ChronodeVFD: Wearable Electronics VFD wristwatch

in DIY by DP | 3 comments


Johngineer wrote an article detailing the build of his ChronodeVFD wristwatch:

The ChronodeVFD is a personal project I’ve been working on for a couple of months. It’s a wristwatch built around the IVL2-7/5 VFD display tube. I originally purchased a few of these tubes to build a standard desk clock, but after playing around with them, I realized I could probably build a wristwatch too. The tube has a number of features which make it more suited than most Soviet-surplus VFDs for this purpose.

Via Electronics Lab.

Posted in DIY | Tagged , , | 3 Comments

High voltage serial programming for AVR chips with the Bus Pirate

in AVR, Bus Pirate by DP | 0 comments


Leonerd writes:

I am happy to report a full success using the Bus Pirate to program HVSP on the 8- and 14-pin ATtiny chips. This requires a small additional bit of hardware, to use the AUX pin to control a +12V supply to the ‘tiny RESET line, and the 4 GPIO pins attached to the 4 HVSP control lines. It’s not the fastest way to program the chip (given as HVSP is custom 11-bit serial, requires 22 bytes of Bus Pirate control per byte written to the chip), but it works well enough to reset fuses and the like.

More detail as well as code to implement it can be found at

Get your own handy Bus Pirate for $30, including world-wide shipping. Also available from our friendly distributors.

Hacking Android on the UDOO board (for SATA and S/PDIF)

Computer engineer Primiano Tucci has been experimenting with Android on the UDOO board.

I recently came in possession of a UDOO Quad board. The hardware onboard is pretty powerful compared to many other competitor boards. Unfortunately, however, the software support for Android is lagging a bit. In particular, in the latest image shipped by UDOO (Android JB 4.3 v2.0.2) both the SATA port and the S/PDIF digital audio output are not functional. For this reason I spent some time working on a fork of the image and patched both the Kernel and the Android framework to fix it. All the work described here is based on the Android 4.3 Sources v2.0 (U-Boot, Kernel, File System) from and is open-source, maintained in my GitHub account.

For details and links to code downloads visit Primiano Tucci’s blog.

Free PCB Sunday: Pick your PCB

in Free PCBs by DP | 64 comments


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 →

Posted in Free PCBs | Tagged | 64 Comments

App note: Lithium coin-cell batteries: Predicting an application lifetime

in app notes by DP | 0 comments


An application note (PDF) from MAXIM.

The typical specification for lithium coin-cell batteries has been to provide a 10-year battery lifetime in the absence of system power. End users should evaluate the anticipated lifetime in their specific application, especially for those that exceed typical commercial environments or that need to last more than 10 years. This article gives the reader an overview of the major factors affecting the lifetime of an IC that can be powered by either the system power or a lithium battery for a backup supply.

App note: I2C interface connects compact flash Card to microcontroller

in app notes by vimark | 0 comments


CF cards needs a lot of I/O resources in order to communicate, here’s MAXIM’s solution(PDF) using their MAX7311 I/O expander to interface these type of data storage devices.

This application note explains how to use an I2C I/O extender to connect a compact-flash (CF) card to the I2C interface of a microcontroller. The software commands for reading and writing data are explained.

App note: AXI Chip2Chip reference design for real-time video

in app notes by DP | 0 comments


AXI Chip2Chip reference design for real-time video application (PDF!) from Xilinx:

The LogiCORE™ IP AXI Chip2Chip is a soft Xilinx core that provides bridging between Advanced eXtensible Interface (AXI) systems for multi-device System-On-Chip solutions. This application note provides a setup demonstrating real-time video traffic across Kintex®-7 FPGA and Zynq®-7000 All Programmable (AP) SoC boards. The setup uses the AXI Chip2Chip core for connectivity across two Xilinx boards using FMC connector cables.

App note: 8-bit RISC microcontroller

in app notes by DP | 1 comment


Here’s an app note (PDF!) for In-System Programming Solution for AVR microcontrollers from Atmel:

• Complete In-System Programming Solution for AVR Microcontrollers
• Covers All AVR Microcontrollers with In-System Programming Support
• Reprogram Both Data Flash and Parameter EEPROM Memories
• Complete Schematics for Low-cost In-System Programmer
• Simple Three-wire SPI Programming Interface

This application note shows how to design the system to support In-System Program- ming. It also shows how a low-cost In-System Programmer can be made, that will allow the target AVR microcontroller to be programmed from any PC equipped with a regular 9-pin serial port. Alternatively, the entire In-System Programmer can be built into the system allowing it to reprogram itself.

Free PCB coupon via Facebook to 2 random commenters

in Free PCBs by DP | 5 comments


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

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

Continue reading →

Posted in Free PCBs | Tagged | 5 Comments

Week in (p)review October 24, 2014

in week in review by DP | 0 comments


Here’s a summary of major developments over the last week. Free PCB Friday is coming up soon.

Coming up:

  • Free PCBs via Facebook on Friday
  • App notes on the weekend
  • Free PCB Sunday
  • Free PCBs via Twitter on Tuesday
  • Weekly roundup and preview every Friday

WiFi globalCALCnet with the Spark Core

in gadget, wireless by DP | 0 comments


A wireless calculator networking with WiFi gCn using the Spark Core.  KermMartian of Cemetech writes:

This current project achieves all the goals of that project, and more: it provides a computer-free way to connect calculators to the internet, and lets the calculators independently configure the bridge device as well. The two components that were necessary to make this work are the Spark Core firmware itself, modified and expanded from the original Arduino gCn bridge firmware, and a Bridge Configurator program written in TI-BASIC that is used to set the WiFi credentials and local and remote gCn hub names on the Spark Core.  

Check out the video after the break.

Continue reading →

Optically controlled servo motor

in hacks, PIC by DP | 0 comments


Dilshan Jayakody  writes:

This is demonstration project to control servo motor movement using physical marker and normal video camera. In this project video camera capture the movements of marker and calculate rotation angle based on that. This calculated rotation angle is feed to the servo through small MCU based interfacing unit.
In this project video processing and tracking is performed using ARToolkit and controlling of servo is carried out using PIC16F628A microcontroller. RS232 interface is use to communicate between PC and microcontroller.

DirtyPCB NanoSeeker v2.1

in, wireless by DP | 1 comment


Jon Hylands writes:

So I built a board tonight, and its working (after removing and rotating one of the h-bridge chips I put on backwards). I’ve validated that micropython works on it, and I can turn on and off the four LEDs. I’ve also successfully paired my cell phone with the bluetooth module on the board, so I’m pretty happy about that.

Posted in, wireless | Tagged | 1 Comment

Using a standard coil for NFC tag implant reading

in Chips, wireless by DP | 0 comments


Limpkin writes:

Who knew it’d be possible to use this coil to read NFC tags?
A while ago I backed the xNT campaign , which aimed at making an NTAG216 based NFC implant for different purposes. After a few months of waiting and a few weeks of trying to find someone in Switzerland willing to do the very simple implant procedure, I finally became a cyborg.

Posted in Chips, wireless | Tagged , , | Leave a comment

Update on CERN’s investment in KiCAD

in software by DP | 1 comment


From the comments on our Cadsoft Eagle review post:

Cern’s team is hard at work. You can see the list of their projects here
The code is being contributed to the official Kicad’s repository, just it may not be in the release version yet, because it is still not ready for prime time due to very wide range of subsystems that are affected (especially the entire display subsystem). You can see a short demo of push & shove router here
I tried the router a couple of months ago and it worked, however there were still some problems with display.

Short demo of push & shove router after the break.

Continue reading →

Roland SP-404 AVR custom midi control pedal

in AVR, hacks by DP | 0 comments


An open source midi controller user for the Roland SP-404 sampler by Davide Gironi:

The Roland SP-404 is a digital sampler made by Roland Corporation.
This sampler has an input midi port, and expose a set of midi commands to control the unit.
With this project user can control Roland SP-404 using a Midi Pedal.
With the pedal user can change the bank of the sampler and also switch on / off samples. It is a pedal extentions of the button matrix in front of the sampler.
Current working bank of the midi pedal extention it is show by a 7-segment digits display. User can work on the selected bank even if the SP-404 unit is showing other bank.

Check out the video after the break. Continue reading →

#FreePCB via Twitter to 2 random RTs

in Free PCBs by DP | 0 comments

irtoyv3 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.