Octopart provides historical component pricing


Greg Shikhman from Octopart writes, “Hey DP, we just launched a new feature on Octopart that we think is really cool: historical prices on chips. We’re trying to bring transparency to the chip market and we’ve already discovered some cool stuff in our data. Check it out!

The way it works is you search for your component on Octopart. When the component’s page appears, look to the right for a small graph near the unit price. Click on the graph and you open a full page graph detailing historical pricing for whatever range you select.

Via the contact form.

Free PCB coupon via Facebook to 2 random commenters

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 a every week:

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

Week in (p)review July 06, 2012

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
  • Parts on Monday
  • New 3D model on Monday
  • Free PCBs via Twitter on Tuesday
  • USB stack tutorial on Wednesday
  • Workshop video on Thursday
  • Weekly roundup and preview every Friday

What are you hacking this week?

Adaptive brightness control for seven segment LED displays

Raj made a temperature and relative humidity meter to demonstrate adaptive brightness control on a seven segment LCD. The system uses a LDR light sensor in a closed loop to continuously adjust the brightness of the LEDs.

The objective of this project is to illustrate a technique of implementing adaptive brightness control to seven segment LED displays. It consists of a closed loop system that continuously assesses ambient light condition using an inexpensive light-dependent resistor (LDR) and uses that information to adjust the brightness of the display. For the proof of concept, the technique is applied to construct a digital temperature and relative humidity meter that adapts the brightness of the seven segment LED displays to the surrounding lighting conditions.

DIY USB OTG cable connects Flash disk to Android phone

Rohit de Sa has an Android phone with a feature known as USB On The Go (OTG), allowing the phone to act as either a host or slave. Thus, it can interface with various USB devices such as mice, keyboards, etc. Since in his region a USB OTG cable is not easily available, Rohit went the DIY route and designed his own cable to interface phone and USB Flash drive. He wrote this short tutorial on his NutsAndBoltsAndFlyingSparks website detailing the project.

Via the contact form.

Workshop Update for July 5th, 2012

Today is Workshop Video Thursday so we spent a lot of time in filming and editing. We still haven’t found a great solution for the screen capture software.

Firmware development took a hit today, as we wasted most of the time following wrong assumptions. While implementing the final “menu activated” function, we somehow broke the entire menu. We had to delete today’s work, and start over.

GIVEAWAY: Little Wire USB controlled multi-tool winners

Today we announce the winners of the Little Wire USB controlled multi-tool. There were lots of great ideas for projects based on the Little Wire, thanks for your submissions.

tech2077 wins a Little Wire for his USB body monitoring system:

I would use this for a usb based body monitoring system with multiple sensors for body heat, heart rate, blood oxygen, blood pressure, ect. The device would fit on my forearm and be accessible over usb, then a graphing program on my computer would log the data every time it was attached. Would be interesting to see how different activities and times of day affect my vitals specifically.

Another winner is Ian Caister for his USB phone IO extension idea:

I have a phone that includes a built-in USB host (Nokia N8) so I would create a software interface to use the Little Wire from the phone as basically an expansion/IO port, taking advantage of the phone’s power.

Thanks to Ihsan Kehribar for supplying the free swag. Thank you for participating, there were a bunch of great ideas. As always feel free to share your projects in the forum.

The Little Wire is available for $19.00 from Seeed Studio.

Prop EKG: simple heart rhythm monitor using Parallax Propeller


RaysLogic has posted his plans for a Parallax Propeller based heart rate monitor. Dubbed the PropEKG, Ray’s design uses an AD627 instrument amplifier and TC1029 dual op amp. Data is processed by the Propeller and relayed to a Windows PC using a Parallax PropPlug (normally used for programming a Propeller chip.) The circuit is isolated from the PC for safety purposes using an H11L opto-isolator.

Ray’s website has the schematic and links to the Propeller code and the associated Windows application.

MSP430 Launchpad Logic Analyzer based on the Logic Shrimp

oPossum built a 6 channel logic analyzer booster pack for the MSP430 Launchpad. His design is inspired by the Logic Shrimp and used SPI serial interface RAM chips to store samples. The MSP430 software is SUMP compatible and works with Jawi’s OLS client.

This is a logic analyzer add-on for the TI MSP430 Launchpad. It is inspired by the Logic Shrimp – you could say it is a rip off the design – that would be quite fair.

There are a few differences in the design compared to the Logic Shrimp.

The SPI RAM chips have the SI and SO lines tied together. This reduces the pin count needed on the microcontroller…

The MSP430 can output it’s internal clock on P1.4, so this is used to clock the SPI RAM during acquisition. This feature eliminates the need for a tristate buffer between the oscillator and RAM CLK line…

With the Scanalogic 2, there are now designs for SPI SRAM-based logic analyzers for AVR, MSP430, and PICs.

WORKSHOP VIDEO #28: Exploring the serial port

While USB is all around us, the humble (virtual) serial port is still everywhere. Today we explore the serial interface on the Infrared Toy, Bus Pirate, and Logic Sniffer. See a demonstration of the binary interfaces and commands normally used only by software utilities. Grab some terminal software like Tera Term, and Hercules and follow along.

Here’s some references from the video:

You can get IR Toy v2 for $22.05, own the Bus Pirate for $30, or grab a Logic Sniffer for $50. All including free worldwide shipping.

Chumby Hackerboard – Support THS moving efforts

Tokyo HackerSpace are moving to a new place. To support this move they teamed up with Safecast to offer the Chumby HackerBoard at ~$63, which is %30 off the normal price. The Chumby HackerBoard is a single board Linux computer, with a 454 MHz ARM processor, and 64 MB of memory.

Tokyo HackerSpace in conjunction with Safecast.org Japan have a smoking deal for you! Buy a Chumby HackerBoard for only 5000 yen! That’s about $63. Save 27 dollars!! You’ll be helping our HackerSpace move into our new place.

Workshop Update for July 4th, 2012

UPS package finally corralled, and will be delivered tomorrow. A 74HCT245 will complete a long-delayed final revision of a certain secret prototype.

We prepared for tomorrows workshop video on serial port interfacing.

We arranged a giveaway for a coming week, and perhaps the first sponsor of the 2012 Open 7400 Competition.

Today we continued contacting sources for our part kit. We also had time to add the credit card sized PCB to our standard sized rectangular PCBs, as per TonyD’s suggestion in the comments.

We also continued working on the secret project’s firmware, but only to the extent that we tested it for all user interface possibilities. We also worked on updating some wiki documentation.

The HD44780 emulator went through yet another total redesign. To respect the HD44780 timings, we had to add logic devices to the project. The latest revision will feature a PIC32 in a 28pin package, a XC9536XL CPLD, and a 3v3-5v level shifter. The overall cost of these three chips is actually lower then the PIC18F2550 by itself.

Dual-tone multi-frequency signal generator and detector

Robots wrote a open source Dual-Tone Multi-Frequency signal generator and detector for his STM32 based development board. The code is available via github.

DTMF generator is based on AVR314 appnote, and the detector is my practice in signal processing using “Goertzel algorithm”. Everything is written for integer/fixedpoint arithmetics. (no floats at all)…

Generator generates signal using PWM, by changing the duty cycle each period. Two sine signals (low and high) are generated using LUT and mixed before feeding into the PWM.

Detection is done by using 8 simultaneous signal detectors. One for each frequency in dtmf. After 205samples energie of each frequency is calculated and peak detected.

Q&A with the developers of Codebender web-based Arduino IDE

Codebender is a new web-based development environment for the Arduino. Everything happens online, they even figured out how to upload new sketches from the browser. Before you groan about another locked-up software as service startup hear this: it’s open source! We talked to Codebender about the project.

Walk us through your project

Our goal is to supplement, or even replace, the Arduino IDE. I’m proud to say we are now reaching a stable beta phase, with a really great editor, Clang for improved error reporting, and we have even developed a technology that enables us to flash a USB connected Arduino straight from the browser, without the need to install any software, as well as an Ethernet TFTP bootloader that allows us (and everyone else, since it’s completely open source) to flash any Arduino with Internet connectivity anywhere in the world.

Continue reading “Q&A with the developers of Codebender web-based Arduino IDE”

OLinuXino-Micro ARM9 Linux board hits the streets

Olimex released their OLinuXino-Micro, an ARM9 development platform that supports Linux. It runs at 454 MHz, has 64 MB of RAM, an SD-card reader, TV PAL/NTSC video output, one USB High-Speed host port, and an a Pi-tossing 60 GPIO pins broken out. It’s priced around 24 Euros (30 bucks).

Via the forum.

Parallax Emic 2 text-to-speech module


Parallax has released their Emic 2 Text-to-Speech Module. The Emic 2 is a multi-language voice synthesizer that converts a stream of digital text into natural sounding speech. The module requires a 5 volt DC power supply at 30 mA, and interfaces with your project via 9600 baud asynchronous serial (TTL).

The module is capable of producing 9 different voices in both English and Spanish using the Fonix DECtalk speech syntheizer engine. The commands (described in the product brief) allow dynamic control of speech and voice characteristics, including pitch, speaking rate, and word emphasis. The on-board audio amp allows for direct connection to an 8-ohm speaker using the SP+ and SP- pins.

More details follow. Continue reading “Parallax Emic 2 text-to-speech module”

Workshop Update for July 3rd, 2012

 

We finalized part kit materials, and made a round of updates to Seeed sales pages, and the wiki. We also photographed some missing parts for the master part list wiki.

Code for the secret project is close to first full function testing. Only one large function is left to be implemented. Today we mostly debugged, and extensively tested the code.

The HD44780 emulator project was giving us a lot of problems with read function timings. That is until Arhi reminded us that all read operations are invalid while the busy flag is set. And implementing the busy flag is relatively easy, by using a pull up resistor on the D7 pin.