Hello,
I want to build a shot dispenser Maschine like that:
Which Sensors I could use to detect if there is a glass on a specific Spot or not? I dont want to use visible Buttons which will be pressed by the glass. I thought about something like a capacitive Touch sensor hidden below a thin plate. But I dont know if that could work.
Thank you for your Suggestions!
I think a shot glass would reflect some light.
If so, a white bright LED shining up with a photo sensor beside might work.
Normally, the LED light goes straight up.
A glass would reflect this light back down to the sensor.
2nd
A sensitive micro switch under a water proof floor would close by adding the weight of the shot glass.
Thank you for the Quick reply!
These are good ideas. But with the Micro switch... How would I build it waterproof but elastic? Since the surface where the glass is placed has to move a bit up and down.
Have you there any idea? 
Actually you could bend the stainless steel arm so it protrudes slightly higher than the surface the glass sits on.
Maybe just a 1mm hole for the wire to go thru.
Flow sensor:
Hmm that would be possible but I dont want to See something above the surface...
With this I can not detect a glass, can I?
Then use the LED/photo sensor.
I think so... Would you build it then just under the White led or how?
Use an IR sensor so ambient light doesn’t give false detection.
Is that a device which is a combination of led and sensor?
Oh that's nice I never saw one like that thank you very much
It is dispenses the amount of liquid you command.
Ah okay thats nice thank you for that
Would it be possible to hide such a sensor below a opal glas for example?
Use a scale to find the right glass.
What exactly do you mean by that? How can I be sure that my light will go through the glass?
I don't want to distract the conversation from the optical sensors, but if you are not sure if your glasses will reflect light an ultrasonic sensor (such as the HC-SR04) can also do the job. The disadvantage is that they are much larger than the IR sensors, and your glass would have to be wider than the sensor itself.
If you bend the micro switch arm you can have a short piece sticking up where glass goes , unnoticeable ! The weight of the glass then trips the switch .
Problem is , unless you drink a lot you have to switch the system on and off which takes longer than a normal optic dispenser .
Old shot lying in the pump may well take a funny smell from the rubber parts .
Maybe just me , but simple is good …
You need to guard against it going wrong too and emptying your alcohol all over the floor when you are out .
