12 LED Charlieplexed Snowfall with AtTiny85

daaf1984:
I'm working on a PCB with SOIC and on board programming.

My width is now 12 mm and 29 cm length. I will make 20 of them. :wink:

I will post when I finish the drawing.

Dave

Hi Dave

That being the case - I might be able to treble your order if that's okay. I'll PM you, but I can see these being very handy so would be interested in grabbing 40, or at least getting 40 made if you'd prefer not to have to worry about logistics.

Cheers ! Geoff

Hello All,

I have done the prototype for the snowfall.
I've made a video of it. (at the bottom)
Note that I didn't trim the board to size.

I will also share the Fritzing file with all of you.
It's 2 layers and this is the part list:

• 1 ATTiny 45 @ 8Mhz (SMD SOIC)
• 1 100 nF capacitor (SMD 0805)
• 5 100 Ohm restistors (SMD 0805)
• 20 diffuse cold white LEDs 3mm
• JST-2 connector (optional)

I've broken out the ISP pins to the side of the board, so you clip a programmer clip on, or just solder wires to the pads and (re)program the ATTiny.

Have fun!

Fritzing Files:
Scheme: www.zwavelstokje.nl/Site/diversen/Charlie20SnowzijkantSO08-EIAJ-29cm_schema.jpg

.FZZ file: www.zwavelstokje.nl/Site/diversen/Charlie20SnowzijkantSO08-EIAJ-29cm.fzz

Ohhh nice!

How long did it take you to make the board and put it together?

funkyguy4000:
Ohhh nice!

How long did it take you to make the board and put it together?

From scratch: about 2 hours. But it was just to test.
I've ordered 30 PCBs in China today. White mask, black silk. :slight_smile:

I will post when I have them.

I've been having quite a bit of fun with this ATTiny charlieplexing. Aside from the KITT Larson scanner thing, most recently have made a little EMF detector (originally showcased here for Arduino)

With apologies for the lame iPad photo quality, here's that one constructed, and another take on the 20 LEDs, arranged in a square which runs a sketch that loops around changing direction every 0.5 to 5sec.

Dave thanks again for the original inspiration.
Geoff

charlieplexemf.JPG

The PCB's Arrived!

I ran into some difficulties;

I made pads at the side of the board to program them as ISP.
When I designed it, I didn't mention the pitch, so the ended up useless...
Or I should solder 6 wires every time to each board.

So I googled and found this: Build Your Own SOIC Progamming Clip | Hackaday

So, now I've programmed them all before I solder them. Saves me a lot of time.

Later this week I will post the pictures of the results. :wink:

Strykeroz, I know this thread is sorta old-ish but I wanted to thank you for your Larson code. I borrowed it and modified it for a 40-led circuit.
The 40 leds are my cars 3rd taillight. I will program this to be a normal brakelight but when the car is stopped, they will start scanning back and forth.

Here's a video of my circuit in action.

~Mike

Thanks for sharing Mike - that looks great. Love the soundtrack too. I'm pretty sure that high level tail light wouldn't pass a roadworthy here - but VERY pleased it's okay somewhere!

I'm overdue for an update here too I guess. Since last posting I've had two versions of the circuitboard made up at Seeed. The first was to prove that my new EagleCAD skills actually translated okay to the real world. When it came back fine I've moved to the smaller 50x31mm board in the DP sick-of-beige PCB size which is far more compact, and I added a footprint for a 2.1mm DC jack sharing the space of one of the two screw terminals.

The idea is these boards will daisy-chain together for power with the end board in a chain having a wall wart plugged in via the 2.1mm jack. Each is standalone with a diode for polarity protection. At the bottom are two groups of 0.1mm spaced terminals for the string of LEDs to connect to, via a row of holes for strain relief. The larger hole at the top centre takes a curtain hook or ring, to hold it to a curtain rail on the inside of a window.

In the attached photos you'll see two of the boards populated along with the front and back view. In the group shot the board at the upper right is the v0.1 first attempt for scale.

In coming weeks I'm going to make up these first 10 to get a look at how the massed effect appears. Once that's done I'll be ordering a batch of 50 more in black to complete the job. I'm not looking forward too much to soldering 1200 white LEDs...but it appears we do suffer for our art XD

Will post a video of the effect when done,
Geoff

Are the PCBs holes for the barrel jack the correct size? They look huge. Did you use the Adafruit Eagle library?

[quote author=Coding Badly link=topic=135596.msg1268000#msg1268000 date=1370480096]
Are the PCBs holes for the barrel jack the correct size? They look huge. Did you use the Adafruit Eagle library?
[/quote]They are huge. That's one of the libraries I have installed so it's quite possible that's where the part came from. I suspect from your observation that's a known issue?

It did work out okay though.
Geoff

strykeroz:
I suspect from your observation that's a known issue?

Well, it's known to me. I have not found anyone else who has had problems. I did create an issue for it on Github/adafruit.

It did work out okay though.

Yeah but having it the correct size (probably #) works so much better. If you want, I can dig up my version which (hopefully #) is correct.

# I have not yet made up boards since correcting the footprint.

[quote author=Coding Badly link=topic=135596.msg1268005#msg1268005 date=1370480671]
If you want, I can dig up my version which (hopefully #) is correct.

# I have not yet made up boards since correcting the footprint.
[/quote]That would be great - thanks. And happy to be the lab rat for sure.

Cheers ! Geoff

I have no idea how to extract the one part so I'm attaching the entire library.

PJ-102A is the part number. It's the Eagle Package for this...

I believe it is the same or very similar to the one you are using.

adafruit.7z (206 KB)

Time flies....

I should have posted my version long time ago...
So I will do it right now :wink:

Ik looks great Strykeroz! You did a great job.

Here are mine:

Measurements: 1x29 Cm
Used components:
• 1 ATTiny 45 @ 8Mhz (SMD SOIC)
• 1 100 nF capacitor (SMD 0805)
• 5 100 Ohm restistors (SMD 0805)
• 20 diffuse cold white LEDs 3mm

I'd just took one that wasn't cleaned up...
You can see the flux around the solder.. :wink:

Here an other picture:

I just read this entire thread. I'm impressed, you guys do awesome work.

How can I get the pcb files to have my own made?

Hi,

Thanks for your interest. I've not actually gone back to this project for several months - time flies - have a big box of LEDs sitting beside me here that needs to be assembled before December though :slight_smile:

Traxxtar:
How can I get the pcb files to have my own made?

I've just updated github with the EagleCAD schematic and board as well as a zip file that can be sent to Seeed Studios (that's where I had mine made) without any further work. Note this is still with the bigger pad Adafruit 2.1mm component discussed above and produces a board in the sick-of-beige 50x31mm shape.

Not sure if Dave has published his somewhere as yet...

Cheers ! Geoff

Hi all,

Funny, here just the same, only finished 5 of them and still need something to weatherproof it. :wink:

But I did posted my layout on the Fritzing site:
http://fritzing.org/projects/charlieplex-snowfallshooting-star-20-leds

Take a look at it and have fun with it!

Dave

daaf1984:
...and still need something to weatherproof it. :wink:

Hi Dave

I've had some success with some test circuits embedding them in casting resin (here's a link to the brand I bought but you're sure to have an equivalent local to you). After several months the resin remains clear, and the circuit protected. I can see some of the circuitry has changed colour due, I presume, to corrosion where I didn't get all the flux off.

Overall I think that's a method I'll continue to use for weatherproofing LED circuits, and my results can only improve.

Cheers ! Geoff