 0 =  56 
03.41 -  67:  50 + 0 =  56 
03.51 -  68:  48 + 0 =  56 
03.51 -  69:  50 + 0 =  56 
03.61 -  70:  48 + 0 =  56 
03.61 -  71:  48 + 0 =  56 
03.71 -  72:  47 + 0 =  56 
03.71 -  73:  46 + 0 =  56 
03.71 -  74:  47 + 0 =  56 
03.81 -  75:  49 + 0 =  56 
03.81 -  76:  48 + 0 =  56 
03.91 -  77:  52 + 0 =  56 
03.91 -  78:  54 + 0 =  56 
04.01 -  79:  52 + 0 =  56 
04.11 -  80:  57 + 0 =  57 
04.11 -  81:  50 + 0 =  56 
04.21 -  82:  52 + 0 =  56 
04.21 -  83:  54 + 0 =  56 
04.31 -  84:  55 + 0 =  56 
04.31 -  85:  56 + 0 =  56 
04.41 -  86:  56 + 0 =  56 
04.41 -  87:  55 + 0 =  56 
04.51 -  88:  57 + 0 =  57 
04.51 -  89:  51 + 0 =  56 
04.61 -  90:  52 + 0 =  56 
04.61 -  91:  53 + 0 =  56 
04.71 -  92:  54 + 0 =  56 
04.81 -  93:  55 + 0 =  56 
04.81 -  94:  57 + 0 =  57 
04.91 -  95:  57 + 0 =  57 
04.91 -  96:  56 + 0 =  56 
05.01 -  97:  59 + 0 =  59 
05.01 -  98:  60 + 0 =  60 
05.11 -  99:  57 + 0 =  57 
05.21 - 100:  56 + 0 =  56 
05.21 - 101:  62 + 0 =  62 
05.31 - 102:  63 + 0 =  63 
05.31 - 103:  64 + 0 =  64 
05.41 - 104:  60 + 0 =  60 
05.51 - 105:  62 + 0 =  62 
05.51 - 106:  65 + 0 =  65 
05.61 - 107:  70 + 0 =  70 
05.71 - 108:  79 + 0 =  79 
05.81 - 109:  87 + 0 =  87 
05.91 - 110:  92 + 0 =  92 
06.01 - 111: 110 + 0 = 110 
06.11 - 112: 130 + 0 = 130 
06.31 - 113: 167 + 0 = 167 
06.51 - 114: 215 + 0 = 215 
06.81 - 115: 291 + 0 = 252 
07.11 - 116: 335 + 0 = 252 
07.51 - 117: 400 + 0 = 252 
07.91 - 118: 438 + 0 = 252 
08.41 - 119: 461 + 0 = 252 
08.91 - 120: 490 + 0 = 252 
09.41 - 121: 502 + 0 = 252 
09.91 - 122: 471 + 0 = 252 
10.31 - 123: 422 + 0 = 252 
10.71 - 124: 416 + 0 = 252 
11.11 - 125: 409 + 0 = 252 
11.51 - 126: 387 + 0 = 252 
11.91 - 127: 356 + 0 = 252 
12.21 - 128: 327 + 0 = 252 
12.51 - 129: 311 + 0 = 252 
12.81 - 130: 288 + 0 = 252 
13.11 - 131: 286 + 0 = 252 
13.31 - 132: 277 + 0 = 252 
13.61 - 133: 280 + 0 = 252 
13.91 - 134: 252 + 0 = 252 
14.11 - 135: 250 + 0 = 250 
14.41 - 136: 227 + 0 = 227 
14.61 - 137: 235 + 0 = 235 
14.81 - 138: 224 + 0 = 224 
15.01 - 139: 217 + 0 = 217 
15.21 - 140: 209 + 0 = 209 
15.51 - 141: 210 + 0 = 210 
15.71 - 142: 205 + 0 = 205 
15.91 - 143: 195 + 0 = 195 
16.01 - 144: 186 + 0 = 186 
16.21 - 145: 181 + 0 = 181 
16.41 - 146: 186 + 0 = 186 
16.61 - 147: 181 + 0 = 181 
16.81 - 148: 182 + 0 = 182 
16.91 - 149: 180 + 0 = 180 
17.11 - 150: 174 + 0 = 174 
17.31 - 151: 180 + 0 = 180 
17.51 - 152: 160 + 0 = 160 
17.61 - 153: 169 + 0 = 169 
17.81 - 154: 155 + 0 = 155 
17.91 - 155: 162 + 0 = 162 
18.11 - 156: 154 + 0 = 154 
18.31 - 157: 164 + 0 = 164 
18.41 - 158: 158 + 0 = 158 
18.61 - 159: 155 + 0 = 155 
18.71 - 160: 151 + 0 = 151 
18.91 - 161: 156 + 0 = 156 
19.01 - 162: 153 + 0 = 153 
19.21 - 163: 144 + 0 = 144 
19.31 - 164: 147 + 0 = 147 
19.51 - 165: 148 + 0 = 148 
19.61 - 166: 146 + 0 = 146 
19.81 - 167: 157 + 0 = 157 
19.91 - 168: 139 + 0 = 139 
20.11 - 169: 143 + 0 = 143 
20.21 - 170: 149 + 0 = 149 
20.41 - 171: 145 + 0 = 145 
20.51 - 172: 144 + 0 = 144 
20.61 - 173: 147 + 0 = 147 
20.81 - 174: 141 + 0 = 141 
20.91 - 175: 143 + 0 = 143 
21.11 - 176: 143 + 0 = 143 
21.21 - 177: 144 + 0 = 144 
21.41 - 178: 140 + 0 = 140 
21.51 - 179: 138 + 0 = 138 
21.61 - 180: 143 + 0 = 143 
21.81 - 181: 138 + 0 = 138 
21.91 - 182: 138 + 0 = 138 
22.11 - 183: 138 + 0 = 138 
22.21 - 184: 138 + 0 = 138 
22.31 - 185: 132 + 0 = 132 
22.51 - 186: 139 + 0 = 139 
22.61 - 187: 138 + 0 = 138 
22.71 - 188: 142 + 0 = 142 
22.91 - 189: 134 + 0 = 134 
23.01 - 190: 135 + 0 = 135 
23.11 - 191: 131 + 0 = 131 
23.31 - 192: 138 + 0 = 138 
23.41 - 193: 136 + 0 = 136 
23.51 - 194: 129 + 0 = 129 
23.71 - 195: 136 + 0 = 136 
23.81 - 196: 128 + 0 = 128 
23.91 - 197: 138 + 0 = 138 
24.11 - 198: 140 + 0 = 140 
24.21 - 199: 138 + 0 = 138 
24.41 - 200: 136 + 0 = 136 
24.51 - 201: 138 + 0 = 138 
24.51 - Avg: 121 - Max: 502

time - flow meter count : state duration + user compensation = motor output
Output profile = flow meter state duration w/lower limit (preinfusion) = 56 and upper limit = 252.

#253: Post by **Jacob** » January 27th, 2012, 11:20 am

From very early in the thread people were talking about the best way to configure a pressure profiling system - just to pick a few:

shadowfax wrote:Greg has also speculated about an even more interesting setup, which would vary pressure based on flow through the group--this would allow you to actually simulate the action of a spring lever, where the pressure declines only as there is flow out of the group, rather than as time progresses. This would get you a system that reacted to the shot's flow resistance, which might be more interesting than simple pressure x time-based control.

For my part, I'm waiting for Tom to try his second-tier solution and see if that's adequate before I think about doubling my investment with a PID and transducer.

another_jim wrote:When these experiments started, I wondered if a good benchmark for a pressure profile was constant flow. What I mean is that the espresso starts with a drip, then over the course of the shot the flow gets stronger, and by the end it can gush. I don't mean cranking up the pressure to get high flow at the beginning, but dropping the pressure in such a manner that the flow stays constant over the final 2/3rd or so of the shot.

I have no justification for doing this other than it would turn out to be simple and elegant if it were true.

gscace wrote:It's one idea, and one way of varying grind, while maintaining a certain volume of shot, although not necessarily constant extraction ratio. I recently built a system for Phil and Sebastian Coffee Company in Calgary, and they are trying all sorts of things. their thinking is that fines migration gets locked down when the cake gets saturated, so if you gradually saturate,then increase pressure relatively slowly, you'll use a finer grind than if you don't pre-infuse, and ramp the pressure quickly. So you'll get very different extractions. I'm interested, of course, and I'm glad some other folks are doing all of this exploration, since my time is pretty limited. Seems to me that the Extract Mojo system could be of great use in this.

-Greg

CRCasey wrote:I had a couple of thoughts when reading this thread.

First off, you already have a nice digital flow meter built into you machine. Any automatic will have a Gicar flow meter with a nice digital output back to your controller board. You should be able to tap into this line (with a opto-isolator for extra safety) and feed it our to your PIC or what ever uC you decide to use.

Secondly a basic RC filter placed on any PWM output pin will be able to produce the 0-5V signal you require for the pump controller board.

With these two simple parts you should be able to test Jim's constant flow theory with just a dozen or so lines of code.

shadowfax wrote:I'd be very impressed if an espresso machine flow meter provided remotely fast enough feedback to facilitate real-time calculation of flow rate. I think at espresso flow that a flowmeter pulses at most <10 times per second (is that right?). Even if it were a bit more than that, the latency on measuring average flowrate will be quite high. That will probably put a cramp on the accuracy of any control system. But I perhaps there are better flowmeters or even self-contained flow-rate meters out there.

... Am I crazy to think it won't work?

Did any of you early adopters got beyound a manually controlled system?
What kind of configuration did you end up with? Or in case you didn't; why not?
Any plans for the future of your system?

January 27th, 2012, 11:57 am

I'm still stuck on manual. I've told myself I should learn to program an Arduino, etc., but I still haven't gotten around to it. I spent a lot of time recently shooting the breeze with Scott from La Marzocco, and he discussed a tremendous amount about the development of the Strada EP. That's actually made me lose a lot of interest in a DIY solution. From what I understand, getting the control right is a very tweaky thing. Especially trying to get the fastest stabilization during preinfusion as the feed tube and space above the puck fill with water.

I did learn that they like a profile that looks like this: /\ -i.e. a linear pressure rise to a peak and then a linear decline from there. That is, kinda-sorta like a lever profile, but actually very, very different. They say that modulating the total time and the peak pressure give you great ability to tweak a shot profile based on the coffee you're using.

So, I don't know where I'm at with all this. I have a pretty good time profiling by hand for the most part, but I know I suffer a large degree of repeatability there. I'm leery of getting a simple setup, like a straight-up PID that you have to program a ramp-soak function by hand any time you want to make a change-I'd really like something that's a little easier to tweak on a per-shot basis AND offers repeatability once dialed in.

I've vaguely considered getting a Strada EP, but... whew, sticker shock to the tune of >$10,000, even with a deep discount! I'm thinking, does my son really need to go to college?

#255: Post by **dsc** » January 27th, 2012, 12:20 pm

Before I dropped the project I've had man / auto control with various pressure profiles. The operator was able to 'record' his manual profile and the replay it with the Load function. The record-replay thing was working perfectly, but the PID controller I've implemented in my PIC uC wasn't tweaked properly (it was a matter of getting the parameters right). Unfortunately I couldn't be bothered to finish it and anyone who tried knows that coding is basic ASM, especially a PID algorithm, is not the best thing. There was the option of going full blown C, but that would mean re-writing the whole code...On a positive note, because it was ASM, it was crazy fast.

Regards,
dsc.

#256: Post by **Jacob** » January 29th, 2012, 4:35 am

Thanks

Tom your system were the perfect companion to a manual setup

shadowfax wrote:I've told myself I should learn to program an Arduino, etc., but I still haven't gotten around to it.

I'm having a blast with Arduino and think I have come a long way during the first 6 or so weeks.
Just this past week:
Last Friday I've installed a real time clock with backup battery (and some extra memory that I'm now using for storing user definable variables) and I then decided to use the rest of the weekend to log some data with the old pump.

By Sunday I were fed up having to have the computer in kitchen and installed a SD-card for the logs.
By Tuesday I were fed up having to transport the SD-card back and forth and installed an Ethernet device and a now I get my logs via a web browser.
Using another Arduino I have now made a simulator that simulates the output from the GS3 and I have moved the system from the kitchen to the study.

shadowfax wrote:... Am I crazy to think it won't work?

I think it would be crazy not to give it a try

#257: Post by **Jacob** » February 5th, 2012, 5:25 pm

I'm using the standard bypass valve!

GS/3-AP (Auto Profile) - first auto profile shot

Now the eternal search for the magic conversion algorithm can begin

#258: Post by **Jacob** » February 14th, 2012, 3:45 pm

The auto approach actually works!
But unfortunately for everyone else this test setup is placed in the private kitchen of a danish no-name amateur

#259: Post by **Gerry** » February 14th, 2012, 9:47 pm

Yes, that is unfortunate, Jacob, so you will have to keep us all in the loop. Biggest question: Have you confirmed that shots taste better with pressure profiles other than what would normally happen with a gicleur-limited E-61 or equivalent?

#260: Post by **dsc** » February 15th, 2012, 4:41 am

Awesome Jacob! Been there myself so I know how great it is to see it work correctly:) even if the shots taste similar there's loads of room for experiments and of course the grand satisfaction of doing it all on your own:)

Regards,
dsc.