# Gaggia Classic - automatic shot timer



## MrShades (Jul 29, 2009)

My current project is to have the Classic automatically time shots - 27s etc

I've got a working setup now - that can do any time with 0.1s resolution, and once set (to 27s for example) can be forgotten about - and the Classic used in the normal fashion with the brew switch... except it magically turns off at the predetermined time.

Here's a couple of quick videos (must fix the lights in my conservatory - it's pretty dark):

Ignore the espresso quality (I just took 18g of grinds that were ground by the K10 for my Duetto - so almost choked the Classic) - here's a 27s shot:






...and here's a 5 sec back flush (or two):






I'm not divulging how the magic happens just yet... needs a bit more work. ;-)


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## Krax (Oct 26, 2014)

Good to see it working, another worthwhile mod for the Classic, please let me know when you have it finalised


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## froggystyle (Oct 30, 2013)

Liking that. What would be cool is to have a set of scales talking to a raspberry unit, set the weight and have it turn off when set weight reached!


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## MrShades (Jul 29, 2009)

Errrr - yeah.... this method is cheap (like £20 cheap) and cheerful!

Doing it with volumetric sensors might be a bit more feasible - but due to the classic plumbing it wouldn't be quick or easy (or cheap).


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## froggystyle (Oct 30, 2013)

Yeah I guess would take it outside of the realms of reality for the classic, but if you could knock one up that could be wired into any machine.....


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## Finley (Oct 19, 2014)

Superb, would be really interested in this once you have it finalised!


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## majnu (Jan 31, 2014)

Looking good. Are there any machines out there that stop the brew by user defined weight of coffee output? Also do you pull your shots at 93 degrees celcius mrshades? I've Not been happy with the taste of my espressos lately and I found lowering it helped a fair bit with the beans from Rave (They are all dark medium roasts )


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## MrShades (Jul 29, 2009)

93c- yes... But that equates to 101c boiler temp with the 8c offset that I have set


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## Mrboots2u (May 10, 2013)

A gravimetric system that is accurate is all kinds I'd complicated ....ask la marzocco and ns.....requires the scale to understand current flow rate to be able to shut of the pump for the right weight......fear it would cost alot more than the classic is worth to achieve


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## MrShades (Jul 29, 2009)

Yes - I'm with bootsy. Returns wouldn't be worth the investment in time money and effort required.


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## rob177palmer (Feb 14, 2017)

@MrShades - the vids have disappeared from this thread - do you have them anywhere please? I am planning this mod and researching how others have done it, and particularly which timer relays have been used.

edit - ignore me- have now found your other thread with the photos and videos still live! Thanks ?


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## MrShades (Jul 29, 2009)

rob177palmer said:


> @MrShades - the vids have disappeared from this thread - do you have them anywhere please? I am planning this mod and researching how others have done it, and particularly which timer relays have been used.


I'll have a look - the videos should still be there. Vimeo seems to have deleted them.... so will find them and upload them on YouTube instead.

I do have all the components to replicate what I did (I think I've got enough controllers and sensors and tubing etc for about 5 sets). So I can potentially help with parts if you're interested.


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## rob177palmer (Feb 14, 2017)

MrShades said:


> I'll have a look - the videos should still be there.
> 
> I do have all the components to replicate what I did (I think I've got enough controllers and sensors and tubing etc for about 5 sets). So I can potentially help with parts if you're interested.


Given the simplicity of fitting the PID you supplied, that could be a great option!

I started off thinking of a simple brew-switch controlled stopwatch to time how long each shots takes, but this solution could be better - fixing the time for the pour will force me to work harder on grind and tamp to hit the magic 30s.

Did you ever sort a suitable box??


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## MrShades (Jul 29, 2009)

rob177palmer said:


> Given the simplicity of fitting the PID you supplied, that could be a great option!
> 
> I started off thinking of a simple brew-switch controlled stopwatch to time how long each shots takes, but this solution could be better - fixing the time for the pour will force me to work harder on grind and tamp to hit the magic 30s.
> 
> Did you ever sort a suitable box??


Ah - yes - this is just the timer isn't it.... I thought it was the volumetric mod.... which I've got all the parts for.

The controller that I use can (I think) be used for either the volumetric mod (counting pulses from a flow sensor) or the shot timer (counting seconds). It's 1/16DIN so fits in my regular PID box.

Volumetric mod is more fun ;-)


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## rob177palmer (Feb 14, 2017)

MrShades said:


> Ah - yes - this is just the timer isn't it.... I thought it was the volumetric mod.... which I've got all the parts for.
> 
> The controller that I use can (I think) be used for either the volumetric mod (counting pulses from a flow sensor) or the shot timer (counting seconds). It's 1/16DIN so fits in my regular PID box.
> 
> Volumetric mod is more fun ;-)


PM sent


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## Richard_severn (May 3, 2017)

If the auto shot timer is purchased at the same time as a PID is there any chance of it being a bit cheaper, I realise you can't be making much on these, and I'm i right in thinking if you use your slimline PID and this timer mod that they would both fit in the same size box/enclosure as your original PID.

If you don't want this out on the open forum please drop me a PM i really want a PID on my classic and if i could get shot timer at the same time it may make me pull the trigger on a purchase


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## nightslayer (May 29, 2016)

Just my two cents - a built in shot timer might be (more) helpful/useful (or make sure to build in a manual cut-off to the auto shot timer) because keeping shot timing constant yields more irregular shots than keeping yield by mass constant I think! I have a 30s cut off on my Auberins PID but I never actually use that because I weigh my output and manually cut flow off at a predetermined weight instead (usually about 27s for 37g out of 18.5 but it fluctuates!), and just use the 30s countdown timer as a helpful guide to know how far off from 30s I am! Might also be easier than constantly having to adjust the grind to get the same yield if you only make one shot a day and your beans are constantly degassing..


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## MrShades (Jul 29, 2009)

Richard_severn said:


> If the auto shot timer is purchased at the same time as a PID is there any chance of it being a bit cheaper, I realise you can't be making much on these, and I'm i right in thinking if you use your slimline PID and this timer mod that they would both fit in the same size box/enclosure as your original PID.
> 
> If you don't want this out on the open forum please drop me a PM i really want a PID on my classic and if i could get shot timer at the same time it may make me pull the trigger on a purchase


If anyone is interested in doing this...

The auto shot-timer is actually a really easy DIY mod - and I published all of the details on here: http://coffeeforums.co.uk/showthread.php?21171-Automatic-shot-timer-project

All you need is one of the timers and a few pieces of wire. The only issue (as I've mentioned a few times) is that this timer doesn't fit any box I could find (it may fit my current 1/16 DIN PID box - will have to try it) - but anyway, finding a good enclosure for it was tricky (and ended up costing more than the timer itself).

Whilst you can get electronic timers, the key advantage of this type of timer is that it can be set without power applied to it. The way the mod works, once power is applied to the timer it instantly starts counting the time and then kills power to the output (pump/solenoid) once the time limit is reached. The timer then remains live and powered up until you flick the brew switch off, and then when you turn the brew switch on again the cycle repeats. Hence an electronic timer would need to be set after a brew had completed to its set time limit (or during the timing I guess) - as it'll require power. Anyway - it seems much easier with a "push + or push -" timer.

and ( @nightslayer ) you always have a manual cut-off when using the shot-timer - that being the brew switch. You always start a pour with the brew switch, and the pour will stop either when the time limit is reached or when the brew switch is turned off. Hence setting the time limit to 99.9s would allow the timer to be used purely (effectively) as a shot timer, with it automating nothing (other than the start of the timer when you throw the brew switch) - OK, it would stop a pour after about 1.7 minutes ;-)

I've got parts for the volumetric mod on a Gaggia - but it's not perfect (as the counter has to be reset by pressing a button in between shots). If anyone wants to buy the parts and some simple instructions to have a play with volumetrics then let me know. (Further discussed here, again without vids: http://coffeeforums.co.uk/showthread.php?29922-Gaggia-Classic-with-volumetric-control )


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