Low-Power, 8-Channel, 24-Bit Analog front-end for biopotential measurements

The  TI ADS1298R could be perfect for that EKG project you dreamed of. It has a 8 analog to digital converters with programmable gain amplifiers, an internal reference, and a clock source.

The ADS1294/6/8/4R/6R/8R incorporate all of the features that are commonly required in medical electrocardiogram (ECG) and electroencephalogram (EEG) applications.

FEATURES

  • Eight Low-Noise PGAs and Eight High-Resolution ADCs (ADS1298, ADS1298R)
  • Data Rate: 250SPS to 32kSPS
  • Programmable Gain: 1, 2, 3, 4, 6, 8, or 12
  • Unipolar or Bipolar Supplies: AVDD = 2.7V to 5.25V, DVDD = 1.65V to 3.6V
  • Built-In Right Leg Drive Amplifier, Lead-Off Detection, WCT, PACE Detection, Test Signals
  • Integrated Respiration Impedance Measurement (ADS1294R/6R/8R only)
  • SPI™-Compatible Serial Interface
  • TQFP-64

This is a massive analog chip. Thanks McZ!



PyMite: Python-on-a-chip

Python-on-a-Chip (p14p) is a project to develop a reduced Python virtual machine (codenamed PyMite) that runs a significant subset of the Python language on microcontrollers without an OS. The other parts of p14p are the device drivers, high-level libraries and other tools. They’ve released ports for the Microchip PIC/24dcPIC, Teensy 2.0, Arduino Mega and others. Here is their PyCon 2011 Lightning Talk slide presentation.

Some features of PyMite include a memory requirement of roughly 55 KB program memory, supports integers, floats, tuples, lists, dicts, functions, modules, classes, generators, decorators and closures, supports 25 of 29 keywords and 89 of 112 bytecodes from Python 2.6 and is licensed under the GNU GPL ver. 2. However, it lacks a built-in compiler, and does not include any of Python’s libraries. If you know C, Python and how to work with microcontrollers, it might be worth checking out.

App note: Intro to digital communications systems

Digital modulation techniques are seeing increasing use worldwide. In the US, the FCC is actually mandating narrowband digital mobile radio (DMR) for certain Land Mobile Radio (LMR) users as explained in this Digital Mobile Radio Association white paper. Datasheets for various chips increasingly made reference to acronyms like GMSK, FSK and others.

Agilent has published this comprehensive 48 page application note, Digital Modulation in Communications Systems – An Introduction, which provides a clear, authoritative explanation of digital modulation. Definitely worth the read!

App notes: RGB LED driver reference design

An introduction to RGB LED driver reference design for a low-power projector.

This application note is an RGB LED driver reference design for a low-power projector. The design features a single MAX16821 HB LED driver to drive the RGB LEDs one at a time. This approach reduces the components needed, resulting in an efficient, small, and economical design. Board layout and test results are shown.

Thanks rsdio!

Notes on the SMBus

The System Management Bus (SMBus) was defined by Intel® Corporation in 1995. It was originally used in personal computers and servers for low-speed system management communications. It is more or less a derivative of the I2C bus. The current SMBus specification document is Version 2.

Today the SMBus is being used in a small but growing number of embedded devices and sensors, and its always good to be familiar with obscure protocols.

Examples of contemporary use in embedded systems are to communicate with user flash memory in Altera’s MAX II devices, and to communicate with TAOS Ambient Light Sensors.

Here’s an application note from TAOS called the Bit Banger’s Guide to the SMBus.

Radio spectrum dashboard


The FCC has a unique and authoritative reference known as the Radio Spectrum Dashboard. It provides a public means of reviewing how spectrum bands are allocated and for what uses, and who holds licenses and in what areas.

This version provides basic, plain language information about frequencies generally deemed appropriate for mobile broadband (225 MHz to 3700 MHz.) In addition, Spectrum Dashboard contains more detailed information, mapping, and research capabilities for the bands where broadband service is either already available, or potentially could be provided.

If you’re interested in who uses those relatively unknown radio bands, and particularly if you want to conduct research using a software defined radio (SDR), this resource is invaluable.

In addition to the webpage inquiry services, the FCC announced two new APIs on the FCC developer page. These APIs leverage data from the Spectrum Dashboard and provide the developer community with direct access to these assets.

TOOL: Aoyue 968 3-in-1 rework station

Our favorite tools have a new home on the wiki. Each week we’ll muse a bit about one of them. Have your own tool review? We’ll post that too!

Our trusty Aoyue 968 was the first real electronics tool we bought. It’s a three-in-one rework station with a soldering iron, hot air rework tool, and solder fume extractor, for around $100. Ian looked at it inside and out in a Hack a Day article a few years ago.

The adjustable temperature iron is a huge step up from the cheap fixed-temperature tools we used in the past. It takes standard Hakko tips, but we just replaced the first one recently after more than 5 years of heavy use. The first part to actually break was the handle of the soldering iron, probably from rough use while desoldering. A replacement iron assembly, with cable, tip, and everything, was only $14. The replacement iron came with a chisel bit we didn’t like, so the original tip went on the new handle.

Fume extraction won’t appeal to everyone, but we sure like it. A tube near the tip of the iron sucks up flux fumes and blows them out the rework tool. It makes soldering a lot more pleasant, though the pump can be a bit loud.

Hot air is a must for surface mount prototyping. The hot air tool worked great for about 5 years, but recently it seems to have a short in the temperature sensor wire. When the cable bends the wrong way, the temperature display jumps to maximum and it goes into an auto-shutdown mode. We bought the Aoyue 852 to replace the hot air part, but we wouldn’t hesitate to buy another 968 because it provided years of great service for a ridiculously low price.

We love this tool and highly recommend it to anyone.

The Aoyue 968 is pictured with the OptiVisor magnifier available at Adafruit. Buy it, it will make your life better.

There’s more tools too.

Arduino used for ThinkPad password recovery

The Seeeduino is being resold as a ThinkPad password recovery tool:

the only Affordable Fully Assembled, Programmed and Tested unlimited use USB based ThinkPad Supervisor Password Recovery or Clear Tools in the world.

Joe’s KeyMaker KMX1 can Recover or Clear Supervisor Password from all current ThinkPad models with the exception of the SL400 and SL500 series, it can do this even if TPM security has been enabled

This came through the contact form with a negative comment. We posted it because it’s interesting to see the Arduino used in a niche product, especially in a gray-market product that otherwise might not be possible. This is closed source, but it seems like a similar open source firmware could be loaded onto any Arduino.

Kicad tutorial

Kicad is an open source (GPL) software for the creation of electronic schematic diagrams and printed circuit board artwork, and consists of a set of four softwares and a project manager: Eeschema (schematic entry), Pcbnew (board editor), Gerbview (GERBER viewer), Cvpcb (the footprint selector for components used in the circuit design) and the Kicad project manager. The Linux and Windows versions can be downloaded here.

Brian from teho Labs wrote to inform us of a Kicad tutorial written by the lab.

Thanks Brian! Via the contact form.

Arduino logic analyzer with Logic Sniffer client

gillham wrote a logic analyzer firmware for the Arduino that works with on the Logic Sniffer client:

Reading through the SUMP docs the protocol looked simple enough that I thought “Why not try implementing this on the Arduino?” and set about it. After getting my code to respond appropriately and kind of working with the client I went about trying to get some accuracy. That is when I ordered an OLS of my own.

Ultimately I was able to get some fairly precise sampling on the Arduino by watching a debug pin with the OLS and eventually I had a really basic working SUMP compatible logic analyzer!

Via the forum.

Get the Logic Sniffer for $50, with free worldwide shipping.

Arduino motion detection camera

Inspired by the intervalometer project at the Honey Jar, Dan Bridges produced a motion activation control to use with his Canon SLR camera. It uses an Arduino, a PIR sensor and two 4N35 optocouplers and this source code. He next plans to add a potentiometer and LCD screen to allow for custom time intervals on the go.

CAN sniffing for steering wheel button presses

Newer protocols are always fun to explore, such as the automotive CAN bus. Here’s a project by wire2wire which sniffs the CAN signals from steering wheel controls and converts them to a serial output. The main components are a PIC16F876, MCP2515 and MCP2551.

The code and all docs are available in a zip file. Current firmware images include:VW MKV GTI “infotainment bus” 100kbs, raw bus dump (sniffer/snoop), and basic steering wheel button decode. Firmware also has TTL outputs for each of the buttons on the steering wheel. These outputs can be directly interfaced to other devices / inputs without using a PC or another micro. For example you can set up the “phone” button to turn on a light when pressed.

Via Hack a Day.

PROTOTYPE: xQFP protoboard with SOIC, SSOP, 0805 footprints

Today we’re super excited to announce a new QFP prototype board for SMD parts, the newest addition to our Dangerous Protoboard collection. This giant protoboard has a xQFP breakout footprint, along with a score of other pads for SMD parts. Great for getting started with a new microcontroller.

Dangerous Protoboard: xQFP. Prototype board for working with xQFP chips and SMD parts. It has footprints for:

  • 32-80pin xQFP packages, each pin brought to a header
  • SOIC(W) chips from .150″ to .3″ (max 32 pins)
  • xSSOP chips (max 32 pins)
  • Buttons with pull-up resistor input area (2x)
  • LEDs with resistor output area (8x)
  • SMD or through hole crystal with capacitors
  • SOT-23-3/5/6 (6x)
  • 0805 R and C (8x, plus extras near IC footprints)
  • DO-323 (8x)
  • 24×10 pin through-hole prototype area
  • Power bus routed near all components
  • Silk labels on top and bottom
  • Open source (CC-BY-SA)
  • Design files

Currently available in 0.50mm, 0.65mm, and 0.80mm for $10.

Don’t know your size? See choosing a prototype board.

We’re super proud of this board, it’s something we use all the time to develop our own projects. What makes Dangerous Protoboards unique?

  • Developed and constantly refined during real-world use prototyping our projects
  • An open source licensed protoboard collection (CC-BY-SA), maybe the only one
  • Each sale supports our efforts to buy a USB VID

We’re giving away a couple of these to celebrate the launch, just ask for one in the comments.