MSP430 based intelligent fan controller

Kenneth needed to tame an old PC that was just too loud. He designed a fan controller based on the 16bit MSP430 microcontroller that adjusts the speed of 3 fans depending on the temperature of the CPU. Source code and schematics are available.

During the Maker Faire Salvage Crawl last month, I picked up a kiosk-size industrial computer for $20.  All well and good, except that the BIOS in it made no effort to control the fan speeds, and instead simply ran all three cooling fans at full blast.  This was unpleasantly loud, so I decided to simply build my own fan controller, using an MSP430, so I could easily monitor the system temperature and adjust the fan speeds accordingly.

DIY electronic derailleur for the back-wheel bicycle transmission

Here is an instructable on how to add a servo motor to your back-wheel derailleur with electronic control. This is one part of a much larger fully automatic bicycle project to make gears change automatically based on parameters such as heart rate, cadence, incline, speed, gps, etc…

Stained hardwood case for the Bus Pirate v4

Here’s a stained maple-wood case for the Bus pirate v4, milled by Vince at the Xerocraft hackerspace in Tuscan Arizona. The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff. It’s got a bunch of features an intrepid hacker might need to prototype their next project.

The Bus Pirate is sold as a bare board, which puts it at risk of shorts from messy work surfaces with conductive things like paper clips and staples laying around.  I’ve decided I really like this device, so I figured I’d make a case to protect it.

Check out our workshop video about cases, and many posts with community built cases for our projects.

You can get a Bus Pirate v4 for $40, including worldwide shipping.

Via the forum.

PARTS LIBRARY: Bourns 3306F trimmer resistor

After a few problems with standard Eagle trimmer footprints, we added the Bourns 3306F trimmer to our Eagle parts library. It seems to be a pretty common-ground footprint. We used a larger than recommended pin-hole diameter so it will work with other common trimmers too.

We use trimmers as adjustable voltage dividers, such as for contrast adjustment on HD44780 LCDs. They can also be adjustable resistors when the value needed is not clearly defined, like the backlight current adjustment on the USB LCD Backpack. Generally trimmers are rated for around 1/5th Watt.

Find out where to buy these and other parts on the partlist wiki.

3D Model: USB IR Toy v3 with remote

Today we made a 3D scene of the revised PCB for the USB IR Toy with remote that we’ll use in our new sales page. The USB IR Toy was not changed electrically, it was only moved to larger PCB with mounting holes. With the USB IR Toy you can use a remote control with your computer, view infrared signals on a logic analyzer, capture and replay remote signals.

Check out our tutorial on how to build 3D models from Cadsoft Eagle board files, as well as the tutorial on how to render life like images with Kerkythea.

The models will be published in the Dangerous Prototypes 3D warehouse collection. They are also uploaded to our SVN. You can find them inside the “art” folders in the respective project folders

PIC16F882 development board for workshops

Here’s an Arduino styled PIC16F882 development board built for a university microcontroller noob workshop. A MCP2200 USB-to-Serial IC handles the USB communication, while the board features all the support circuitry required by the PIC, such as the 5v power supply, quartz oscillator, and the ICSP programming header.

The board was initially developed for a workshop in my University for microcontroller noobs. We built more than 100 boards. The dev board was used to teach soldering as well as programming to the participants, so to keep things easy a lot of board components are TH. The MCP2200 and the LM1117-5 were pre soldered.

Check out an action pic below, with a POV-shield mounted on the board.

Continue reading “PIC16F882 development board for workshops”

App note: Useful analog circuits for digital systems

Here is an oldie, but a goodie. The late analog guru Jim Williams describes lots of analog circuits that were used in digital systems. Most of these are now integrated into digital ICs, some are still in use today.

The pristine, regimented symmetry of  digital circuit boards is occasionally interrupted by an irregular huddle of linear components. These aberrants are tolerated because they perform a variety of ancillary tasks necessary to keep the digital system running. While I certainly wouldn’t wish lifetime employment on a digital circuit board to anyone*, the reality is that the need exists.
*I suppose it’s not all that bad. Some of my best friends are digital circuits. If I had a daughter, I’d even consider letting her go out with one.

Free PCB Sunday: Pick your PCB

We go through a lot of prototype PCBs, and end up with lots of extras that we’ll never use. Every Sunday we give away a few PCBs from one of our past or future projects, or a related prototype. Our PCBs are made through Seeed Studio’s Fusion board service.

This week two random commenters will get a coupon code for the free PCB drawer tomorrow morning. Pick your own PCB.

You get unlimited free PCBs now – finish one and we’ll send you another!

Don’t forget there’s free PCBs three times every week:

Continue reading “Free PCB Sunday: Pick your PCB”

App note: 112W Boost driver for long strings of LEDs

Maxim shows how to build a 112 watt DC-DC boost driver for long strings of LEDs. The driver is current controlled,with adjustable output from 0 to 1.5Amps.

This reference design is for a high-voltage boost current source for very long strings of LEDs. Applications that use long LED strings include, but are not limited to, streetlights and parking garage lights. Long LED strings can be a very cost-effective way to drive LEDs. Also, since the LEDs will have exactly the same current, brightness variations are nicely controlled. This design has a 24V input, up to a 75V LED output, and drives 1.5A through the LED string (or strings, if paralleled). The measured input power is 115.49W and the output power is 111.6W for an efficiency of about 96.6%.

ADS-B sync and Manchester decoding in CPLD


P. Kusmierski posted an article on flipthatbit describing ADS-B sync and Manchester decoding in CPLD. The CPLD used is a Xilinx XC9536XL (which is the smaller version of the XC9572XL found in our CPLD Development Board.)

Having put together my miniADSB I needed to extract the actual data from the Manchester encoded bit streams it produced.

My idea was to join the simplicity of using a micro with the power of programmable gate arrays. In my application I want the micro to do some other work, and the CPLD should handle the simple repetitive task of looking for the ADS-B sync pattern (16 bits) and upon finding it, decode Manchester data that will follow, conveniently shifting it into the micro on the SPI bus. This way AVR is interrupted only when a new byte arrives on the SPI bus, and can handle all the other tasks meanwhile.

Kusmierski says, “Mind you, the code is still in beta and needs some work to be declared stable and fully operational. If you want to give it a try, I’ll be more than happy to hear about your thoughts/results.” The code can be found on the Hackerspace Global Grid’s Github page.

You can get your own XC9572X Development Board for $15.

App note: Interfacing a 3volt microcontroller to 5volt peripherals

It can be a challenge to interface 5volt stuff with modern 3.3volt microcontrollers like an ARM or MSP430. This app note covers several circuits for voltage translation on input, output, and bidirectional pins.

The interfacing of the 3-V MSP430x1xx and MSP430x4xx  microcontroller families to circuits with a supply of 5 V or  higher is shown. Input, output and I/O interfaces are given and explained. Worst-case design equations are provided, where  necessary. Some simple power supplies generating both voltages are shown, too.

Parallax Propeller retro pocket mini computer


Jeff Ledger wrote informing us of a retro-style computer based on the Parallax Propeller described in this Instructable. It utilizes the Pocket Mini Computer Kit from GadgetGangster. This board is based on the Propeller chip and includes VGA, audio and PS/2 keyboard ports as well as a microSD card slot and Wii controller port. The board can be programmed in BASIC (by booting from a microSD card containing the provided open source file) allowing the user to play games, run programs and experience 70s and 80s computing without fiddling with creaky old hardware and 5.25 floppy disks. (The

Via the contact form.

App note: Digital compass reference design

A PIC18F2520-based digital compass using magneto-resistive sensors to measure the magnetic field in 3-axies:

This application note will focus on a simple, low-cost, hand-held digital compass design using a Microchip PIC18F2520 microcontroller. This compass application can be  integrated into your own design, or as a building block in an advanced navigation tracking device similar to one you would find in a sporting goods store or automobile.

Workshop Update for June 8th, 2012

Today we investigated bug reports in the PC Keyboard, SPI, and logic analyzer mode of the Bus Pirate. We also continued to work on the new sales pages for our projects.

The first batch of Bus Pirate v3.6 with a new form factor is now on sale at Seeed.

Darlington transistors are added to the Part Ninja recognition firmware. Both the versions with the protection diode, and without, are supported.

Routing on the LED matrix for the DIY DP Badge is mostly done. The only thing left to do is add the microcontroller and connect it up with the 3 ‘595 serial shift registers. We chose the PIC12F1840 as it has 7kB of memory, and a whole bunch of peripherals in a tiny 8 pin package.

Warning: Ping-Pong balls are very flammable

In response to yesterdays post about the 8×16 LED matrix which used ping-pong balls as diffusers, Josh send this video and warns that the Ping-Pong balls are made of a very flammable material (nitro-cellulose). So If you are making a project using them as diffusers, keep in mind they catch fire very easily.

I had designed a kit that used ping-pong balls as LED diffusers for a nightlight, then I saw a demo of a flaming ping-pong ball at dorkbot. They’re sort of hard to light when intact, but as soon as you make a sharp corner by cutting them, an open flame catches really quickly.

Just something to keep in mind when installing an otherwise-awesome piece like this one. Don’t put it along critical fire-exit paths, because it will be its own little inferno in case of a fire.

Via the comments.

Getting your stuff built: how to shop, conduct business, stay alive, and eat your way through Shenzhen

When we Bob at the Shenzhen Maker Fair he was learning to get his portable scoreboard manufactured. He’s been blogging about his experience in China, and documented the steps he took to get his project up and running.

In 2012 I was chosen for the first year of HAXLR8R, a Chinese hardware startup accelerator to work on my product, the Portable Electronic Scoreboard. I had never been to China, and Shenzhen and Hong Kong are a mecca for electronics products. I created this blog to document my travel there and observations and lessons about working in manufacturing in China. I know that a lot of people go over there to work, but I couldn’t find the details about what steps are necessary; everything from finding an apartment and getting a phone to ordering food to getting around, to making contacts or working with local businesses.

Via Hack a Day.

Free PCB coupon via Facebook to 2 random commenters


Every Friday we give away some extra PCBs via Facebook. This post was announced on Facebook, and on Monday we’ll send coupon codes to two random commenters. More PCBs via Twitter on Tuesday and the blog every Sunday.

Don’t forget there’s free PCBs three times a every week:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”