Overclocking Arduino UNO with liquid Nitrogen


Michail likes to experiment with overclocking processors using liquid Nitrogen. He also like experimenting with MCU dev boards like the Arduino, which led to the question how far can you go overclocking this little Atmel chip? Why, you might ask. “Because I can. To learn how electronics behave at cryogenic temperatures. And just curios how much juice you can squeeze out of AVR if you push hard enough This also produced some results relevant to desktop processors overclocking with liquid Nitrogen cooling.”

For more project info, visit Michail’s website.

One dollar variable fan controller

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Mountaindude has been spending some time lately working on 12V fan controllers and thought he’d share his experiences so far.

“While trying out various computer and network gear, I quite often find the fans too loud. They are of course there for a good reason, but experience tells that the device usually works just fine with less cooling.

Going through a 7805 data sheet for other reasons, I suddenly realized that a 7805 set up in variable voltage configuration should work great as a fan controller. These 12V fans usually run just fine down to 5-6 volts, but at lower RPMs, and thus quieter. Just what was needed!”

You can find project details and schematic at Ptarmigan Labs.

Via the contact form.

Microprocessor controlled 16 line connectivity tester

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An ATmega32 based Proteus simulation of 16 line connectivity tester by Dilshan Jayakody:

The main functionality of this system is to detect open and short circuits in cables and connectors. This system can test maximum of 16 lines in each test cycle and it indicate the defective line(s) through LCD. This is customizable system and user can configure number of test lines through single push button (SW1).

Quality audio on Teensy3 with Arduino

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Paul over at Dorkbotpdx writes:

Over the last couple weeks I’ve been working on supporting quality audio (44.1 kHz, 16 bit) on Teensy3 using very simple Arduino style programming. This weekend I added buttons and knobs to control parameters….
This work is still at an early stage. I hope to publish a first alpha test version in about 1 month…

The Arduino as a simple JTAG adapter

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pesco blogged about his free  XC95144XL CPLD breakout board PCB build:

A good while ago I won one of the free PCBs regularly given away by DIY hardware shop Dangerous Prototypes. My board of choice was a CPLD breakout board, for the Xilinx XC9572XL. CPLDs are the smaller brother of FPGAs: programmable logic chips that can be made to act as any integrated circuit within the device’s limits. The XC9572XL is programmed via a standard JTAG interface. I did not have anything that speaks JTAG so went looking if my Arduino can be turned into an appropriate programmer. The solution that I found, however, did not work; so I built my own.

USB Tester OLED backpack update

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William at MobileWill posted an update on his USB Tester OLED backpack we covered previously:

There is a new firmware update for the USB Tester OLED Backpack. This update completely redesigns the display and makes use of the button.

You can find the update on github.  If you need directions on how to update: www.friedcircuits

Nibbler: Another 7400 4-bit custom CPU

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Steve at Big Mess o’ Wires writes:

I know the Open 7400 Contest is long past, but I wanted to call out a new 7400-based custom CPU I’m building. It’s a 4 bit CPU called “Nibbler”, and more info is on my web site here
My goals are to keep the chip count to an absolute minimum, while still being able to run some interesting programs like Simon or Mastermind or Hammurabi. Everything is common 7400-series parts except the RAM and ROM, and the plans call for just 16 chips, which is very lightweight compared to past custom CPUs I’ve built.

DSD block for GNU Radio

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Luke Berndt from the HackRF-dev forums has posted his work to make the functionality of DSD available to GNU Radio users in the form of a GRC block. “I have been playing around a bit and found an easy way to receive and playback digital LMR. More and more of the radio systems are going from narrow band FM to Digital. This makes it tough to listen to them on GQRX. DSD is a great program which can decoded the audio you get when you tune in a system in GQRX, but you either have to run it on another machine with a audio cable in between or figure out how to do a virtual audio cable on your machine.
Continue reading “DSD block for GNU Radio”

Dot-Matrix MSP430 alarm clock update

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Markus Gritsch posted an update on his Dot-Matrix MSP430 alarm clock we covered previously:

Using the ADC is a good suggestion. Thank you!
The clock now has an additional state after turning the flashlight off, where it displays the battery voltage in volt.
I also added an additional displaying mode where it uses dice symbols for the digits. In the following picture the time is 14:27:36 and the alarm is active (on).

Via the project log forum.

Check out the video after the break. Continue reading “Dot-Matrix MSP430 alarm clock update”

#FreePCB via Twitter to 2 random RTs

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Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters.

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

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

I2C LED Display from Hacked Voltmeter

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Tom writes:

I turned up this cool project write up that reprogrammed a cheap LED voltmeter for use as a general purpose 7 segment display with I2C communication. These voltmeters cost about $3 instead of $10 for an equivalent LED display backpack from Adafruit. NB the author used a Bus Pirate to troubleshoot the bitbanged I2C protocol!

I adapted the project for a different voltmeter using the same STM8S003F3 microcontroller but with a slightly different layout. Blog post here.

Via the forum.

Advice: what to expect when authorities confiscate your electronics


It’s unfortunate that we have to consider these matters, but with governments worldwide obsessed with violating the privacy of ordinary citizens we found a well documented post which puts some flesh on what some naively view as skeletal paranoia.

In this comprehensive article Violet Blue of ZDNet outlines the tools and techniques government agents worldwide use to extract data from and plant spyware on your devices. The article has its genesis in the plight of David Miranda, whose devices were taken by UK authorities and by law can be kept for 10 days. They explain in some detail the types of intrusions which we can except should our electronic property be misappropriated by government, including hardware and firmware mods, certificate material addition, changes to software/apps, and of course data dump.

Perilous times indeed…