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16X PWM LED FADER(tm) now completely open source

Our 16X PWM LED FADER board is now completely open source. The firmware (mplab project in C), schematic and layout in kicad, and BOM are all available. Hopefully this project will be a good starting off point for someone needing high resolution PWM control of mosfets, and lots of them.
The brain is a dsPIC33FJ32GS608, which features 16+ PWM outputs with 1.04ns duty cycle resolution. This is used to provide full 16bit control over 16 channels, with a very fast update rate. With SPI, you can send commands fast enough to smoothly fade all 16 channels, although many fades and chases are built in. A simple command / value protocol accepts control from SPI, 5V UART, or RS232.

VMeter: USB MIDI Controller Touch Strip & Display

We’re making a new product called VMeter that’s a USB MIDI Controller Touch Strip and Display. It’s going to be sold through a new site: In addition to a music controller, it has the potential to be used as a general purpose input touch strip and output meter display. It uses a USB HID interface (like a mouse or keyboard), making it relatively easy to interface with. We’ll be publishing both the protocol and computer-side source shortly. You could even use it with an arduino if you get a USB host shield. There are 8 capacitive touch sensors on the inside, and all the raw values are sent out, making it possible to do pressure sensing and even some limited multi-touch sensing.

New Product: 16X PWM Led Fader

We’re happy to introduce a new product, the 16X PWM LED Fader. It lets you control up to 16 channels of high resolution pwm voltage for LEDs or Speed controlled DC motors. It also has a bunch of built in command shortcuts for grouping lights, and making chase and fading sequences.
16x PWM LED Fader


  • 16 channels of voltage control–mix DC motors and LEDs
  • High resolution 16bit* control enables smooth fading, precise color mixing
  • Different voltages can be used on all 16 channels (4 separate banks for simplied wiring)
  • Control via RS232 serial, 5V TTL serial or high speed SPI from arduino or other uCs
  • Fast update / communication–with SPI, all 16 channels can be smoothly swept
  • Easy built-in commands: Group lights, Fade, Chase, Blink , Sunspot
  • Up to 25V and 2A per channel (max power dependent on ambient temperature)

Euro Rack VoS Filter Now Available

The Voice of Saturn (VOS) VC Filter is now available in Euro-Rack format exclusively from a n a l o g u e h a v e n.
The VoS Voltage Controlled Filter is based around a CEM3372 filter IC (4-pole resonant low-pass filter)–the same chips found in the filters of such analog classics as the Sequential Circuits Prophet 600, Prophet T8 and Oberheim Xpander. One very cool feature of the CEM series filter chips is that as the resonance is turned up, the volume level does not drop as dramatically (as it does in other analaogs, including the famous Moog Ladder Filter).
vos euro rack filter

Scanalogic 2 Logic Analyzer Review

The Scanalog 2 is a great inexpensive tool for hobbyists looking to debug digital issues, especially if they can’t afford an oscilloscope.  Debug SPI, I2C, Serial UART, 1-Wire, Maple Bus (more to come with software updates). You can even inspect that PWM or RC servo signal to make sure your arduino is outputting what you think it should.

  • 20Msps on 4 channels
  • 1.8V – 5V level detection
  • 256k samples of storage on each line
  • Playback on all 4 lines, or just 2 while reading from other 2


  • Better Triggering
  • More flexible output–static pwm to control RC servos, for instance, or just for a clock generator.

Drag Soldering HowTo Demo

Here’s a quick video of drag soldering–a technique that enables you to quickly solder entire sides of ICs by simply dragging the iron across all the pins.  The key is starting with the right amount of solder, and adding generous flux.  The results are often better and more uniform than individual pin soldering.

A Simple Tip to Prolong Soldering Iron Tip Life

A common mistake we’ve seen in our classes–as well as from experienced ‘solderers’–is to clean the tip before putting the iron back in its stand.  This habit leaves the tip exposed to oxygen in the air which works quickly to oxidize (basically rusting) the end of the tip.  Almost all metals oxidize in air, and they do so much faster at higher temperatures.  When your tip is thoroughly oxidized, it will look burnt, and no solder will stick to it. And if solder won’t stick to it, you won’t be able to create a “heat bridge” of solder between the iron and part, and very little heat will transfer.
To avoid this, coat the tip with a large blob of solder every time before returning it to its stand.  While flux in the solder gradually eats away at the tip, oxidation will cause problems much faster.

You may notice that new tips actually come coated with solder. We’ve seen manufacturer documentation recommending that you hold solder against a new tip the first time you heat it up so that the tip gets coated as soon as it’s hot enough to melt solder.
Cleaning tip: If your tip is starting to look brown, and won’t ‘hold’ solder, or the solder acts like water on a freshly waxed car, you can help restore it by repeatedly applying solder and wiping it off.  The flux in the solder acts like a cleaning against against the built up oxides.  It may take 20 or more cycles of this to get the tip back into shape.

Controlling a Hand Drill with Arduino to Spool Solder

Here’s an instructable showing how to Control a Hand Drill with an Arduino / roboduino to spool solder. This may not be on the top of everyone’s project list, but a hand drill is strong enough to do a lot of tasks, so we hope this will be helpful to someone with another project idea,… maybe spooling guitar pickups.
Rather than use TRIACs to mess with the 120VAC, we found a servo was an easy and safe way to control the drill’s trigger / throttle.  The setup also uses a home made optical encoder that triggers an interrupt in the arduino code.  The code is available Solder_spooler_v3_pde, and contains some useful bits like lookup-table speed control, state machine menu system, and interrupt based speed sensing.


Use Multimeter Beep to Find SMT LED Polarity

While SMT leds typically have a dot or small green line indicating their cathode, it can be hard to remember.  A quick way to test a LED is by touching the ends with a multimeter in ‘Continuity Test’ mode.  The multimeter generates a small voltage in order to detect a closed circuit, and this is enough to light the LED.  Although we couldn’t burn out any LEDs with this Fluke, there’s no guarantee your meter won’t over-do the current, so we recommend doing just a quick touch, or putting a resistor in line.


CuriousInventor launched in late 2006 (pre-arduino era!) as a place to enable hobbyists, students, and musicians to create their own technology. We sold open-source kits and tools, and offered numerous guides & videos on things like soldering, metal working, screws, electronics, and more. 

The store is now mostly empty, but we’ve kept the product pages and guides up since they have useful information. Many of our guides and videos still rank on the first page of google searches and have been seen millions of times. Content on this site and the CuriousInventor YouTube channel produced by Scott Driscoll.

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