About Circuit Cellar Staff

Circuit Cellar's editorial team comprises professional engineers, technical editors, and digital media specialists. You can reach the Editorial Department at editorial@circuitcellar.com, @circuitcellar, and facebook.com/circuitcellar

Arduino USB Host Shield

The Arduino USB Host Shield allows you to connect a USB device to your Arduino board. The Arduino USB Host Shield is based on the MAX3421E, which is a USB peripheral/host controller containing the digital logic and analog circuitry necessary to implement a full-speed USB peripheral or a full-/low-speed host compliant to USB specification rev 2.0.ArduinoHostshield

The shield is TinkerKit compatible, which means you can quickly create projects by plugging TinkerKit modules onto the board. The following device classes are supported by the shield:

  • HID devices: keyboards, mice, joysticks, etc.
  • Game controllers: Sony PS3, Nintendo Wii, Xbox360
  • USB to serial converters: FTDI, PL-2303, ACM, as well as certain cell phones and GPS receivers
  • ADK-capable Android phones and tables
  • Digital cameras: Canon EOS, Powershot, Nikon DSLRs and P&S, as well as generic PTP
  • Mass storage devices: USB sticks, memory card readers, external hard drives, etc.
  • Bluetooth dongles

For information on using the shield with the Android OS, refer to Google’s ADK documentation. Arduino communicates with the MAX3421E using the SPI bus (through the ICSP header). This is on digital pins 10, 11, 12, and 13 on the Uno and pins 10, 50, 51, and 52 on the Mega. On both boards, pin 10 is used to select the MAX3421E.

[Source: Arduino website via Elektor]

A Rat’s Nest-Less Workspace: Clean with Plenty of Screens

Two sorts of things we love to see in an electronics workspace: cleanliness and multiple monitors! San Antonio, TX-based Jorge Amodio’s L-shaped modular desk is great setup that gives him easy access to his projects, test equipment, and computers. The wires to all of his equipment are intelligently placed behind and below the workspace. Hence, no rat’s nest of wires! He doesn’t need to work on top of cords and peripherals like, well, a few of us do here in our office. We like how he “sectioned” his space to provide maximum multitasking capability. The setup enables him to move easily from doing R&D work to emailing to grabbing his iPhone without any more effort than a slide of his chair. Very nice.

Jorge Amodio’s workspace (Source: J. Amodio)

Submitted by Jorge Amodio, independent consultant and principal engineer (Serious Integrated, Inc.), San Antonio, TX, USA

“For the past few years I’ve been working on R&D of intelligent graphic/touch display modules for HMI (Human Machine Interface) and control panels, with embedded networking for ‘Internet of Things’ applications.” – Jorge Amodio

Jorge perform R&D with handy test equipment an arm’s length away (Source: J. Amodio)

A closer look at Jorge’s project space (Source: J. Amodio)

Jorge has easy access to his other monitors and iPhone (Source: J. Amodio)

Do you want to share images of your workspace, hackspace, or “circuit cellar”? Send your images and space info to editor at circuitcellar dotcom.

New DSP “Lab-in-a-Box” for ARM-Based Audio Systems

Cambridge, UK-based, ARM and its partners will start shipping a DSP “Lab-in-a-Box” (LiB) to universities worldwide to help boost practical skills development and the creation of new ARM-based audio systems. This will include products such as high-definition home media and voice-controlled home automation systems. The LiB kits contain ARM Cortex-M4-based microcontroller boards by STMicroelectronics and audio cards from Wolfson Microelectronics and Farnell element14.ARMDSPLiBWeb

As the centerpiece of the ARM University Program, LiB packages offer ARM-based technology and high-quality teaching and training materials that support electronics and computer engineering courses. DSP courses have traditionally used software simulation packages, or hands-on labs using relatively expensive development kits costing around $300 per student. By comparison, this new DSP LiB will cost around $50 and will allow students to practice theory with advanced hardware sourced from widely-available products.

“Our Lab-in-a-Box offerings are proving hugely popular in universities because of the low-cost access to state-of-the-art technology,” said Khaled Benkrid, manager of the Worldwide University Program, ARM. “The DSP kits, powered by ARM Cortex-M4-based processors, enable high performance yet energy-efficient digital signal processing at a very affordable price. We expect to see them being used by students to create commercially-viable audio applications and it’s another great example of our partnership supporting engineers in training and beyond.”

The DSP LiB will begin shipping to universities in July 2014. It is the latest in a series of initiatives led by ARM which span multiple academic topics including embedded systems design, programming and SoC design. The DSP kits will also be offered to developers outside academia at a later date.

[via audioXpress.com]

Test Under Real Conditions (EE Tip #137)

The world’s best engineers have one thing in common: they’re always learning from their mistakes. We asked Niagara College professor and long-time contributor Mark Csele about his biggest engineering-related mistake. He responded with the following interesting insight about testing under real conditions.

Mark Csele's complete portable accelerometer design, which he presented in Circuit Cellar 266.  with the serial download adapter. The adapter is installed only when downloading data to a PC and mates with an eight pin connector on the PCB. The rear of the unit features three powerful rare-earth magnets that enable it to be attached to a vehicle.

Mark Csele’s complete portable accelerometer design, which he presented in Circuit Cellar 266. with the serial download adapter. The adapter is installed only when downloading data to a PC and mates with an eight pin connector on the PCB. The rear of the unit features three powerful
rare-earth magnets that enable it to be attached to a vehicle.

Trusting simulation (or, if you prefer, lack of testing under real conditions). I wrote the firmware for a large three-phase synchronous control system. The code performed amazingly well in the lab, and no matter what stimulus was applied, it always produced correct results. When put into operation in the field (at a very large industrial installation), it failed every 20 minutes or so, producing a massive (and dangerous) step-voltage output! I received a call from a panicked engineer on-site, and after an hour of diagnosis, I asked for a screenshot of the actual power line (which was said to be “noisy,” but we knew this ahead of time) only to be shocked at how noisy. Massive glitches appeared on the line many times larger than the AC peak and crossing zero several times, causing no end of problems. Many hours later (the middle of the morning), the software was fixed with a new algorithm that compensated for such “issues.” This was an incredibly humbling experience: I wasn’t nearly as smart as I had thought, and I really missed the boat on testing. I tested the system under what I thought were realistic conditions, whereas I really should have spent time investigating what the target grid really looked like.—Mark Csele, CC25 (anniversary issue)

High Dynamic-Range Audio Processor

STMicroelectronics recently introduced a new digital audio processor with greater than 100-dB SNR and Dynamic Range. The device can process most digital input formats including 6.1/7.1 channel and 192-kHz, 24-bit DVD audio and DSD/SACD. When configured in a 5.1 application, its additional two channels can be used to supply audio line-out or headphone drive.

Source: STMicroelectronics

Source: STMicroelectronics

The STA311B is a single chip solution for digital audio processing and control in multichannel applications, providing FFXTM (Full Flexible Amplification) compatible outputs. Together with a FFXTM power amplifier it can provide high-quality, high-efficiency, all-digital amplification.

The chip accepts digitized audio input information in either I2S (left or right justified), LSB or MSB first, with word lengths of 16, 18, 20 and 24 bits. Its pop-noise removal feature does not discriminate against the music genre but instead prevents any audible transients or pops finding their way through to the power amp where they may damage the speakers. Device control is via an I2C interface. The STA311B embeds eight audio-processing channels with up to 10 independent user-selectable bi-quadratic filters per channel to allow easy implementation of tone and music genre equalization templates. It is capable of input and output mixing with multi-band dynamic range compression. The chip also has input sampling frequency auto-detection, input/output RMS metering and employs pulse-width modulated output channels.

The STA311B is supplied in an 8.0 × 8.0 × 0.9 mm VFQFPN package.

[via Elektor]