Dave do you ever do any 'fun' projects? - Page 1
Forum section: electronics / general

author: NickS
author_rank: Unknown
timestamp: March 29, 2013, 10:36:01 pm
content: Hi Dave.I've been watching for awhile and I love the videos however I had a question, do you ever do any 'fun' projects which don't have any practical purpose?I'm a programmer by trade so electronics are purely a hobby. There aren't many practical things I need to do (I've got some LCDs that show vital server statistics but that's about it).So I end up doing things that look pretty (which the wife prefers and they are easier to justify to her).I've just finished myfor example which of course serves no purpose other than to look pretty.My next project might be a multicoloured LED table and I've been itching to computer control Christmas lights for awhile now.Dave have you ever done anything like that before?Thanks

author: Radio Tech
author_rank: Frequent Contributor
timestamp: March 30, 2013, 12:16:47 am
content: That is cool. Nice job

author: MacAttak
author_rank: Unknown
timestamp: March 30, 2013, 01:48:18 am
content: Nifty. I've been working on an 8x8x8 also, but it's the lowest priority project for me so progress is VERY slow. The testing, lead-forming, soldering, and re-testing of 512 LED's is a real test of perseverance. I get a few rows done at a time before I have to stop and do something else for a while.Neat idea of using perfboard as a platform, but it seems that would be pretty expensive, no? I'm using a wooden cigar box I picked up from the local cigar merchant. They sell them for $1.50 a box for as many as I want, and IMO I love the look and feel of those for project enclosures/platforms.What kind of circuitry did you end up using to drive it? There are many techniques out there, just curious which approach you took.

author: c4757p
author_rank: Super Contributor
timestamp: March 30, 2013, 02:02:27 am
content: An idea for constructing these: I saw quite a while ago (on YouTube IIRC) that somebody made a glass PCB by fixing very flat copper foil to a glass surface with UV-cured epoxy. Could look really cool made with SMD LEDs on glass PCBs (ABC XYZ...). Use thin glass, 6mil or 8mil traces and 0603 resistors and LEDs, and the electronic structure will be small and not get in the way. You could even stick micros on them and make the whole thing self-contained.Hmm.... I usually don't give a shit about artsy electronics projects, but it's tempting to do this now.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: March 31, 2013, 03:06:06 am
content: What about a cube made out ofITO (Indium Tin Oxide) Coated GlassorITO (Indium Tin Oxide) Coated PET Plasticthen use the SMD or OLED so that way you can get a clean view into the heart of the cube?

author: c4757p
author_rank: Super Contributor
timestamp: March 31, 2013, 03:08:57 am
content: Looks like a massive pain to work with. At least with the copper foil on glass, you can etch it traditionally. (I am seriously considering making one this way, so maybe once I've made a couple glass PCBs I'll post something about that.)

author: MacAttak
author_rank: Unknown
timestamp: March 31, 2013, 04:43:49 am
content: Those are pretty cool ideas.Along similar lines, I considered using fine conductive thread to suspend 0603 LEDs - either just solder them directly to the thread (if it's even possible), or solder to a pair of very tiny washers or even just tiny loops of solid-core wire... pretty much just giving something to tie the thread to. The suspended wires would be tensioned individually between a pair of acrylic panels (or something similar).The biggest problem with LED cubes tends to be that as they get larger, it becomes increasingly difficult to see the "far" diodes. Like trying to watch a movie in a crowded theater when you're in the back and shorter than everyone else. The sheer bulk of through-hole LEDs and their leads makes the 8x8x8 layout pretty much the upper limit of what is reasonable to build... but using smaller SMD components and novel grid structures just might make things a little bit more interesting.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: March 31, 2013, 09:10:18 am
content: The only down side to smd is that they don't diffuse as well. So you'll probably have a narrow viewing angle.

author: EEVblog
author_rank: Unknown
timestamp: March 31, 2013, 09:17:36 am
content: Quote from: NickS on March 29, 2013, 10:36:01 pmThat LED cube project of yours is not useless, it looks pretty, and that's a purpose!Every project I do (or start) is fun, otherwise I wouldn't do it.My uWatch didn't really have a practical purpose, I did it for fun.http://calcwatch.com/

author: mariush
author_rank: Super Contributor
timestamp: March 31, 2013, 04:45:17 pm
content: I actually am working towards making a rgb cube but for now I only bought 100 rgb leds to make build one 8x8 rgb matrix. It can then be extended easily to a cube, just by multiplying the design.About 12$ for the 100 leds, about 13$ for 10 large 120x180mm prototyping boards (I'll only need one but it was too cheap to not take advantage of the offer)..When they arrive I'm also going to get some shift registers and ULN2003A or ULN2804 darlington arrays from farnell to power the leds from higher voltage (thinking 12v as I have old power supplies around). A small 14pin PIC would handle the shifting of data to turn on and off leds in a row, and activating columns.. simple... the rest of the hardware would be about 5-10$.Since I got common cathode leds, I should be able to use very thin wires (each diode in a led is 10mA max, so even the common cathode wire for a row or column would only have to handle 250-300mA) for each led color and that got me thinking of using litz wires or maybe get some standard udma133/ide cables (these are awg28-awg30, 80 wires in ribbon) and make strips of four wires for each column.I wonder how thin plexiglass would work... thinking of getting a plexiglass square, drill holes to lock the led in each hole, then glue the strips of four wires on the plexiglass to look nice. Not sure now how would the light spread through the plexiglass - I might have to use a black marker to made the leds directional.Anyway, that's al

author: MacAttak
author_rank: Unknown
timestamp: March 31, 2013, 06:53:07 pm
content: I think you meant that you would have 3 wires per column (not 4), with the common cathodes tied together in rows? Otherwise you wouldn't be able to drive a single LED in the column... all of them would light up together.The plexiglass/lexan would probably act as a light pipe, which I suppose can look nice if you plan for it. I wouldn't use it for a multilayer cube though, the accumulated distortion would be pretty bad. It would be like looking through a pool of water.

author: mariush
author_rank: Super Contributor
timestamp: March 31, 2013, 08:54:15 pm
content: I'm talking about this :Each column will have 4 wires at the base (or the top, whichever way you want to view it), but the fourth wire varies in length depending of the cathodes it's supposed to join. I don't want wires on the sides... I know it would even bother me that I'll see columns with more wire than others but I'll have to live with it.Yes, I figured as much that plexiglass would spread the light. I'll have to experiment, it just seems too much of a convenient material to keep the lights evenly spread out in a 8 by 8 matrix without resorting to think solid wires, I don't like how the one at the top of this thread is made, too much visible wire.Might have to try using heathrink tubing or some other sort of tube to channel the light from the rgb led only in one direction... I'll have to see when the leds come.

author: NickS
author_rank: Unknown
timestamp: April 01, 2013, 02:48:11 am
content: Quote from: MacAttak on March 30, 2013, 01:48:18 amHaha mine is just over a year in the makings. Kept hitting minor snags and had to think of good work arounds to make it easier.Using CAT-5 to wire up the LEDs was a brilliant idea of mine which I haven't seen before. Cheap (I got 100m for $30), colour coded, thin and 8 wires means you have one per row.Quote from: MacAttak on March 30, 2013, 01:48:18 amCheap asian perf board? Nope. Cheap as chips. I epoxied two together and cable tied the cube to it. It gives the board stability without being too rigid.I did try and solder it down to the board and do the wires underneath but I quickly found out that getting 64 leads in to holes at the same time is impossible.Quote from: MacAttak on March 30, 2013, 01:48:18 am74HC595's - 8 to control the 64 columns and 1 to do the layers. Transistors on that last 595 to switch the current for the layers.Very cheap and simple.Quote from: EEVblog on March 31, 2013, 09:17:36 amHahaha of course.I mean't 'fun' as in a random person off the street could really appreciate it.Your watch would certainly meet that criteria.By the way that seems to redirect to bing.com for me which is a bit weird?

author: MacAttak
author_rank: Unknown
timestamp: April 01, 2013, 03:48:38 am
content: Ah, using 8 shift registers is a pretty standard approach, along with one more linked with a darlington array (or discreets) for common sink/source to light up one layer at a time.CAT5 wiring is brilliant by the way. Can't believe I didn't think of thatas I have a spool of the stuff leftover from when I wired my house with CAT5 to every room. It certainly beats ribbon cable or other approaches - CAT5 is very easy to work with and very tidy. RJ-45 modular jacks are also a really cheap connector (if you wanted to make it easily disconnectable for any reason).