Video: Dave Clausen and his LED oscilloscope project

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By Bre Pettis
Posted 2007/11/15 @ 2:08 pm
Category Electronics

A few weeks ago I gave Dave an LED matrix that I had soldered up and he made the coolest thing with it! Check out his LED oscilloscope project! – Link

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10 Responses to Video: Dave Clausen and his LED oscilloscope project

justDIY on November 15th, 2007 at 7:03 pm said:

I love shift registers, especially using them with 6 or 8 pin micro-controllers to drive lots and lots of leds.

The video was very hard to follow, I know a lot about electronics, and half the time I was lost. Anyone know what the ‘special’ led driver chip was? Was it simply a high power relay driver shift register combo like those from Allegro, or something more exotic?

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eoghain on November 15th, 2007 at 8:45 pm said:

I’d like to buy a kit for this.

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fstedie on November 15th, 2007 at 9:45 pm said:

Ditto, I’d buy a kit in a heartbeat. I’ve seen a couple of kits like this in the past but not with so many LEDs.

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JennaSys on November 15th, 2007 at 11:25 pm said:

To justDIY: I had to watch it twice to figure it out myself. I think it might be something like a MAX6969 on the 16 cathodes (sink), and then he uses the separate 8 bit register/driver combo on the anode side (source) to power the appropriate row.

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morcheeba on November 15th, 2007 at 11:31 pm said:

That’s beautiful!!

justDIY: it looks like the chip is a ST Microelectronics STP16DP05B1R. Here’s the datasheet. It looks like the hobbyist-friendly DIP package may be obsoleted, but I found stock at Mouser Electronics).

The chip does something else important: It regulates the current to the LEDs. The resistor at the bottom right corner of the chip regulates the current for *all* of the LEDs at once. Without this special feature, you would need to include resistors on each LED line — 16 in total.

here’s a big picture of the circuit

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JennaSys on November 15th, 2007 at 11:37 pm said:

To fstedie: It looks to me like he just soldered all 128 LEDs directly together. You could also get a couple of 8×8 led matrix assemblies from places like Futurlec or Sure-Electronics.

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ericskiff on November 16th, 2007 at 7:07 am said:

Heya, this is Eric Skiff of NYC Resistor, and the interviewer in this video.

Sorry we glossed over a bit of info here here- it was really meant to be an overview of shift registers, not a full implementation guide.

We’ve all gotten excited about this project, and Dave has agreed to open up his code and document everything, but needs a little help creating the schematics, etc. Zack ‘Hoeken’ Smith of RepRap will be giving a demo on Eagle at the next NYCResistor meeting so we can create the schematic, and we’ll be documenting this whole project from start to finish then.

Soon after that, we’re looking to create a kit for this project to make it easy for people to duplicate it at home. It’s a great project for learning audio processing, breadboarding using arduino, shift registers, and how to make and use an LED matrix. That, and it’s just cool. I want one of these for my desk.

Thanks for all the great feedback

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bikeK on November 16th, 2007 at 9:27 am said:

That is super fun! I need a LED circuit designer!

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fstedie on November 18th, 2007 at 8:32 am said:

JennaSys: Thanks for the info on the LED suppliers. However, that is not the hard part, it is a kit for the electronics for driving the LEDs that I’m really interested in

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tgm33@hotmail.com on November 21st, 2007 at 6:02 am said:

Thanks for the great project! I just got an Arduino and am wanting to make an LED sign for my kitchen. I want to make a sign with a button that switches between different sayings and this looks like a way to do it. Please make a kit!

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