Categories

BGA Reballing Practice Kit

Posted on Wednesday, March 29th, 2017 in Chips, components by DP | No Comments

BGA

@joegrand tweeted, “Practicing BGA reballing with the @dangerousproto BGA Reballing Practice Kit.”

More resources and instructions available here.

Get your own kit for $79 at Seeed.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, March 28th, 2017 in Free PCBs by DP | No Comments

IRToy-600x369

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 Sunday: Pick your PCB

Posted on Sunday, March 26th, 2017 in Free PCBs by DP | 33 Comments

BP-600x373

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:

(more…)

App note: Low-power battery temperature monitoring

Posted on Sunday, March 26th, 2017 in app notes by DP | No Comments

an_ti_sbva048

Low current consumption temperature battery monitoring TMP303 from Texas Instruments. Link here (PDF)

Charging a battery cannot be independent of temperature. In fact, most batteries specify a range of temperatures where charging is permitted. Charging outside these bounds risks damage, failure or worse. To prevent charging when the temperature is too hot or too cold, a temperature sensor and corresponding circuitry are required to disable the charging circuit accordingly. Some temperature sensors like TMP303 already incorporate this functionality. TMP303 monitors the local temperature and asserts its output when the temperature rises above or falls below factory-programmed trip points. This output signal is used to disable the charging circuit.

App note: Stopping reverse current flow in standard hot swap applications

Posted on Sunday, March 26th, 2017 in app notes by DP | No Comments

an_ti_snva673

Application report from Texas Instruments about a simple circuit that blocks reverse currents. Link here (PDF)

The proposed circuit uses an inexpensive operational amplifier to sense the condition of the output voltage exceeding the input voltage, and subsequently disable the hot swap controller, stopping the flow of reverse current (current flow from the output (load) into the input (supply)). The device used for testing this method is the LM5069, configured to provide hot swap control of input voltages from 11V to 22V to a load capacitor of 220 µF. A schematic of the solution and results are provided.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, March 24th, 2017 in Free PCBs by DP | 1 Comment

BP

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. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

(more…)

GPS tracking with an MSP430F5510 over GPRS

Posted on Friday, March 24th, 2017 in MSP430 by DP | No Comments

telit_cps_gprs_msp430_tracker

Bluehash over at 43oh.com writes:

I found a tiny gem while browsing Github for MSP430 projects. This one is a GPS tracker based on a MSP430F5510 with a GPRS cellular connection for reporting and command input. The GPS is a FGPMMOPA6H from GlobalTop and the GPRS module is a SIM900 from Simcom.
The Github link has details from code to schematics and board files.

More details at 43oh.com

The 2017 Hackaday Prize

Posted on Thursday, March 23rd, 2017 in contest by DP | 1 Comment

2017-hackaday-prize-launch-blogview

Hackaday just launched the 2017 Hackaday Prize, “Build Something That Matters”

Hackaday is calling for the curious, the creative, the determined. The Hackaday Prize is for creating for social change in order to transform the world. Using your hardware and programming knowledge on top of your scientific, design, and mechanical abilities, you will innovate to make an impact in peoples’ lives.

Prizes total over $250,000:

$120,000 goes to top 120 finalists ($1,000 each)
$50,000 Grand Prize
$30,000 Best Product Prize
$20,000 2nd Place
$15,000 3rd Place
$10,000 4th Place
$5,000 5th Place

It’s time to leverage your talent and find solutions to address a problem facing humanity today.

Full details and how to enter: Hackaday.io/prize

Check out the video after the break. (more…)

DIY programming adapters

Posted on Thursday, March 23rd, 2017 in Prototypes, testing by DP | No Comments

4p_pogo_before-1080x675

Sjaak writes:

Today came in a new batch of PCBs from DirtyPCB.com, of which one is a new revision of the BlackMagicProbe. This revision is almost the same except it has a polyfuse in its powersupply to the target, a dedicated voltage regulator instead of P-FET, its programming header on the 90 degree on the side and a jumper for entering DFU mode. All this goodness is contained in less 5×2 cm PCB space, so quite a bit of PCB estate is left for other purposes and I used panelizing in EAGLE to try another brainfart of mine.
In most DIY projects where pogo pins are used people solder them directly to a wire or pad on a PCB. Despite it looks like it is the way to go, it isn’t. Pogo pins tend to wear out relative quickly as they are only rated for a couple of hundred ‘compressions’, also solder can sip into the pin and ruin its spring.

More details at smdprutser.nl.

#FreePCB via Twitter to 2 random RTs

Posted on Tuesday, March 21st, 2017 in Free PCBs by DP | No Comments

IRToy-600x369

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.

Practical RF filter design

Posted on Monday, March 20th, 2017 in RF by DP | No Comments

Craig writes, “RF filter design is a piece of cake these days thanks to computer design and simulation tools. But actually realizing the simulated filter response in the real world can be a completely different matter! This video provides an introduction to practical RF filter design by building, testing, and tweaking a 137MHz bandpass filter suitable for NOAA APT satellite reception.”

More info at Analog Zoo homepage.

Inside the vintage 74181 ALU chip: how it works and why it’s so strange

Posted on Monday, March 20th, 2017 in Chips, reversed by DP | 3 Comments

pics-sn74ls181-600

Ken Shirriff writes:

The 74181 ALU (arithmetic/logic unit) chip powered many of the minicomputers of the 1970s: it provided fast 4-bit arithmetic and logic functions, and could be combined to handle larger words, making it a key part of many CPUs. But if you look at the chip more closely, there are a few mysteries. It implements addition, subtraction, and the Boolean functions you’d expect, but why does it provide several bizarre functions such as “A plus (A and not B)”? And if you look at the circuit diagram (below), why does it look like a random pile of gates rather than being built from standard full adder circuits. In this article, I explain that the 74181’s set of functions isn’t arbitrary but has a logical explanation. And I show how the 74181 implements carry lookahead for high speed, resulting in its complex gate structure.

More details at Ken Shirriff’s blog.

Free PCB Sunday: Pick your PCB

Posted on Sunday, March 19th, 2017 in Free PCBs by DP | 22 Comments

BP-600x373

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:

(more…)

App note: Fast Rail-to-Rail operational amplifiers ease design constraints in low voltage high speed systems

Posted on Sunday, March 19th, 2017 in app notes by DP | No Comments

an_ad_an417

Migration to lower rail voltages considerations on operational amplifier designs an Application note from Analog Devices. Link here (PDF)

Movement towards lower power supply voltages is driven by the demand that systems consume less and less power coupled with the desire to reduce the number of power supply voltages in the system. Lowering power supply voltages and reducing the number of supplies has obvious advantages. One such advantage is to lower system power consumption. This has the additional benefit of saving space. Lowering overall power consumption has a residual benefit in that there may no longer be a need for cooling fans in the system.

However, as the traditional system power supply voltages of ±15 V and ±12 V give way to lower bipolar supplies of ±5 V and single supplies of +5 V and +3.3 V, it is necessary for circuit designers to understand that designing in this new environment is not simply a matter of finding components that are specified to operate at lower voltages. Not all design principles used in the past can be directly translated to a lower voltage environment.

Reducing the power supply voltage to a typical op amp has a number of effects. Obviously, the signal swings both at the input and output are reduced. The required headroom between signal and rail (typically 1 V to 2 V in conventional amplifiers), which is of lesser importance with power supplies of ±15 V, now drastically reduces the usable signal range. While this reduction does not normally increase noise levels in the system, signal-to noise ratios will be degraded. Because the designer can no longer use techniques such as increasing power supply voltages and signal swings in order to “swamp” noise levels, greater attention must be paid to noise levels in the system.

App note: Resolution enhancements of digital potentiometers with multiple devices

Posted on Sunday, March 19th, 2017 in app notes by DP | No Comments

an_ad_an582

An old application note from Analog Devices about configuring multiple digital potentiometers to improve resolution, accuracy and programming complexity might add-up to the mix though. Link here (PDF)

Digital potentiometers usually come with standard resistance values of 10k, 100k, and 1MW at a given number of adjustable steps. If an application requires a resistance range that falls between these values, users will most likely apply a part with a resistance larger than needed scarifying resolution. Fortunately, users can parallel, stack, or cascade multiple digital potentiometers to optimize the resolution for a given application. In this article, we will share some of the ideas that may solve the challenge.

USB Infrared Toy free PCB build

Posted on Saturday, March 18th, 2017 in builds by DP | No Comments

17342487_10155138054486880_932211580759861602_n

Ben Kazemi built a free USB IR Toy PCB. 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 control buttons.

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.

5V Regulator Cap for 9V battery

Posted on Saturday, March 18th, 2017 in DIY by DP | No Comments

Test-leads-supplied-power-by-loops-or-interconnect-wires

David Cook built a 5V regulator to sit atop a 9V battery:

For quick portable projects and temporary hacks, it is often faster to reuse a simple 5V regulator circuit than to integrate a power supply into the device design. My toolbox has an LED tester and magnifier light, so why not add a convenient 5V regulator cap to the collection? There are nicer ones on the market that have surface mount components, but half the fun of an electronics hobby is creating something basic in your own style. This double-decker board with flashing LED power indicator allowed me to experiment with flush battery snaps and board interconnects.

More details at David Cook’s Robot Room project page.

Free PCB coupon via Facebook to 2 random commenters

Posted on Friday, March 17th, 2017 in Free PCBs by DP | 2 Comments

BP

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. The coupon code usually go to Facebook ‘Other’ Messages Folder . More PCBs via Twitter on Tuesday and the blog every Sunday. Don’t forget there’s free PCBs three times every week:

(more…)

A full featured mp3 Demoboard

Posted on Thursday, March 16th, 2017 in open source by DP | No Comments

DSC_3729

Boris Landoni from Open Electronics writes about a new open source Demoboard MP3 audio player DFR0299:

Let’s test out the capabilities of the DFR0299 audio player module, an ideal choice for Arduino but also for many stand-alone applications.

In this article, we decided to design and propose a demoboard for the DFR0299 module we already used in the ‘Presepino’ project; this module will function as a development platform for various application or just to program multiple circuits in the event of small productions.

More info at Open-electronics.org.

Analyzing the vintage 8008 processor from die photos: its unusual counters

Posted on Wednesday, March 15th, 2017 in reversed by DP | 1 Comment

pics-stack-cells

Ken Shirriff writes:

The revolutionary Intel 8008 microprocessor is 45 years old today (March 13, 2017), so I figured it’s time for a blog post on reverse-engineering its internal circuits. One of the interesting things about old computers is how they implemented things in unexpected ways, and the 8008 is no exception. Compared to modern architectures, one unusual feature of the 8008 is it had an on-chip stack for subroutine calls, rather than storing the stack in RAM. And instead of using normal binary counters for the stack, the 8008 saved a few gates by using shift-register counters that generated pseudo-random values. In this article, I reverse-engineer these circuits from die photos and explain how they work.

More info at Ken Shirriff’s blog.

Next Page »

Recent Comments

  • jeanmarc78: May be a free pcb for me :)
  • Jeff Tee: Still in the race?
  • Barry: Maybe not to late Need new project Free PCB Sunday
  • Sorin: I'll like one. Will save some time in producing myself.and your might have a better quality.. next project bus pirate!!!
  • Larry Couvillion: Please oh please oh pretty please!!!!