Help with design for project

So Im working on designing a new island for my kitchen while im stuck deployed. Im incorporating my kegerator into it and also a drink dispenser. The thing im not entirely sure how to tackle is the detection of the size of the glass. The basic idea is the user can put a glass on a platform and then choose from a list of possible drinks.

The problem im trying to figure out is how to figure out the size of the glass so that it is idiot proof and they cant pick a drink that will overflow the glass.

Here are my current brainstorming ideas:

1. By weight with a range of acceptable weight for the glass, the problem with this one is different glass materials

2. IR sensors to measure the height and diameter and approximate the size, already going to use a IR sensor to detect the top rim to position the glass below the dispenser

3. Glass selection in the UI, this is a simple version but would allow a drunken guest to choose the wrong size and cause an overflow

Any Ideas for a drunk proof solution?

RFID tags attached to the bottom of each glass? OK, just joking...

How do soft drink dispensers work at fast food places? I believe the technology in use has changed now but it seems like at one point they just put a cup under the faucet and it would fill to the proper size each time.

Maybe someone with some McExperience can chime in...

Those where set sizes on the cups. My problem comes from my random assortment of glasses, plus the different kinds of glasses, plus the occasional part where different plastic cups will be used

I saw a soda dispenser that was able to tell when the glass was overflowing. It was the type where you had to push the glass up against a lever/switch. Once the foam just start to over flow, it would touch some metal pick-ups on the lever and signal the soda machine to cut the flow to that dispenser.

Pretty difficult task with unknown glass shapes, weights and volumes. The amount of carbonation and foam produced during the pour will add another variable which I think would be difficult to account for via any type of sensor.

As far as making it drunk proof, I think one's inability to pour a drink is your body's own sensor saying you're done for the night.

One of these might be able to sense full liquid level, but would require top registration for the rim, since vessel sizes will vary. Reckon you could make a "rim-stop" and guide to line up your sensor.

http://www.stedham.com/Examplebinlevel.htm

Non-technical solution... ditch the random glassware, and buy a nice set of glassware all the same size... just decide on a size, e.g. 12 oz., 500ml, etc.

Do that, and you can set the dispenser at that volume and hit it every time.

I know some soda machines use ultrasound to measure the fluid height in the cup. It doesn't totally solve the problem since you still wouldn't know the maximum height of the glass, but measuring just glass height with an IR sensor is easier than measuring the total volume. Also not sure how well ultrasound will be with foam. Foam's not very dense, so it might not give much ultrasound signal.

I bought an ultrasonic sensor pretty cheaply (~$10) that I've been wanting to use to sense the water level in my Hot Liquor Tank. It transmits an ultrasound pulse, measures return time, and gives a range reading in feet or meters or something. They're used on robots to range an object in its path. I'm thinking if you mount this little thing at the right angle, so that it gives a range reading off the rim of the glass, or your hand (make sure it's at the top!), a microcontroller could use the range reading to calculate the size of the glass. You'd still have to restrict the range of glass sizes to within its detection zone. This is all kind of speculation since I haven't played with it to see what it will really do yet.

However, I don't know if you'd get the required accuracy to differentiate between glasses close in size - it might only be able to sense 'big' or 'small' ranges and to prevent overflow, may need to also sense the rising fluid level. The sensor might see one signature when you first place the glass, to register it, then read the sensor as the signal reflects off the rising fluid level, which you track, until it reaches a pre-set threshold.

I'd be glad to post the US sensor info if you'd like.

Have the guest 1st choose the drink and then hold the glass up against a stop and sense when the glass is in place and despense only while the glass is against the stop, then you can sense the top of the liquid somehow and stop when it is as near the top as you want. If the guest moves the glass before it is full, there is no mess like there would be if you poured a fixed amount based on the glass size.
The stop would be where the guest would have to hold the glass up against it with the bottom of the glass not touching anything.

It seems like you're trying to make a novel solution to something that really isn't a problem.... While it's nice to have some flare and zaz in your setup, why not just use a good ol' fashioned manual tap?

bdh said:

I know some soda machines use ultrasound to measure the fluid height in the cup. It doesn't totally solve the problem since you still wouldn't know the maximum height of the glass, but measuring just glass height with an IR sensor is easier than measuring the total volume. Also not sure how well ultrasound will be with foam. Foam's not very dense, so it might not give much ultrasound signal.

Click to expand...

I'd go with this idea or bar code etched in each glass. Plenty of threads here on etching glass. I'm sure you could get the IR to notice the liquid making it to the edge. Either that have a kid and train him to be trustworthy and not spill anything.

So you're building this into your kitchen island?

http://robofun.ro/create/the-social-drink-machine/

I would recommend using a scissor lift to raise it up from the center of the island when in use. ...and possibly a fog machine and lasers for extra effect.

@ryan_george cause its fun to make things and experiment, plus during a party when people start to have a few too many it makes it so that the drinks are still quality drinks.

@Dude Trying to not use a standard set of glasses and have it be able to handle any glass type (to an extent)

@jpalarchio yes doing something similar to that, although mine works different and will be able to hook up mixers as well. I think ive gotten my design down and will be nice.

You all are getting silly now.