Electronics Just Ordered 200 SMD LEDs off of Ebay

where did you get such huge protoboard material and how much did it cost?

 

Looks good Macaba. Did you ditch the bi-colour leds?

 

Like I said earlier, 1206 is a very reasonable size to work with.

looks neat, make your own circuit board for those?

they are only 4 1/2" x 6 5/16" and I got them from radio shack for $4.xx each.

As expensive as radio shack is for everything else, their protoboards are so cheap. Not the best quality, the rings like to pull up if you heat them for too long, so you have to be good with your SMD work.

 

I certainly did. I decided I didn't want death by solder fumes.

Yep, DIY etched, doubled sided PCB's.

 

Buhaha I actually started collecting a group-order from ebay yesterday. Though it will be normal legged LEDs.... Damn bright ones! The initial idea was that I want to buy as many and as bright white leds as my budget allows and solder them to a strip-copper-board just to see how bright the matrix REALLY gets and if it's any good backlighting a PSone-display in projector.. If it's not bright enought for a projector then I'll most likely just use it as a torch or as a light in photographing

 

haha I dont think it'll be bright enough for a projector, and even if it is, you need a point light source. But it'll probaby be pretty bright if there were good LEDs.

I got the blue LEDs in the mail today, and I have 54 of them soldered on 47 more to go (yes I know thats 101, I had ~20 blue SMD leds onhand allready)

I'll solder the rest on tomorrw, and then I'll be getting some PWM controllers for a boot converter, and then ordering the passives for that, and resistors for the LEDs

Anyone know a good boost converter for going from 5v to 20v or so? the ones I'm getting in have a UVLO of 8.6v or so, so 10-12v will be the minimum running voltage for this. Thats ok for putting it in my car, but if I want to run it off of 5v that doesnt do me any good.

EDIT: nvm I was narrowing my search too much by ignoring current-mode pwm converters

 

looks cool :-D. Will you make it blink like the originals? If so, it might blow up. Be careful.

That whole thing was so stupid. Still, looks cool, though :-D.

 

The middle finger will blink on mine for sure, but why not use a 556 instead of a 555 make the rest of it blink if I want...
I finished soldering up the blue leds right now, and I gave it a test, the blues are a heck of a lot brighter then the greens, so I'll probably run those at a lot lower of a current, then the full 20 mA the greens will get.

The PWM controller should be on its way, I'll start designing the circuit for that, order passives for that, and SMD resistors for each LED string. I'll go out and buy some 2-part epoxy since I cant seem to find the last tube I had around the house, and bond the 2 boards together. If I work it right, hopefully I'll be able to put all the pwm and 556 stuff all inside the body ignignokt or on the left hand side of the main board, and I'll be able to trim the right hand board down to something small.

I'll post up some pics when I get up later, time for me to go to bed.


EDIT: got it bonded together now...
Ignignokt giving you the finger as hard as he can...


oh, and those blue ones were a bit slimmer then the greens, and gave me a bit more trouble, but I do really need a better soldering iron...

 

The AOYUE 936 is a great soldering iron for it's price... soldered plenty of 1206SMD without any trouble. the standard tip on it is 0.2mm

 

picked up a weller soldering station today, not temp controlled, but I didnt feel like paying out $200 for a decent soldering station, but I needed at least some upgrade...

becauseeeee.....
while I wait for my PWM chips and passives, I have a teaser pic for my next project...


From the top,
PIC 16F877A, one I had laying around, may or may not be used, might pick another uC, or two .
Underneath that, (in the IC tube of 20 SOIC-8 chips)
Fairchild FAN7382M

Down and to the right of that, a nice pile of RGB LEDs

The single DIP16 chip next to those, is a MAX232 (or another variety of the same family)

Below that is 5 TLC5940 chips.

To the left of those is a BQ4285 kind of dated but it'll do what I need.

To the left of that is 8 mosfets, n-channel, 60v, enough amperage, nothing special here...

Above that is the stepper motor.

Anyone else like what they see? I'm probably going to start making my own PCBs for this project. But in the past month or so, ive gotten,

1) ICD2 for programming PICs
2) Soldering station
3)storage drawers for my massive pile of chips
4) tons of LEDs from ebay
5) a few stepper motors from ebay
6) glossy photo paper for toner transfer
among other things.... this is starting to get expensive But I wont need much for the toner transfer stuff, just the boards and some chemicals.

 

hmm stepper motors. are you going to make a cnc machine?

 

I had trouble with those RGB leds off ebay. Mine didn't last long at all at 15mA Hope you have better luck!

 

Just one, Its for the RGB POV clock I mentioned earlier. I wish I had the time for a CNC machine, maybe later though

I'll remember that, and try to keep my peak current down, they are all going to be PWMed for the display anyway, I have some spares for now, and I guess I can eventually replace them with decent LEDs from a better vendor.

 

It was the ones that were PWMed that seemed to fail early I might just have had a few bad batches though, since I was having a lot of trouble with green and blue LEDs from china at that time.

 

well I allready found an SPI soic-16 replacement for the RTC with an internal TCXO, so I might as well upgrade the LEDS later. Connect it with a right angle connector, and make a bar of SMD RGB LEDs ( too many TLAs )

I'll use these throughhole ones for now as a proof of concept/testbed.

Oh, and yes, I'll be putting this in the 7-segment clock thread after I get started.

 

how fast can it spin?

 

however fast I can drive the stepper motor... I want at least 1000 rpm, but it'll depend on how fast I can drive the LEDs

I did some brainstorming/designing last night, if I want to be able to handle graphics and not just text later, I'm going to have to add some RAM to this, so it should be a bit more involved then I expected, but nothing horrible.

 

Sorry to totally go off topic...

I played around with a stepper once...I also wanted to do a POV thing. I was only able to get it to go 180 rpm. If I tried to drive it any faster, it didnt spin...

I looked at specs, and steppers seem to be rated in "pulses per second" and "degrees per pulse," but the equivalent rpm ratings were not much higher than what I got...

ANYWAY, where did you get yours/does it work well? With a load?

Thanks :-D.

 

I havent gotten around to playing with it yet, as you can see the mosfets for a h-brige are right there in the pic The one I have there is 400 steps per rev, so its speed may be limited, but I have some 7.5 degree step angle motors coming in the mail which may be better suited. Not too much is set as of now. I'm finishing up the sign and going to work on each componet of the RGB display, stepper motor, then serial comm, then interfacing to the LED drivers, then putting it all together, etc...

 

Good luck on getting a stepper motor to go that fast. It's pretty much impossible.

I played around with different driving methodologies for a large ~9 deg per step stepper motor for a while, and I don't think I ever got it to go faster than 200 rpm (and that was by riddiculously overdriving the stepper coils [5v stepper at something like 15v]).

Anyways, even if you do get it to spin that fast, there's going to be a huge ammount of electrical moise coming from the stepper coils being switched on and off at several khz. You're gonna need some big mosfets and some pretty sophisticated snubbers to make it work.