LED Orb 2.0

[13579]

Hey guys, I just started making one of these.

I'm about 60-70% done, my design uses no sliprings. I was pondering about how to get around their use, when I got an idea I had to test. Turns out on the motors I use, the metal motor body/metal shaft are isolated from the terminals. So I simply soldered a wire to the shaft and attached the wire to the turning axis to power the motors on that axis, and supplied power to the motor body (Body is apparently conductive to the shaft). So far this method has been a complete success, and I suggest you all test your DC motors to see if the shaft is isolated from the power terminals.

I also use two motors to rotate each axis. I'm undecided if I'm going to power both motors, as I'm not sure if the RPMs will match correctly, but even if I do end up powering only 1 motor, the other will serve as the perfect counterbalance for it.

The wooden axis with the arch and the axis that was made by soldered wire are replaced by a model I drew up last night around midnight and 3d printed (I'm a senior in highschool, friends with the tech teacher, so I have full access to a dimension 3d printer) out of black ABS plastic.

I've really got to thank the OP, this came just in time. I've been stressed and looking for something to make my girlfriend for christmas, and as soon as I saw this I knew it had to be done. You really saved my ass.

Pictures coming soon, I'm on dialup internet so it'll be a while. So far I have the "arch" axis and the "soldered metal wire" axis completely attached, balanced and motor/wired up. Working on the axis that the LEDs mount on, and the body that will rotate the "arch" axis.

Thanks again for a great project, really came with perfect timing. If this one is successful, I'm probably going to make a few more for friends/technology teacher.

 

[13579]

Now I'm starting to get pissed off. I just wired up the 3 LEDs in parallel and tried giving them power. Red and green were fine, blue was not. If I disconnected blue and tried wiring it up the same way as red and green, it would work fine. But as soon as it was connected to red and green, nothing. So I started taking away the resistors. I was down to 47 ohms and red and green were bright, but blue still wasn't on. So I hooked them up directly to 9 volts, and blue finally lit up.....then they all promptly flashed and died.

What the hell happened? Why didn't blue light up until I directly applied 9 volts to all 3 LEDs?

I'm about to grabs some more and try to get closer stats on them. The voltage and brightness was different for the 3 that I was using (I was using resistance required for the lowest voltage led to test).

 

[Jimmymcjimthejim]

You need separate resistors for each LED, as each LED has a different voltage drop. So since the blue LED has a larger voltage drop than the red and the green, more current goes through the red and the green than the blue.
This project is definitely no task for the novice, but I wish you luck on the remainder of your endeavor.

 

[13579]

You need separate resistors for each LED, as each LED has a different voltage drop. So since the blue LED has a larger voltage drop than the red and the green, more current goes through the red and the green than the blue.
This project is definitely no task for the novice, but I wish you luck on the remainder of your endeavor.

Damn. Well, this is embarrassing. Now that I think about it, I guess I've never tried to run LEDs in parallel before...

I guess I'll just run them in series, and use the required resistance of the lowest voltage led (if all 3 leds were the same). So if anything, two of them will be under-ran. Any problems with this?

Anyhow, here's some pictures of what I have so far:

Just waiting on more LEDs. Might use 10mm if I can find them with acceptable specifications.

 

[Hardwired101]

First off Firemylaser amazing build here. Ive nearly finished a version similar to your original but hit a bit of a snag. Im using PWM to controll the motors but I have a bit of a problem with the circuit I chose to use. Found at DPRG: A Simple PWM Circuit Based on the 555 Timer.

I built my system using a common ground and differing positive leads so I tried to remove the Mosfet. One of the attached pics. The circuit works perfectly fine with a multimeter but fails when attached to a motor, guessing the 555 cant generate the correct current. So is there anything I can do to use the positive output pulse to create a positive pulse with the current that the motor needs?

 

[anselm]

So is there anything I can do to use the positive output pulse to create a positive pulse with the current that the motor needs?

Isn't that what transistors (like the MOSFET is one) are for? :thinking:

 

[HIMNL9]

First off Firemylaser amazing build here. Ive nearly finished a version similar to your original but hit a bit of a snag. Im using PWM to controll the motors but I have a bit of a problem with the circuit I chose to use. Found at DPRG: A Simple PWM Circuit Based on the 555 Timer.

I built my system using a common ground and differing positive leads so I tried to remove the Mosfet. One of the attached pics. The circuit works perfectly fine with a multimeter but fails when attached to a motor, guessing the 555 cant generate the correct current. So is there anything I can do to use the positive output pulse to create a positive pulse with the current that the motor needs?

You can't use the discharge output from the 555 IC for drive directly a motor ..... it's not a power output, it's just an open-collector pin for discharge the timing capacitor, and don't have the needed current too.

Use a NPN transistor or a mosfet as power stage ..... if you want to keep that circuit (that is basically my old PWM driver, but drawed incorrectly), and a simple transistor, disconnect the motor from the IC, connect the collector of the transistor on the motor, and the emitter to GND (the pin marked -V motor must be connected to the positive, too, not to the negative), then connect the base of the transistor where you had the motor connected before, through an 1Kohm resistor (left the 10 Kohm one connected to the IC pin, i mean, and from there go to the base of the transistor with a 1 Kohm resistor) ..... be sure that the transistor can hold the current needed from the motor, too, and if needed, heatsink it.

Also, remember that motors generates spikes and disturbs ..... connect a capacitor in parallel to the power supply, another capacitor, say, 100nF, in parallel to the motor, and a diode between the emitter and collector of the transistor, with the cathode on the collector side (motor wire) and the anode on the emitter side (GND).

This way it must be ok.

 

[Hardwired101]

Okay so after a little digging around I believe I have found the answer to my problem. I believe this setup with the correct safety capacitors in place would do the trick. Correct me if I wrong haha.

 

[Yeti]

That LED lead structure is pure awesomeness! Congratz! All that contacts, you're a genius
When I saw the video, I was like "MUST DO IT"
So I started thinking about how I could build my version of this, and decided to start from the core: the 3 LEDS+contacts and the central motor. And I failed hard.

I already have an idea for the other 2 axis contacts, but the center one, from the motor to the leds, i just cant think of anything good...

I made 2 circular PCB, one for the negative side, the other positive. The positive one I made a triangle of copper in the center, with resistors as the bridge to the LEDs. To extend the axis of the motor (a PS2 controller motor btw) I used the transparente tube from a pen charge. Finally, a coil spring (also from a pen) on both sides of the PCBs, with a wire connected to it (positive and negative)

So when the motor is running, tube+pcb are spinning, and the spring is statical and making contact with the pcb, resulting in a circle of spinning leds!

All good in theory, but the springs kept the motor from spinning

Any suggestions on how to make that contact?

Thanks! x)
http://img828.imageshack.us/i/dsc05865n.jpg/
http://img30.imageshack.us/i/dsc05866g.jpg/
http://img838.imageshack.us/i/dsc05870.jpg/

PS: you can see 2 motors here, but only the top 1 is functional, the other is just for counterweight and support. the springs go between the motor and the pcb, around the plastic tube.

 

[louige555]

if your having trouble with led's and getting the correct voltage and whatever, i suggest you get a jay car catalogue and theres a whole page with the specs for each type of led and how to calculate the correct resistors for them.

if you cant get one, heres the formula for finding the resistor needed:


Resistor= ( (Voltage source)-(Voltage drop of LED) )/(current draw of LED)

or in other notation;

R= (VS-Vf)/If

if you dont know the voltage drop and the current draw of the led you can just ask whoever you get them from and they should know

 

[Yeti]

Oh no, I'm doin fine with turning the LEDs on, my main problem is how to make the slip contact

 

[HIMNL9]

@Hardwired101: Uhm, i mean, more like the attached one (i have also a more stable version, but for a motor, this must be ok)

 

[louige555]

sorry yeti, that was directed @13579 from the last page but it must of posted later or something and for an answer to your question, try using only one spring and use the axle of the motor as the other contact in a sorta slip ring fashion. that way there shouldn't be so much force on the motor then.

A question for HIMNL9 about that last circuit diagram you posted, I get all the symbols you have used except for the one directly right of the 100 ohm resistor, it looks like 3 way switch but not quite sure what it is.

also, another general question. if your using a 470nf capacitor or similar, will it affect the circuit if you use a 100v capacitor when it only a 12dc circuit?

 

[HIMNL9]

@ louige555: it's an N-channel mosfet

You can use a transistor, if you don't find a mosfet ..... just use one that can hold the current required from the motor, or also better a darlington (remember that under effort the motor current can be much more high than in free-running) ..... any "universal" npn darlington is ok, like TIP120, TIP121, TIP122, and so on.

If you decide to use the transistor in place of the mosfet, just connect the base to the 100ohm resistor, the emitter to GND and the collector to the motor.

 

[louige555]

thanks a dozen HIMNL9, probs gonna use a transistor as dont know many places to get a mosfet but defiantly set on using one now. :thanks:

 

[Hardwired101]

Thanks for the advice HIMNL9, Gona take a crack at this tonight. Hopefully new pics to follow soon.