App note: Hiccup-mode current limiting

in app notes by DP | 0 comments


This is fairly old but interesting over current protection using Hiccup-mode from Microsemi. PDF here.

Hiccup-mode is a method of operation in a power supply whose purpose is to protect the power supply from being damaged during an over-current fault condition. It also enables the power supply to restart when the fault is removed. There are other ways of protecting the power supply when it is over-loaded, such as the maximum current limiting or current foldback methods.
One of the problems resulting from over current is that excessive heat may be generated in power devices, especially MOSFET’s and Schottky diodes and the temperature of those devices may exceed their specified limits. A protection mechanism has to be used to prevent those power devices from being damaged.

Free PCB Sunday: Pick your PCB

in Free PCBs by DP | 61 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 | 61 Comments

App note: Faster switching from standard couplers

in app notes by DP | 0 comments


Here’s Vishay’s app note: Faster switching from standard couplers (PDF!):

Applications employing lower-performance “standard couplers” can still be optimized for switching speed. Thoughit can not be expected that these devices will perform to the level of specialized “high-speed” devices, they can be more than adequate for many switching applications, up to the 1 μs range. These standard couplers are the subject of discussion in this document. They fall into two general categories, 4 pin couplers, 6 pin couplers, as well as a special configuration of the single transistor coupler.

Hand powered USB charger from hacked IKEA flashlight

Werner sends this handy hack he found at IKEAHackers. Giovanni Gentile devised this simple hack which mods an IKEA Ljusa hand powered flashlight into a USB charger. “The procedure was simple, it was enough to eliminate some resistors and use a capacitor sufficient to handle the charge given by the Ljusa’s dynamo. I set the output voltage to 5 volts, and I installed a USB socket. It only remained to modify the body of the torch. Then I printed the bottom of Lyusa filament transparent leaving only the space for the female USB plug.”

Via the contact form.

Solar scare mosquito

in DIY by DP | 5 comments

Mosquito control Device

Here’s a cool Solar scare mosquito project by Gallactronics.  He writes a complete step-by-step instructions here:

So I built a device that generates air bubbles at regular intervals and effectively produces ripples up to a radius of 2 meters (sufficient for most urban water bodies). The device automatically switches on when it comes in contact with water an alarm alerts if the water body dries up or someone tries to remove the device from water. At less than $10, the device is cost effective and being solar powered, it is energy independent and maintenance-free.

Check out the video after the break.
Continue reading →

Posted in DIY | Tagged , | 5 Comments

Free PCB coupon via Facebook to 2 random commenters

in Free PCBs by DP | 3 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 to 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 | 3 Comments

Week in (p)review July 18, 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

60+ FPS with OLED and Bus Pirate

in Bus Pirate, project logs by DP | 0 comments

An update on previous 1.3”OLED with SSD1306 controlled by Bus Pirate post, Markus writes:

By changing the default serial connection speed between the PC and the Bus Pirate from 115200 to 1000000 baud, the frame rate is now increased to 60+ FPS :)

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

Solar tracking device using MSP430

in hacks, MSP430 by DP | 0 comments

vigneshraja wrote this Instructable detailing his solar tracking device using MSP430:

Hi i am showing my solar tracking project for solar panel. The two LDRs are connected to both edges of the solar it can able to follow sun direction from east side sunrise to until west side sun set. this project find more light intensity area so it help the solar panel to produce maximum power. the two LDRs analog signal are converted into digital signal in MSP430G2231. the converted values are compared continuously in MSP430G2231 and correspondingly which LDR value is higher that side solar panel will turn. let us see the circuit diagram and programming code for this project.

WordPress reinstall and server update complete

in site by Ian | 0 comments


Comments have been hosed for the last few days, and posting became impossible. This happened about a year and a half ago according to the site changlog. Everything seems to be working now, please hit us up if you notice any problems.

It’s not clear what caused it. Like last time, a complete reinstall of WordPress solved the problem of comment and posting timeouts. A look through the code didn’t reveal any common exploits. It could be an interaction with our extreme awesome server setup, or maybe WordPress just gathers crud after years of updates.

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Bus Pirate v3.8 free PCB build

in builds, Bus Pirate by DP | 2 comments


Mikelelere built a free Bus Pirate v3.8 PCB.  The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff.

I eventually managed to get all the required parts to assemble the BP v3.8 free PCB I received a couple of months ago. The microusb connector was such a PITA to solder!! I definitely prefer the good old miniusb connectors. They’re much easier to solder and way much sturdier. Anyway thanks DP for the free PCB!

Via the forum.

If you build a free PCB we’ll send you another one! Blog about it, post a picture on Flicker, whatever – we’ll send you a coupon code for the free PCB drawer.

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

Reinstalling to clear hacks, cracks, scripts, other bugs

in site by Ian | 3 comments

Commenting is timing out, and the back end is really slow. Additionally we’re having daily down time during scheduled database checks. I’m currently making a full backup snapshot, then I will completely clear out WordPress and reinstall the blog from scratch. It should go smoothly, except I have to do it all from China’s terrible internet, it could just stop working at any time.

This happened previously in December 2012 according to the site history. Its tough to say if it is a SQL injection attack or site hack causing issues, or just crud built up from years of WordPress updates. To start, I’ll clear out the files and poke around the database. Expect minor outages today.

Posted in site | Tagged , | 3 Comments

A DIY laser engraver build using DVD and CD-ROM/writer

in DIY, tools by DP | 1 comment

Laser Engraver 38x38_cdrom_1

Here’s a DIY 38mm x 38mm laser engraver build using CD-ROM/writer on ATmega328p by Davide Gironi:

A laser engraving machine, is a tool that uses lasers to engrave an object.
To build this tool I’ve used two old CD-ROM writer that lays around in my garage.
The X/Y positioning system it is build using the CD-ROM motor assembly. For the engraving laser i use the CD-ROM writer laser.
With this hardware the engraving area are will be almost 38mm x 38mm.

Check out the video after the break. Continue reading →

#FreePCB via Twitter to 2 random RTs

in Free PCBs by DP | 0 comments


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.

free PCB drawer: Box of PCBs

in Free PCBs, PCBs by DP | 8 comments


Bus Pirate v3.8 PCB and USB IR Toy v3 PCB are available now in the free PCB drawer.

Every  Friday we give away PCBs via Facebook, via Twitter on Tuesday,  and the blog every Sunday.

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

Posted in Free PCBs, PCBs | Tagged | 8 Comments

PIC32 oscilloscope

in hacks, oscilloscope by DP | 1 comment


Bruce Land writes:

Turns out that the DMA channels on a PIC32 can move data from the ADC using the ADC done interrupt flag, but without wasting time in an ISR. The ADC can be triggered by a timer interrupt flag, again without software intervention. Doing this means that you can blast ADC into memory at just under a Megasample/sec with NO software overhead!
Using another DMA channel to feed memory to a buffered SPI port means that video data can be streamed to a TV with less than 7% software overhead, sustaining a 5 megabit/sec pixel rate. Most of the video overhead is in the SYNC generator state machine ISR. But the rigid NTSC time requirements are easy to meet because all the actual SYNC generation and video timing are also done completely in hardware with no software intervention. One timer triggers two output pulse generators, one to generate SYNC, one to time the video “backporch”.
When the backporch pulse gen times out, it triggers the video DMA burst from the frame buffer in memory to the SPI port.
A simple 3 resistor DAC combines the SYNC and video stream. Resolution is 256×200. There is plenty of CPU left for FFT or game generation.

Via Hacked Gadgets.

Check out the video after the break. Continue reading →

Posted in hacks, oscilloscope | Tagged , | 1 Comment