The LED Artist - blog » Project

Pocket High Voltage Generator Quick Build

The LED Artist — Thu, 04 Oct 2018 02:05:27 +0000

- There’s an update to this post, including PCB design files. -

There are times you find yourself looking for a relatively high voltage (100V to 200V often in my case) but low current DC power supply. I have zener diodes that are higher than 30V, which makes the lab supply useless, and filament LEDs with forward voltage over 60V. When I need to test them quickly, I used to hook up a simple rectifier circuit to a variable AC power supply (nothing more than a slidac with isolation transformer). While this gets job done, the setup is capable of supplying much too high current (1A or more), so I was always very nervous and extra careful in handling the circuit. All I need is a little HV generator that gives me around 200V DC and only capable of supplying a milliamp or less. Realizing that I do have such design available – one of the Nixie supply circuit – I just decided to put one together to use.

Pocket HV Generator schematics

Quick & dirty build of the tool.

A single AA battery seems to be enough to generate over 200V on the output with no load. But the output quickly lowers when you draw 0.4mA. So it feels pretty safe to handle this casually, and I can only feel a bit of tingling, not electric shock when I touch the output terminals. The tool proved to be quite handy and useful in testing variety of things:

Zener diodes (zener voltage)
Switching diodes (reverse breakdown voltage)
Filament LEDs (forward voltage)
Regular LEDs (forward voltage – yes it’s ok to use this tool, since it’ll only give less than 1mA even at 2-3V)
BJTs (breakdown voltages)
Neon & Nixie tubes (not very bright, but you can tell if one works or not)

Pocket HV Generator testing a zener diode

Pocket HV Generator testing a Nixie tube

This is one of the most useful tools that I’ve made. And it only took a couple of hours to put it together.

Audio Interface for Aurora – Through-hole version

The LED Artist — Sun, 17 Feb 2013 05:19:04 +0000

This Interface turns Aurora 9×18 mk2, Aurora 18×18 or Aurora 12 bar into the ultimate color organ. This is the through-hole only version of the same exact circuit as the original Audio Interface.

You can watch the video here.

The interface goes between the power cable and Aurora, using Molex 3 pin connectors. The interface has a 3.5mm stereo audio jack, so you can connect any audio output. There’s a potentiometer to adjust the sensitivity level as well.
Aurora 12 bar, Aurora 9×18 mk2 and Aurora 18×18 have audio or “color organ” modes, which you can select by either pushing the on board button or using a remote control (remote not on Aurora 12 bar).

- Schematics
- Audio Interface Part Placment Guide

Complete kit includes the 3 pin connection cable pictured (other cables are not included).

*** Purchase Here ***

Some Old Works of Mine

The LED Artist — Fri, 03 Aug 2012 05:10:15 +0000

I was doing some clean up and found some old works from years ago…

The one above is a multi-purpose PIC pad using PIC16F627. This was an exercise of multiplexing 7 segment LEDs and button matrix using the same set of I/O pins. I wrote code to make it work as a timer and organ (more like a beeper with notes). 2 AA battery holder was connected to it, but obviously lost.

This was done in April of 2003. Before Arduino and all that good stuff was available. Home etched and hand drilled PCB. What’s amazing to me now is that I designed the PCB in Adobe Illustrator! I did not have a CAD software.

> PCB Layout

Next up is my very first LED project using PIC microcontroller, which was done right around the same time as the pad above.

> Schematic
> PCB Layout

I used four microcontrollers on this one. three controlling LEDs, and another one controlling them. The center one is the “master”, sending command to the other controllers to orchestrate the animation. The three “slaves” are just controlling the LEDs as they are commanded. The setup seems more complicated than my recent projects, but back then I was literally applying “divide and conquer” method to the circuit design.
When I first envisioned this one, I had no knowledge of microcontroller. I had some electronics experience and knew how to use logic ICs, however it quickly became clear that what I wanted to do was too complicated to accomplish with logic ICs. So that prompted me to look around, which led me to BASIC Stamp. BASIC Stamp, for those who never hard of it, it’s kind of like a pre-Arduino. You can write the code in BASIC language and upload it to the chip over serial cable. It was easy to use, but the processor was very slow.
Faced by the limitation I decided to learn to code PIC microcontroller directly. It took me a while to get into, but I managed.

I made a revision of the same circuit, multiplying the number of LEDs by using a complementary drive approach. (July 2003)

> Schematic
> PCB Layout

After this prototype, I decided to move on up to manufactured PCB. Found a free PCB design software (called Osmond PCB – which I still use), and start having my PCB made by a factory. This enabled me to design with fine traces and more precision.

The First batch of New Aurora Shipped

The LED Artist — Fri, 13 Apr 2012 20:49:12 +0000

Many thanks to your support, the first batch of the new Aurora kits shipped out yesterday. There are a few more orders left to ship, however due to the shortage of a part (sorry I did not expect to run out of parts) the rest of orders will have to ship next Tuesday.

I will be updating my instructables to include new firmware, but meanwhile here are the files you need to program the PICs on the new Aurora’s.

There are also online version of the “Part Placement Guides”.

Audio Interface for Aurora

The LED Artist — Wed, 04 Apr 2012 23:14:47 +0000

This Audio Interface turns Aurora 9×18 mk2 and Aurora 18×18 and Aurora 12 bar into the ultimate color organs.

You can watch the video here.

The interface goes between the power cable and Aurora, using Molex 3 pin connectors. The interface has a 3.5mm stereo audio jack, so you can connect any audio output. There’s a thumb-wheel style trim pot to adjust the sensitivity level as well.
New Aurora 9×18 mk2 and Aurora 18×18 have audio or “color organ” modes, which you can select by either pushing the on board button or using a remote control.

*** Please check out the through hole version of Audio Interface here ***

- Download the soldering/assembly guide: Audio_Interface-PartPlacement

*** This item has been replaced by through hole version – see it here ***

Aurora 18×18 Final Preview

The LED Artist — Fri, 30 Mar 2012 03:56:05 +0000

Here are some pictures of the final version of Aurora 18×18. Production PCBs will be here in 2 weeks time, and I will start shipping the kits as soon as I have the PCBs.

Interested in building one? See here for the pre-order deal.

Aurora 9×18 mk2 sneak preview

The LED Artist — Sun, 18 Mar 2012 16:06:41 +0000

The “new & improved” version of Aurora 9×18 is almost ready to be released.

The overall dimension (4.3 inch diameter), LED layout, PWM capabilities are all exactly the same as the original. However the PIC microcontroller has been replaced with a newer one (PIC24FV16KA301), which simplifies the driver circuit a bit. The new version also has an IR (Infra-red) remote receiver, so you can control it via any universal (or Sony TV) remote controllers.

There is another, new function that adds new excitement to Aurora – audio interface. With an optional Audio Interface (will be available as a separate option), you can connect Aurora 9×18 mk2 to any audio sources. Aurora 9×18 mk2 will then give whole new dimension to your music listening experience.

Photos and video of the working prototype will be posted very soon…

The original Aurora 9x18

Now I need your help to bring Aurora 9×18 mk2 into self assemble kits like other Aurora’s. In order to do that I need a small capital to start the production of PCBs, etc. So I’m offering a “pre-order” deal to speed things along.

Please view the post here about the pre-order deal. Hope you can help.

Aurora mini 18

The LED Artist — Sat, 22 Oct 2011 07:20:39 +0000

Aurora mini 18 is only 2 inches in diameter, yet controls 18 full-color (RGB) LEDs individually. The technology that enables this little thing is as amazing as the lights it produces.

Please review the instructables before purchase – assembly requires soldering skill. You will also need PIC programmer such as PICKit 3, ICD 2, ICD 3 (PICKit 2 doesn’t work with the PIC used). If you don’t have a programmer, you can purchase the PIC programmed with the latest firmware. (The PIC will be soldered to the PCB)

- Detailed technical information at instructables.com

- Aurora mini 18 part placement chart (PDF)

* Firmware update – download here *

*** Purchase Here ***

Two LED Blinky

The LED Artist — Sun, 08 Nov 2009 15:32:40 +0000

This is the simplest circuit to make two LED blink back and forth. The technical term for this circuit is “astable multivibrator”.

It’s really easy to put together, with only 10 parts.

[Part List]

2 x LEDs – any color. Red, yellow, green, blue…
2 x NPN transistors – just about any small transistor. I used PN2222A, but you can use 2N3904, 2N4401, etc.
2 x Capacitor – around 10 – 22 uF, 6V or higher than power supply voltage. Electrolytic capacitors are the easiest to find. The larger the capacitance the slower the blinking.
2 x 220 ohm resisters – anything from 200 to 1k ohm of any type should work.
2 x 47k ohm resisters – anything from 22k to 100k ohm should work. Value of these changes the timing of blinking (larger the value, slower the blinking).

You can easily obtain the parts from your local Redioshack.