Proximity Detection Cubes

Hey Guys!

I have a project i'm working on for my son who is 2 and I need a little help if you guys don't mind.

I have some acrylic cubes that I laser cut and etched a letter of the alphabet on each cube. For my first step in this project I would like to have them glow with an led when the blocks/cubes are close to each other. The general idea here is that the leds are off by default but as the cubes get closer together they start to glow and get brighter the closer they get.

The cubes are 1"x1"x1" OD and so space inside the cubes is limited and I was wondering if you guys had any ideas on how to implement this with as few components as possible.

Thanks
John

Hello there MrSeaton,

I have to say this is a very very good idea in itself. The kids should get a real lick out of that.

Add to that the ability to detect words and you've got quite an invention i would think. For example, if the blocks close to each other spell something like "cat" then they light up. Would be cool i think. I might want to play with them myself

How close do you want them to have to be? Can you actually get batteries inside them?

That's actually where this project is going. The final goal is to have the cubes be programmable (from a portable hand-held device) via IR or RF (not sure yet). We want to be able to pick or spell a word and progam the cubes with that word, then when he puts the first two letters together they light up green and if he puts a wrong letter in there or in the wrong order then the wrong cube will light up red. When he is done spelling the word, the cubes will flash randomly to signal he spelled it correctly.

Yeah, a button cell battery should fit in there.

I figure about 1" apart the leds should be dimly lit and then fully lit when they are touching each other. I figure he'll have fun watching them light up as they get closer and dimmer as they get pulled away from each other and they have a letter on all six sides so he can be learning his letters all at the same time.

I've been working on how all this is going work and I realized this is going to be a big project and I wanted to start somewhere and then build upon that which is why I'm stating out with just lighting them up when they get close to each other.

You could use a hall effect magnetic sensor in the right side of a cube, and the magnet in the left side. So bringing them together the left cube would sense the magnet and light up.

As for programming and decoding a "word" with them, well that's a whole world of difficulty harder.

For limited distance and directionality with coding capability, how about having each cube with an IR emitter and detector along with the LED ? Acrylic plastic should be fairly transparent to IR. Power could be one of those little LiPo cells.

The problem I see is that will be awfully power hungry. Using a very low duty cycle flash rate (e.g., 3%) for the IRED could cut that energy need considerably.

John

Edit: I just measured the guts from one of those cheap, indoor IR remote helicopters. Including battery, the IR emitter, receiver, and blinking LED will fit easily inside a 1" cube.

Just for my information, is your laser a commercial unit or hobbyist? I happen to be looking for a hobbyist laser cutter (<<$4,000) at the moment. I know this OT, and if you are amenable , maybe PM would be the best way to discuss what you have. John

Mr RB said:

You could use a hall effect magnetic sensor in the right side of a cube, and the magnet in the left side. So bringing them together the left cube would sense the magnet and light up.

As for programming and decoding a "word" with them, well that's a whole world of difficulty harder.

Click to expand...

Yeah that would work i guess... I was hoping to make them not so much orientation specific but more proximity based. As far as the end goal project goes, I have the logisitcs figured out on how they are going to keep up with the word that is being spelled, it's just the eletronics that is taking me longer to get my head wrapped around.

jpanhalt said:

Just for my information, is your laser a commercial unit or hobbyist? I happen to be looking for a hobbyist laser cutter (<<$4,000) at the moment. I know this OT, and if you are amenable , maybe PM would be the best way to discuss what you have. John

Click to expand...

The laser cutter I have access to is a small 40watt unit that can only cut 11"X10" max.

hi,
I expect the Cubes would be assembled in a line on some sort of flat surface, in order to form a word.?

If that is the case, I would consider using a suitable base that contains the control and power supply.

The base would/could be marked the same way as a chess board, where the squares are the same size as the cubes.

The Base electronics would detect the presence of a cube and would light an led located in the centre of a base square, the LED would light up a semi-transparent cube placed over the LED.

E.

Here is a cute little IC that would do it:

https://pdf1.alldatasheet.com/datasheet-pdf/view/42903/SHARP/IS471F.html

The problems I see might be that the plastic may be pretty reflective so it might take a couple of holes to keep it from reflecting withing the cube.

Only one surface is active.

You would need some connetion to the outside world to recharge the battery.

Power is fairly low due to pulse operation - but....

ericgibbs said:

hi,
I expect the Cubes would be assembled in a line on some sort of flat surface, in order to form a word.?

If that is the case, I would consider using a suitable base that contains the control and power supply.

The base would/could be marked the same way as a chess board, where the squares are the same size as the cubes.

The Base electronics would detect the presence of a cube and would light an led located in the centre of a base square, the LED would light up a semi-transparent cube placed over the LED.

E.

Click to expand...

That's not a bad idea. That would definately help with the whole battery problem as the base could be the power source too.

I had been thinking along the same lines as EricGibbs.

I also thought that the power for the LED in the cube could be transferred from the base board to the cube by inductive coupling.

A small coil under each position in the base board, and a corresponding coil in the appropriate face of the cube.
If the coil in the base is energised at (say) 20 or 30kHz, there will be enough energy transferred to light the LED and drive a PIC which can be used to give the cube its "identity".

It should be possible to modulate the current taken by the cube to allow it to pass its identity to the base board.
Then in the base board, measure the current drain and have the base controller determine if the correct cube is in position.

How old did you say your boy was?
2 years old?
This would make a great 18th birthday present for him when it is finished!!

JimB

Yeah, I've spent all my available time since friday researching wireless inductive power transfer and trying to build one but so far I've been able to build the oscillator and that's about it.

Yeah, he'll be 3 in februrary.

Thanks for the idea for modulating the current, I wasn't sure how I was going to accomplish the communication of the cubes.

At the rate this is going it will be an 18th birthday present lol