Free PCB coupon via Facebook to 2 random commenters

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:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook 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.

from Dangerous Prototypes http://ift.tt/2nFgeA6

The 1 bit = 6 dB rule of thumb, revisited

stop-watch-small

Steven writes:

Almost ten years ago I wrote an entry about the “1 bit = 6 dB” rule of thumb. This rule states that for each bit you add to a signal, you add 6 dB of signal to noise ratio.
The first derivation I gave then was focused on the noise, where the noise maximal amplitude was proportional to the amplitude represented by the last bit of the (encoded) signal. Let’s now derive it from the most significant bit of the signal to its least significant.

More details at Harder, Better, Faster, Stronger blog.

from Dangerous Prototypes http://ift.tt/2o9FVeM

#FreePCB via Twitter to 2 random RTs

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.

from Dangerous Prototypes http://ift.tt/2nsIbuU

Free PCB Sunday: Pick your PCB

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:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Be sure to use a real e-mail in the address field so we can contact you with the coupon.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.
  • PCBs are scrap and have no value, due to limited supply it is not possible to replace a board lost in the post

Be the first to comment, subscribe to the RSS feed.

from Dangerous Prototypes http://ift.tt/2nCvQGt

App note: Low-power battery temperature monitoring

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.

from Dangerous Prototypes http://ift.tt/2n77UYD

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

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.

from Dangerous Prototypes http://ift.tt/2n5nTFO

Free PCB coupon via Facebook to 2 random commenters

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:

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • We’ll contact you via Facebook 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.

from Dangerous Prototypes http://ift.tt/2ng4YKt

GPS tracking with an MSP430F5510 over GPRS

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

from Dangerous Prototypes http://ift.tt/2ncYv2R

The 2017 Hackaday Prize

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.

 

from Dangerous Prototypes http://ift.tt/2o8lYkK