Free PCB Sunday: Pick your PCB

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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 “Free PCB Sunday: Pick your PCB”

Chrome RTL-SDR receiver app updated


When it comes to the RTL-SDR dongle, there’s an app for that! (At least a Chrome app.) The Chrome app store has the updated RTL-SDR Radio Receiver app available for download. It’s free and open source and is written 100% in Javascript. “Receive and listen to FM and AM radio broadcasts on your browser or ChromeBook using an RTL2832U-based USB digital TV tuner.”

Source code available on Github under the Apache 2.0 license.

Via RTL-SDR.com.

App note: FlexConnect applications

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An app note (PDF!) on Microchips’ FlexConnect:

The USB protocol calls for rigid system roles to maintain order. One processor acts as the Host which issues commands to the Device. In turn, the Devices respond to the Host’s commands. This implementation operates well where there is one central processor controlling a wide variety of support devices. However, as technology has progressed, microprocessors have become embedded in many new and unique applications. With the proliferation of tablet PCs, laptops, ultrabooks, and smartphones, the system Host may not be the same device in every application. Microchip’s FlexConnect feature has been developed to allow the system to adapt to these new applications.

Homebrew audio signal generator

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Dilshan Jayakody  writes:

Audio Signal Generator (or AF Signal Generator) is often used in RF and AF base designing and experiments. In this article we introduce less complex AF signal generator based on commonly available electronic components. The heart of this AF signal generator is Intersil ICL8038 precision waveform generator/voltage controlled oscillator IC. ICL8038 is a function generator capable of producing sine, square and sawtooth waveforms at same time. In this project we combine ICL8038 with inverting and non-inverting amplifiers to get above mentioned 3 waveforms with 0° and 180° phase differences at the same time. Those inverting and non-inverting outputs help to use this AF signal generator with balanced audio systems.

All the design documents of this project are available to download at elect.wikispaces.com.

ATX breakout board bench power supply back in stock

The ATX breakout board bench power supply is back in stock at Seeed Studio. This board recycles an old computer PSU into a handy bench tool with 3.3/5/12/-12 volt supplies.

You can get one for $14 at Seeed Studio.

You can also get a Sick of Beige case for your ATX breakout board for $4 at Seeed.

Free PCB coupon via Facebook to 2 random commenters

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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:

Continue reading “Free PCB coupon via Facebook to 2 random commenters”

Week in (p)review January 09, 2015

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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

Open source Android IMSI-Catcher Detector

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The crew from SecUpwN wrote in to tell us about their free and open source project to detect IMSI-Catchers and Silent SMS attacks with your Android smartphone: The Android IMSI-Catcher Detector

Starting out on XDA Developers, our small team and me has been working on an open-source security-related Android App since the end of 2013 called the “Android IMSI-Catcher Detector” (in short: AIMSICD). Our App aims to detect and avoid fake base stations (IMSI-Catchers) or other base-stations (mobile antennas) with poor/no encryption as well as Silent/Stealth SMS. Feel invited to check out our GitHub repository landing page

Beer Pong robot

Here’s a cool VERSABALL Beer Pong robot by Empire Robotics:

The core principle behind VERSABALL is the jamming phase transition of granular materials. The green ball is filled with a sand like material. When air is pumped into the ball, the ball softens. The ball is then pushed against the target object. Pulling air out of the ball jams the sand like material together, causing the ball to harden. This transition from soft to hard creates the gripping forces.

Via Hacked Gadgets.

Bus Pirate v3.8 free PCB build

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@ced2k tweeted picture of his free Bus Pirate v3.8 PCB build.  The Bus Pirate is an open source hacker multi-tool that talks to electronic stuff.

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.

A world of MQTT on ESP8266

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Peter Scargill has written an article ‘the world of MQTT on ESP8266:

The obvious choice was a local copy of MOSQUITTO – the free package designed, apparently by Roger Light. A simple DOS application which can also act as a service. Marvellous. Now I needed to put the code into the ESP8266 – that worked – marvellous. I even developed my own little client application (well, I tarted up a demo) on Basic 4 Android (B4A). Now I needed some PC client to test the messages… not so marvellous. The command line tools provided with Mosquitto are, well, command line tools – I may be 60 but I’m still part of the pretty-coloured-buttons generation – I really would rather have as little to do with black boxes as possible. At least half of the links I tried on the web went to projects that haven’t started yet, or old ones that were dead – or just no-where. I finally settled on MQTT-SPY and I have to say.. it’s lovely both in operation and visually. MQTT messages are really trivial comprising a topic – and some content. I set up Mosquitto, subscribed to an arbitrary topic – and sent a message to it. LO AND BEHOLD it appeared at the bottom of MQTT-SPY.

iButtonLink T-Sense 1-wire sensor (Maxim DS18B20) + PIC 18F14K22

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Chas over at PNW/Electronics writes:

I came across a stash of iButton T-sense 1-wire sensors.. so I grabbed a couple and decided to check out 1-wire.
Maxim makes a 1-wire device called the DS18B20. It’s a 9-12 bit temperature sensor with the possibility of being powered by parasitic power from the data line. This cuts the signal path down to a single DQ line and a return. A company called iButtonLink produces a nice little wrapper around this device called a T-Sense. There are a couple pieces of software out there that will allow you to hook these up to monitoring systems, I don’t have any though. These devices come with a 64-bit address code and can be daisy-chained which makes having many of these devices monitored very nice.

More details on PNW Electronics blog.

#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.

CO2 meter and Xively logger with NDIR infrared sensor built on AVR ATmega328

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Davide Gironi published a new build an AVR ATmega328 based CO2, temperature and humidity logger and meter:

It logs data feed, CO2 in air in terms of ppm, temperature and humidity to a xively.com feed.
It also display realtime data to user through a 16×2 characters LCD.
This logger it is based on the xively logger you can found here

Check out the video after the break. Continue reading “CO2 meter and Xively logger with NDIR infrared sensor built on AVR ATmega328”

Reverse engineering a Beseler PM2L Color Analyzer

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Kerry Wong wrote an article on reverse engineering a Beseler PM2L Color Analyzer:

I recently acquired an old Beseler PM2L color analyzer. This kind of color analyzer was designed to analyze the color or exposure of film negatives at a certain location by comparing the intensity of the filtered light of each color channel (CMY and white). The PM2L model was made in the 70’s through early 80’s and has long become obsolete. But since it has a 931A photomultiplier tube (PMT) inside, you can easily repurpose it for other uses. And the good news is, these old color analyzers are cheap on eBay. You can usually grab one for a price cheaper than a bare PMT itself.
Here is a picture of the PM2L color analyzer I got. The cap for the magenta adjustment knob is missing. The black box in the front is the light sensor which houses the photomultiplier tube.

Check out the video after the break. Continue reading “Reverse engineering a Beseler PM2L Color Analyzer”

Location based development board

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Matt Coates of Sky Labs Electronics writes:

So here it is! Courtesy of Dangerous Prototypes Dirty PCB service, I have been able to put together and complete the testing of the first prototype of my very own location based development board. So lets talk about what you’re looking at. The board is a 4 layer PCB of dimensions 50 x 68 mm. The populated board has a maximum thickness of 9 mm. I considered using a 2 layer board, but the ground planes would not have been large enough and the substrate was too thick for the micro strip trace to the antenna to be of a realistic width.  The microcontroller is running an Arduino Bootloader and the board is pictured on 7mm standoffs that are attached using M2 screws.

Via the project log forum.

A PIC based SHF audio / video workstation

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Tekman has shared his 1.2 GHz band SHF workstation in the forum:

This is a SHF workstation that I built to work the satellite frequencies. Centered around 1.2 GHz, I used this workstation in conjunction with my dish driver software to map the sky for various Free to air and AV sats. The various band LNB’s all provide an output in the 1.2 GHz range.

Via the forum.

 

Creating Android BLE app

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Dany over at Elecfreaks writes:

If you are an electronics enthusiast, and also fond of programming, I would be very glad to share with you an Android BLE application development method, so you can integrate the phone and MCU to do some more interesting things. Right now we begin to explain how to develop an Android BLE application, and you can also refer to the official Google tutorial . This guide is a packed tutorial, which enables you to build your Android BLE application more easily and more quickly. Of course, I’ll upload my source code for everyone to share it and you can also refer to the official sample sdk/samples/android-18/legacy/BluetoothLeGatt.

Via the project log forum.

App note: Implementing the suspend indicator using microchip USB hubs

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App note(PDF!) on Microchips’ USB hubs suspend indicator feature.

The USB251xB / USB3x03 / USB253x / USB3x13 / USB46x6 product lines are a family of feature-rich, low power USB 2.0 hubs optimized for use in embedded systems where high performance and advanced functionality are critical design requirements. The USB251xB / USB3x03 / USB253x / USB3x13 / USB46x6 product lines feature a suspend indicator which can be used to signal to an embedded controller the suspend status of the hub. This feature is useful for signaling when a system should enter or exit a low power state.