Week in (p)review May 09, 2014

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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

PIC-based dumb terminal

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Charles Douvier writes:

Okay before you start; I know.. I know.. Because I’m shooting for a VT-100-ish emulation my project is technically an “intelligent” terminal but not in a sense that it runs an embedded OS/IP-based, but in the sense that it decodes ANSI ESC codes.. it’s still a freakn’ dumb terminal in my book.
I’m just about finished with the PC board for this and in the photo below is my proof of concept. All the key’s don’t work yet as I don’t have enough IO without some encoding; the keyboard is an old row/column keyboard I scored off eBay. Because I want to stick with a smaller PIC I’m going to use 74HC series logic to accomplish this, but I was considering switching to CPLD in a version 2.

USB isolator project

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Scasagrande shared his USB isolator project, that is available at Github:

I received inspiration for the project from other USB isolator projects on the internet. Mine features a few improvements to many of them:

  • USB-B and micro-USB connectors on the host (upstream) side
  • In addition to accepting power via the barrel connector (which goes through a basic 7805 low dropout linear regulator), there is also a micro-USB port for device-side power. This allows you to use the now common cell phone charger cube to power your isolated device
  • Push-button switch for easy USB disconnection events
  • Bypass jumper for linear regulator, allowing for 5V power from the barrel connector
  • Encased in a small box to protect the IC from the world

Via the project log forum.

Check out the video after the break.

Continue reading “USB isolator project”

Hacker Camp Shenzhen Day 3: Office hunting, hiring, starting companies, work visas

By ian

Ian @ Dangerous Prototypes discusses office hunting and life in Shenzhen. Jin @ FlyLin shares his experience hiring short term labor for kitting and assembly. Chester details the types of companies foreigners can start in China, and how to get a work visa. Morning discussions from Hacker Camp Shenzhen 2014, Saturday April 5th.

Presentations, pictures, and overview here.

Via Hacker Camp Shenzhen mini-site: Hacker Camp Shenzhen Day 3: Office hunting, hiring, starting companies, work visas

Taco Crawl 2014 Thursday before Maker Faire

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Every year before Maker Faire we spend a day in San Francisco to visit the Noisebridge hackerspace, Instructables, and other open hardware/DIY/hacker friendly people. Noisebridge is located in a neighborhood called the Mission District, and it has dozens of delicious Mexican taco shops called taquerias. We try to eat a carne asada taco at every shop, but there’s so many it’s an impossible challenge.

If you’re in San Francisco for the Maker Faire early please join us for the Dangerous taco crawl from Noise Bridge hacker space through the Mission District on Thursday the 15th. We’ll meet at Noise Bridge near the 16th and Mission Street BART stop at about 6pm. If you can make it please give us a shout via the contact form.

Route map below the fold. Hit us up on the contact for for a cell number if you want to track us down after the crawl is under way.

Continue reading “Taco Crawl 2014 Thursday before Maker Faire”

GIVEAWAY: Premium Make Your Own Cable Sample Pack

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Today the Premium Make Your Own Cable Kit is available at Seeed Studio. During development we ended up with tons of connectors, so we kitted them up into a sample pack. 200 cable kit sample packs are now available in the free PCB store.

If you’d like to get one now but don’t have a coupon, and we’ll give away 10 coupons to commentors in this thread tomorrow morning.

The Premium Make Your Own Cable Kit contains enough connectors to make an (almost) lifetime supply of cables for standard 0.1″ (2.54mm) headers. Choose the connector, or combination of connectors, that best fit your project. Slide the pre-crimped rainbow ribbon cable into the connector until you hear a snap. Now you’re ready to go!

The sample pack contains:

  • 2 x 2 pin crimp housing
  • 3 x 2 pin crimp housing
  • 4 x 2 pin crimp housing
  • 5 x 2 pin crimp housing
  • 6 x 2 pin crimp housing
  • 1 x 10cm cable with crimps

NEW PROTOTYPE: Premium Make Your Own Cable Kit

maker cable kit

How often have you been caught without the right cables? You can salvage an old ugly one from somewhere, or make a last minute part order that delays your project. Never again! The Premium Make Your Own Cable Kit from Dangerous Prototypes contains enough connectors to make an (almost) lifetime supply of cables for standard 0.1″ (2.54mm) headers.

After more than a year in development with Oomlout, our first “OOMP” project box is available. OOMP is a part management system we use in our own workshop to speed development. Rather than making a last minute Mouser part order, we decided we’d rather have a huge bundle of most parts already on hand.

OOMP also curtails another annoying tendency we share with a lot of hackers…the need to touch stuff. We don’t just order a single part for a new project, we order every version so we can experience them all and choose the “best fit”. With the OOMP boxes, we’ve already wandered Huaquiangbei to choose parts we think are high quality, durable, highly available, and affordable. Look for tons more OOMP boxes in the future, and please give us your suggestions too! Read about the rest of the Premium Make Your Own Cable Kit below. Continue reading “NEW PROTOTYPE: Premium Make Your Own Cable Kit”

Voltage recorder with playback

AVR-DataLogger and Voltage-Recorder

Dick Cappels wrote an article detailing his AVR data logger and voltage recorder:

The recorder includes the functionality of a data logger but also plays back recorded voltages and can perform a curve trace function.A simple file system provides for up to 128 different sequential files totaling up to 130,000 samples. At 1 sample per minute, that’s 90 days of continuous recording.

The voltage recorder is able to record one or two analog channels or positive analog voltage along with a one bit digital channel, sampled at 1 set of samples per second or 1 set of samples per minute. The analog channels are scaled from 0 to 2.5 volts in 250 even steps. The digital input is connected to the base of grounded emitter NPN transistor inverter with a threshold of about 0.5 volts.
The recorder can operate from batteries or from 12 to 18 volts applied to the power input connector.

FPGA based PlayStation portable display driver

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Kalle Hyvönen has  designed a FPGA-based display driver for driving PlayStation Portable displays:

This is a project I made quite a while back (about 7 months ago). I wanted a bigger display for a project of mine and noticed that PlayStation Portable displays (480×272 pixels) are quite cheap on eBay but they do not have an integrated controller/display driver. It seemed like a perfect project to practice using FPGAs so off I went.

Check out the video after the break. Continue reading “FPGA based PlayStation portable display driver”

Silver bullet oscilloscope IR receiver

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The crew from AnalysIR have shared a simple technique for viewing the mark and space data from IR transmission on an oscilloscope. They call it the “silver bullet” method.

The idea is to use a standard IR Led mounted into a BNC/RCA plug using a spare channel making an Oscilloscope infrared receiver. So we set about ordering the connectors, which arrived in the post today. Another way of looking at this device is as a ‘poor-mans’ IR receiver, but if you have an Oscilloscope to plug it into then maybe you are not so poor after all. The idea is to shine your IR remote control on to the IR Led while pressing a key which results in a small amount of current passing through the IR LED. This in turn creates a voltage differential across the terminals of the Led. For this to work well, you need to have the emitter of the remote control right up against the IR LED of the receiver.

The hardware consists of an LED in parallel with a 22K resistor housed inside an RCA plug which is then inserted into a BNC adapter.

Via the contact form.

Tutorial: Android and Bluetooth

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Luca Dentella has published the last part of his tutorial explaining how to develop Android applications that “talk” with embedded devices using Bluetooth. The tutorial covers basic tasks like enabling/disabling the phone’s Bluetooth adapter to advanced ones like using separate threads for blocking I/O operations.

Further information and earlier tutorial segements can be found on Luca’s Blog.

Via the contact forum.

chipKIT Project 5: Digital stopwatch on seven segment LED display

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Raj of Embedded Lab has a series of chipKIT tutorials.  This 5th project will show you how to build a digital stopwatch  on seven segment LED display with the chipKIT Uno32:

In this project, we will use the chipKIT Uno32 board to build a digital stopwatch capable of timing minutes, seconds, and 1/10th of seconds, and with a basic start and stop control feature. A MAX7219-driven 8-digit seven segment LED display is used to display the time elapsed. The Reset switch on the Uno32 board will be used to reset the current time back to 0 when the stopwatch is stopped.

TERMES – Termite-inspired robots

TERMES-Termite-Inspired-Robots

Researchers at Harvard University’s Wyss Institute for Biologically Inspired Engineering built this termite-inspired robots that build unsupervised:

Inspired by termites and their building activities, the TERMES project is working toward developing a swarm construction system in which robots cooperate to build 3D structures much larger than themselves. The current system consists of simple but autonomous mobile robots and specialized passive blocks; the robot is able to manipulate blocks to build tall structures, as well as maneuver over and around the structures it creates. A multi-robot control would allow many simultaneously active robots to cooperate in building structures.

Via Hacked Gadgets.

Check out the video after the break. Continue reading “TERMES – Termite-inspired robots”

#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.

Modify an off-the-shelf CP2102 module as an Arduino programmer

CP2102Mod

Kerry D. Wong wrote an article on how to modify a CP2102 module as an Arduino programmer:

To make it work with the Arduino bootloader, one easy approach is to disconnect the RST header pin from CP2102 pin 9 and connect it to the DTR pin (pin 28) instead. While in the Arduino schematics, the reset pin is connected to the ATmega328P pin 1 (RST) via a 100 ohm resistor, this connection is not strictly needed as pulses from the DTR pin (connected to ATmega328P pin 1 via a 100nF capacitor) will reset the MCU properly during programming. The two pictures below illustrate the connection between the module RST header and the RST pin of CP2102.

Taco Crawl 2014 Thursday before Maker Faire

Taco1

Every year before Maker Faire we spend a day in San Francisco to visit the Noisebridge hackerspace, Instructables, and other open hardware/DIY/hacker friendly people. Noisebridge is located in a neighborhood called the Mission District, and it has dozens of delicious Mexican taco shops called taquerias. We try to eat a carne asada taco at every shop, but there’s so many it’s an impossible challenge.

If you’re in San Francisco for the Maker Faire early please join us for the Dangerous taco crawl from Noise Bridge hacker space through the Mission District on Thursday the 15th. We’ll meet at Noise Bridge near the 16th and Mission Street BART stop at about 6pm. If you can make it please give us a shout via the contact form.

Make gave us two free tickets for friends, we’re going to give them away at the taco crawl. If you don’t have tickets yet let us know on Thursday and we’ll give you our extras.

Route map below the fold. Hit us up on the contact for for a cell number if you want to track us down after the crawl is under way.

Continue reading “Taco Crawl 2014 Thursday before Maker Faire”

Designing a high voltage power supply for Nixie tube projects

PCB layout for the switch-mode HV PSU

A PCB layout for the switch-mode HV PSU by Jan Rychter:

I’ve posted a page describing the design of a HV PSU (High-Voltage Power Supply) that generates up to 220V from a 12V input. In addition to that, it also provides 2*Vout (so, up to 440V, for dekatrons), and two outputs for powering digital logic: 5V and 3.3V. The primary HV boost circuit reaches 88% efficiency when going from 12V to 185V at 55mA, with a 3% output ripple.
The version I’m posting online is not perfect, but works quite well in a number of my projects. I decided I’d rather publish it as it is now rather than keep it locked forever.
It is published as Open-Source Hardware, to be used however one likes. All source design files are provided. It’s my way of paying back: I learned a lot from looking at other designs and by asking questions, so now it’s time to give back.