Introduction: Table for Electronic Dreams
Step 1: Gather Parts!
You will need:
PARTS LIST
15 circuit boards
15 LM324 quad op amp
15 14-pin sockets
60 white LEDs
60 induction coils*
* Currently I am using coils from Digikey part number M10013-ND. The inductance is 4.7mH. They do not look like the ones pictured in this instructable.
60 10 ohm resistors
60 10M ohm resistors
60 1K ohm resistors
30 100K ohm resistors
15 10 μF capacitors
60 0.1 μF capacitors
You could change these numbers if you want to make a smaller table. There will be 1 quad op amp, 4 LEDs and 4 induction coils for each board.
For the table:
1/4 inch translucent white acrylic 33" x 21"
1/4 inch clear acrylic 33" x 21"
aluminum u-channel
For op amps I am using a quad op amp LM324, but you can use any op amp chip.
Step 2: Plan Circuit
Follow the schematic and connect the components properly.
You can do this on a perfboard or a printed circuit board if you want to be fancier. I am selling printed circuit boards , please see my website for details on ordering boards.
Essentially the coil picks up a voltage, which is amplified by the op amp, which drives an LED.
I have placed the coil next to the LED so there is more of a one-to-one correspondence between detected field strength and LED brightness.
See a legible version of the circuit diagram here: http://andydoro.com/table/images/circuit.gif
Step 3: Assemble Circuit
Assemble components onto a printed circuit board.
You can also use perf board.
The board should run on between 3 to 5 V DC current. Use a voltage regulator (7805 or 3940) in order to get a steady voltage.
Step 4: Test the Board
Oh look, it's working!
Step 5: Repeat!
You can keep making circuit boards!
Step 6: Mount Circuit Boards
I mounted the circuit boards to some transparent acrylic.
I placed the boards so that the LEDs are in a 3 inch pitch grid.
You can then connect the powers and grounds of each of the boards together with some wire.
Step 7: Test the Circuits
You can test the circuits' responsiveness to electronic devices.
I used a cellphone, but it works best if the cellphone is in use. You can try calling a friend or checking your voicemail.
Step 8: Build Table
You can install these circuits into an existing table, or build your own.
Actually, it doesn't have to be a table at all...
Step 9: Finishing Touch
Now you can place a sheet of translucent white acrylic above the layer of circuits to diffuse the light from the LEDs.
I used small white vinyl bumpers for the acrylic to sits on top of.
Step 10: Done!
For more information and a video, please see http://andydoro.com/table/
Thanks!

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122 Comments
9 years ago on Introduction
How do I rectify the problem of LEDS always on ???
9 years ago
hi....i'm new here...how can i get the schematic of this cool stuff (gandini43@hotmail.com)
9 years ago
hi....i'm new here...how can i get the schematic of this cool stuff
9 years ago on Introduction
you should include a pin by pin, i have tried nearly every possible configuration and none seem to work
10 years ago on Introduction
Hi, What is the total power supply used for the entire circuit once all the seperate circuits are connected?
14 years ago on Introduction
My unit works but no longer works when I use a wi-fi or bluetooth. What do you use the coil? 470UH or 1000UH?
Sorry for my English.
Reply 11 years ago on Introduction
How did you rectify your problem.... ( LEDs always on) ???
14 years ago on Introduction
hi i plan on buying the induction coils from http://www.digikey.ca/ could anyone paste the part # or link as to which one i should order for this project.
thanks
Reply 14 years ago on Introduction
Hi snoopdog416 My son and I have been experimenting with the circuit and we were struggling with the best coils to use. I can advise now that in our experience it dosent appear to be a big issue what coils you use. We have managed to get the circuit to work using a wide range of coils and even got it working with a small section of straight wire in place of the coil !! Please note our test circuit was set up on a bread board using a number of small connecting wires. The small connecting wires may have had an impact on the sensativity of the coil. If I was you I would test your circuit with a cheap coil or section of wire before I purchased 60 new coils. Cheers D McC
Reply 13 years ago on Introduction
Hello DMcC,
Thanks for pointing out regarding the 3-cm wire in lieu of 4.7mH inductance coil,
however, can you please share the snap /picture of your bread board setup for this,
as I want to make this, and i am not that good into electronics, and i see this is dual sided PCB.
so, i would like to test it on bread-board first.
Thanks in advance.
Reply 13 years ago on Introduction
Hi thexplanet
Unfortunately I have moved home since I played around with this circuit (back in June 2009) and dont have ready access to the breadboard.
I would recommend that you set up the circuit a replace the coil with a short section of wire and see if that works for you. My son and I discovered that a short section of wire worked quite well as a replacement for the coil.
good luch
D McC
Reply 13 years ago on Introduction
Thanks DMcC,
I did the entire re-design of this ckt, and got it working for an Inductor with 4.7uH
can you explain which mode is the LM324N is working in? or why is it only LM324N? being used.
Is it RF / Microwave or EM?
Thanks
Reply 11 years ago on Introduction
Can you please post the redesign of the circuit ???
Reply 14 years ago on Introduction
Hi DMcC Thanks for you input, I really have no experience using induction coils. I would appreciate it if you could perhaps paste a couple links from digikey.ca as to what coils would be appropriate for this project and then i could order a select few and experiment with them before i purchase a large amount. There are so many types on digikey that its overwhelming! thanks
Reply 14 years ago on Introduction
Hi snoopdog I have had success with the following coils from a local company
http://www.altronics.com.au/index.asp?area=item&id=L8260
http://www.altronics.com.au/index.asp?area=item&id=L6230
But as mentioned in my last post I don't believe it really matters what coil you use as we also had success with using 3 cm of wire in place of the coil.
If you set up a test circuit on a bread board you will see for yourself that the coil rating is not important.
All the best
D McC
11 years ago on Introduction
The LED's are always on..... When I bring a cell phone in, LEDs are flickering.... Can anyone suggest what should I do???
12 years ago on Introduction
the minimun order for the induction coils from Digikey is 1000 which is too high and too expensive. Does anyone know where i can get the induction coils needed?
12 years ago on Introduction
Amazing. So, have you found out whether or not cell phones dream of electric sheep?
13 years ago on Introduction
hi....i'm new here...how can i get the schematic of this cool stuff (or maybe anyone selling the pcb completely with all componens (how much it cost?)
all email are welcome sekutu@hotmail.com / tomz_eternity@yahaoo.com
Reply 12 years ago on Introduction
Hi. The PCBs and components are available as kits from my website: http://andydoro.com/table/order.html