Maker Pro
Maker Pro

Beer Pong Table. Please help

nitram

Jun 25, 2012
9
Joined
Jun 25, 2012
Messages
9
I am currently in the design stages of a custom beer pong table. I have planned for the area under the cups to light up when you have a cup (with liquid) on top of the spot and to turn off when there is no cup on it.

However Im not exactly sure how to go about this. I dont know what kind of sensor to use. I also dont know if it would be better to use lacquer to protect the electronics for drunken players or a combo of plexi-glass and lacquer.

Im wanting to use clear Solo cups so they glow. Also naturally leds are what I want to use as lights.

I didnt really find anything within the forms and if there is feel free to post a link. PLEASE help and thanks in advance for any and all advice on this :)
 
Last edited:

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
Joined
Jan 21, 2010
Messages
25,510
You could detect the weight of the cup, or you could have an inductor under the cup position and a circuit that senses a change of inductance (perhaps by frequency of oscillation) when something is on top of it.

Maybe you could do it optically, but it might be difficult to detect an empty/full glass. If there is something above the glasses then perhaps you could look at transmission of light through the glass and liquid to determine if there was any liquid in the glass.

Most of these would require some sort of calibration and likely a known (and fixed) type of cup.

I have a colleague who once played with the detection of clear oil on a clear tube by measuring the difference in refraction of light as it passed through the tube. you might be able to do the same, it may even change the reflective characteristics of the bottom of the glass.
 

CocaCola

Apr 7, 2012
3,635
Joined
Apr 7, 2012
Messages
3,635
Clear cups pose a challenge, that will require a lot of filtering/calibration to detect properly if going optical... Especially with a clear liquid...

If you modified the cups bottom a little you car really simplify things, the addition of something as simple as a tracing paper 'coaster' attached to the bottom of the cup will make optical detection a whole lot easier and still allow light to illuminated by from underneath the table... Detection can then just be a photocell, once calibrated to the ambient light when the cup is placed on top you will have a measurable change... But, at the same time when you illuminate the cup this value will change again, so you would need to take that into consideration...

Ambient light level = off
Covered hole with translucent cup = on
Reflected light due to LED illumination (distinguished value from ambient) = hold on
Ambient light level = off

The drawback to this is calibration, different ambient light levels as well as different liquids in the cup as well as a ball in the cup all change the value and need to be compensated for...

With a decent high output LED you might be able to use the traditional red/blue cups and still get decent illumination, this would also make calibration much easier...

I suspect the most reliable way might be to use capacitive proximity sensor though...

As for table top, I would suggest a single sheet of plexiglass (perspex) this allows for graphics to be painted on the table itself and then the plexiglass protects everything when placed on top...
 

nitram

Jun 25, 2012
9
Joined
Jun 25, 2012
Messages
9
Iv been thinking on this all day and Iv came to two different possibles which both of you have expressed, at least that's what Iv gotten out of it.

1) a pressure type switch
2) using light to trigger the lights. also im fine with switching to classic red cups the clear was just an idea.

Im not really sure what parts I would need in order to accomplish either of those or how to hook it up.

I'm sorry I not trying to be a pain or greedy I just don't really know anywhere else to turn for help. I dont have a teacher I could talk to and I'm the only one out of my friends who mess with anything like this and Im kinda new to a lot of this but im eager to learn. I really appreciate every bit of help yall provide.
 

poor mystic

Apr 8, 2011
1,074
Joined
Apr 8, 2011
Messages
1,074
:)
You could use a colour camera. My skilled-up friend assures me that image recognition freeware could do the rest in a trice.
(he didn't say it was easy to learn to use the freeware, but i bet you'd soon find help on a robotics forum)
 
Last edited:

SurfBum96818

Jun 29, 2012
1
Joined
Jun 29, 2012
Messages
1
I completely understand the desire to have the table sense the presence of a cup, however you have expressed that you are very unfamiliar with the processes involved in doing so. Might I suggest something that would greatly simplify things. It would facilitate the use of clear cups which by the way would look way better. Either at the center of the table or at each end have a simple on off switch set up mimicking the shape of the cup configuration. More than likely set it up so that with the first push it turns the light say in a blue color, second push green third push red etc etc until it goes off. 1
2 3
4 5 6
7 8 9 10
each number being a switch.
 

nitram

Jun 25, 2012
9
Joined
Jun 25, 2012
Messages
9
I completely understand the desire to have the table sense the presence of a cup, however you have expressed that you are very unfamiliar with the processes involved in doing so. Might I suggest something that would greatly simplify things. It would facilitate the use of clear cups which by the way would look way better. Either at the center of the table or at each end have a simple on off switch set up mimicking the shape of the cup configuration. More than likely set it up so that with the first push it turns the light say in a blue color, second push green third push red etc etc until it goes off. 1
2 3
4 5 6
7 8 9 10
each number being a switch.

I like your idea and yea im not exactly experienced with the whole pressure sensing procedure but I am extremely eager to learn move about electronics specificly small stuff like this. Im have trouble however finding a switch that is pressure activated, no pressure= off with pressure=on
 

CocaCola

Apr 7, 2012
3,635
Joined
Apr 7, 2012
Messages
3,635
Im have trouble however finding a switch that is pressure activated, no pressure= off with pressure=on

That would be a NO (normally open) momentary... This is how most momentary switches are configured, the pressure to activate varies drastically between switches though... I have come across so 'rice' sized ones that hardly take any pressure to activate, just a small pin like actuator sticking out a little bit... And there are other methods like those employed in resistive touch screens where it's simply two plates slightly spaced apart that when pushed make contact with each other...

May I suggest another novel idea, using magnetic reed switches in the table and putting a small neodymium magnet in the bottom of the cup to activate it when placed on top...
 

nitram

Jun 25, 2012
9
Joined
Jun 25, 2012
Messages
9
And there are other methods like those employed in resistive touch screens where it's simply two plates slightly spaced apart that when pushed make contact with each other...

I like this idea it sounds cheep and effective. this is how i am visualizing this let me know if its way off. i take say a clouded plastic puck, so the light disperses nicely, adhere a copper circle to it then put some kind sheet of foam, not sure what kind tho. then adhere a copper circle to a wooden shelf that's attached to underneath the table. the foam would act as a spring to keep the puck up and the two copper plates apart when there is no pressure, weight of glass, but compress easily when there is.

(power + )-----( leds )-----( plate ) ( plate )----( - power)

does that make sense or would that not work at all?

also would this reed switch work for your magnetic idea? link
 

Laplace

Apr 4, 2010
1,252
Joined
Apr 4, 2010
Messages
1,252
An alternative approach that may be worth experimenting with is a sensor based on the theremin, a musical instrument controlled by how close one's hand is to the sensing antennae which changes the oscillation frequency of several hundred kilohertz slightly as the hand changes the capacitance in the LC tank circuit. If you placed the sensor beneath the glass tabletop, would a glass of beer cause sufficient frequency shift to be detectable? You probably would not need to use the heterodyne circuit, just use a microcontroller as a frequency counter. Would beer spilled on the table top also be detectable? Is the permeability of beer sufficient to also change the inductance in the LC tank? If so, then the design of the sensing mechanism under the glass could take advantage of that fact. Furthermore, using a microcontroller would make it easy to trim for long-term drift. This idea may not be feasible but it would be interesting to find out. Inquiring minds want to know!
 

CocaCola

Apr 7, 2012
3,635
Joined
Apr 7, 2012
Messages
3,635
nitram at this point every idea would need some trial and error testing in the real world, and due to you lack of actual electronics knowledge I fear that most of the suggestions are over engineered to the point that the project will never actually move forward...

At this point I would start simple and get something working, if and when you decide to invest further you can 'upgrade' the existing design... I would probably skip all sensors at this point and just get the table up and running with lights for each cup, attached to real work on/off switches that you do manually... Once you have the table built and the lights working you can tinker with automated ideas...
 

nitram

Jun 25, 2012
9
Joined
Jun 25, 2012
Messages
9
CocaCola i appreciate the concern and understand it as well and i agree a lot are over my head, i hope to get to that point at some time where i understand the mechanics of microcontrollers and stuff like that but I dont have the opertunity at my current school to grow in those areas.

But I fell like your last suggestions I can accomplish. I'm the type of person where I get an idea stuck in my head and I will not be satisfied until the finish product is what is pictured, kind of a perfectionist.

That being said I'm curious if I was moving in the right direction with my last post in response to yours?
I like this idea it sounds cheep and effective. this is how i am visualizing this let me know if its way off. i take say a clouded plastic puck, so the light disperses nicely, adhere a copper circle to it then put some kind sheet of foam, not sure what kind tho. then adhere a copper circle to a wooden shelf that's attached to underneath the table. the foam would act as a spring to keep the puck up and the two copper plates apart when there is no pressure, weight of glass, but compress easily when there is.

(power + )-----( leds )-----( plate ) ( plate )----( - power)

does that make sense or would that not work at all?

also would this reed switch work for your magnetic idea? link

I'm looking for guidance and a point in the right direction if im going about things wrong. Im not however looking for someone to spell out step for step what I need to do because well honestly thats not a how i learn, i learn best with trial and error and hands on. If that makes sense.

I really really do appreciate your suggestions and ideas, Iv actually ordered LEDs and other necessities so I can start trying out different designs to see what will work best.

I hope you will continue to help and guide me and not discontinue your help on account that i'm a Newb at this. Thanks for all your ideas and hopefully Ill be able to start posting pictures and questions about real prototypes within a few days.
 
Top