A Workspace for “Engineering Magic”

Brandsma_workspace2

Photo 1—Brandsma describes his workspace as his “little corner where the engineering magic happens.”

Sjoerd Brandsma, an R&D manager at CycloMedia, enjoys designing with cameras, GPS receivers, and transceivers. His creates his projects in a small workspace in Kerkwijk, The Netherlands (see Photo 1). He also designs in his garage, where he uses a mill and a lathe for some small and medium metal work (see Photo 2).

Brandsma_lathe_mill

Photo 2—Brandsma uses this Weiler lathe for metal work.

The Weiler lathe has served me and the previous owners for many years, but is still healthy and precise. The black and red mill does an acceptable job and is still on my list to be converted to a computer numerical control (CNC) machine.

Brandsma described some of his projects.

Brandsma_cool_projects

Photo 3—Some of Brandsma’s projects include an mbed-based camera project (left), a camera with an 8-bit parallel databus interface (center), and an MP3 player that uses a decoder chip that is connected to an mbed module (right).

I built a COMedia C328 UART camera with a 100° lens placed on a 360° servomotor (see Photo 3, left).  Both are connected to an mbed module. When the system starts, the camera takes a full-circle picture every 90°. The four images are stored on an SD card and can be stitched into a panoramic image. I built this project for the NXP mbed design challenge 2010 but never finished the project because the initial idea involved doing some stitching on the mbed module itself. This seemed to be a bit too complicated due to memory limitations.

I built this project built around a 16-MB framebuffer for the Aptina MT9D131 camera (see Photo 3, center). This camera has an 8-bit parallel databus interface that operates on 6 to 80 MHz. This is way too fast for most microcontrollers (e.g., Arduino, Atmel AVR, Microchip Technology PIC, etc.). With this framebuffer, it’s possible to capture still images and store/process the image data at a later point.

This project involves an MP3 player that uses a VLSI VS1053 decoder chip that is connected to an mbed module (see Photo 3, right). The great thing about the mbed platform is that there’s plenty of library code available. This is also the case for the VS1053. With that, it’s a piece of cake to build your own MP3 player. The green button is a Skip button. But beware! If you press that button it will play a song you don’t like and you cannot skip that song.

He continued by describing his test equipment.

Brandma_test_equipment

Photo 4—Brandsma’s test equipment collection includes a Tektronix TDS220 oscilloscope (top), a Total Phase Beagle protocol analyzer (second from top), a Seeed Technology Open Workbench Logic Sniffer (second from bottom), and a Cypress Semiconductor CY7C68013A USB microcontroller (bottom).

Most of the time, I’ll use my good old Tektronix TDS220 oscilloscope. It still works fine for the basic stuff I’m doing (see Photo 4, top). The Total Phase Beagle I2C/SPI protocol analyzer Beagle/SPI is a great tool to monitor and analyze I2C/SPI traffic (see Photo 4, second from top).

The red PCB is a Seeed Technology 16-channel Open Workbench Logic Sniffer (see Photo 4, second from bottom). This is actually a really cool low-budget open-source USB logic analyzer that’s quite handy once in a while when I need to analyze some data bus issues.

The board on the bottom is a Cypress CY7C68013A USB microcontroller high-speed USB peripheral controller that can be used as an eight-channel logic analyzer or as any other high-speed data-capture device (see Photo 4, bottom). It’s still on my “to-do” list to connect it to the Aptina MT9D131 camera and do some video streaming.

Brandsma believes that “books tell a lot about a person.” Photo 5 shows some books he uses when designing and or programming his projects.

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Photo 5—A few of Brandsma’s “go-to” books are shown.

The technical difficulty of the books differs a lot. Electronica echt niet moeilijk (Electronics Made Easy) is an entry-level book that helped me understand the basics of electronics. On the other hand, the books about operating systems and the C++ programming language are certainly of a different level.

An article about Brandsma’s Sun Chaser GPS Reference Station is scheduled to appear in Circuit Cellar’s June issue.

Dynamic Efficiency Microcontrollers

STMicroThe STM32F401 Dynamic Efficiency microcontrollers extend battery life and support innovative new features in mobile phones, tablets, and smart watches. They help manage MEMS sensors in smart-connected devices and are well suited for Internet-of-Things (IoT) applications and fieldbus-powered industrial equipment.

The STM32F401 microcontrollers include an ART accelerator, a prefetch queue, and a branch cache. This enables zero-wait-state execution from flash, which boosts performance to 105 DMIPS (285 CoreMark) at 84 MHz. The microcontrollers’ 90-nm process technology boosts performance and reduces dynamic power. Its dynamic voltage scaling optimizes the operating voltage to meet performance demands and minimize leakage.

The STM32F401 microcontrollers integrate up to 512 KB of flash and 96 KB SRAM in a 3.06-mm × 3.06-mm chip-scale package and feature a 9-µA at 1.8 V Stop mode current. The devices’ peripherals include three 1-Mbps I2C ports, three USARTs, four SPI ports, two full-duplex I2S audio interfaces, a USB 2.0 OTG full-speed interface, an SDIO interface, 12-bit 2.4-MSPS 16-channel ADC, and up to 10 timers.

Pricing for the STM32F401 microcontrollers starts at $2.88 in 10,000-unit quantities.

STMicroelectronics
www.st.com

Emerging Memory Technologies

Some experts predict it will be at least another decade before new memory technologies offer the low prices and wide availability to compete with NAND-based flash memory. Nonetheless, it’s worthwhile to look at potential NAND-flash successors, including phase-change RAM (PRAM), resistive RAM (ReRAM), and magnetoresistive RAM (MRAM).

In December’s Circuit Cellar magazine, now available online, Faiz Rahman describes and compares the newest memory technologies available for embedded systems.

“I cover only those devices that are now commercially available, but bear in mind that many other technologies are being hotly pursued in academic and corporate research labs worldwide,” says Rahman, an Ohio University visiting professor who received his PhD in Electrical Engineering from Imperial College, London.

For example, last summer MIT Technology Review reported on a startup company’s testing of crossbar memory. The new technology, according to an August 14, 2013, article written by Tom Simonite, can store data 40 times as densely as the most compact memory available and is faster and more energy-efficient.

Here are the commercially-available technologies Rahman considers and some of his insights. (For the full article with more details, including an update on manufacturers of the latest memory devices, check out the December issue.)

PHASE-CHANGE RAM
One of the most interesting memory types to emerge in recent years is one that stores data as order or disorder in small islands of a special material. The structural transition

The structure of phase-change RAM cells in reset and set states is shown.

The structure of phase-change RAM cells in reset and set states is shown.

between ordered and disordered phases is driven by controlled heating of the material island…

There have been several recent advances in phase-change RAM (PRAM) technology. Perhaps the most remarkable is the ability to control the cell-heating current precisely enough to create several intermediate cell-resistance values. This immediately increases the memory capacity as each cell can be made to store more than one bit. For example, if eight resistance values can be created and distinguished, then the cell can be used to store three bits, thus tripling the memory capacity. This is now a routinely used technique implemented with PRAM devices.

MAGNETORESISTIVE RAM
We have all wished for a computer with no start-up delay that could be ready to use almost as soon as it was powered up. Such a computer will need to use an inexpensive

A spin-torque magnetoresistive RAM cell’s structure includes a free layer, a tunnel barrier, and a fixed layer.

A spin-torque magnetoresistive RAM cell’s structure includes a free layer, a tunnel barrier, and a fixed layer.

but fast nonvolatile memory. This combination is difficult to come by, but proponents of magnetoresistive RAM (MRAM) think boot times could soon become outdated as this new memory becomes a mature product….

MRAM’s nonvolatility alone will not make it a potential game-changing technology. Its high-access speed is what makes it special. Unlike other nonvolatile memory (e.g., EEPROMs and flash), MRAM boasts typical access speeds of 35 ns and potentially as short as 4 ns, with further developments. This combined with MRAM’s extremely high endurance and data retention periods of more than 20 years even makes the technology suitable for use as CPU cache memories, which is a very demanding application.

One further advantage of MRAM is that its basic architecture—where the access transistor can be formed directly on top of the magnetic tunnel junction (MTJ)—enables very dense integration, greatly reducing the cost of storage per bit and making MRAM well suited for use in solid-state disks.

FERROELECTRIC RAM
In many ways, DRAM is an example of an ideal memory, if it weren’t for its volatility… The problem is that the charge stored in a DRAM cell tends to disappear due to self-discharge

A ferroelectric RAM cell’s organizational structure is shown.

A ferroelectric RAM cell’s organizational structure is shown.

after only a few milliseconds. This means that all DRAM chips have to be periodically read and every cell’s state must be restored every few milliseconds. The requirement for periodic “refresh” operations increases the power consumption of DRAM banks, in addition to endangering data integrity in the case of even short power supply dips.

Within this backdrop, ferroelectric RAM (FRAM) became a potential game changer when it was introduced in the early 1990s…The permanence of induced electrical polarization in ferroelectric capacitors endows FRAMs with their nonvolatility. To write a particular bit, a FRAM’s cell capacitor is briefly charged in one direction to polarize the ferroelectric material between its plates. The capacitor voltage can then be removed and the bit state will be retained in the directional sense of the dielectric material’s polarization. No charges may leak away, and the polarization can be maintained for many years making FRAM, in a sense, a nonvolatile analog of DRAM….

A big advantage of using FRAM in microcontrollers is that just one memory can be used for program, data, and information storage instead of having to use separate flash, SRAM, and EEPROM blocks, which has been the trend so far.

RESISTIVE RAM
Phase-change memory uses programmed heat-generating current pulses to affect memory cell resistance changes. However, resistive RAM (ReRAM)—a still developing memory breed—uses voltage pulses to make resistance changes. This memory technology

A typical resistive RAM cell’s structure is shown.

A typical resistive RAM cell’s structure is shown.

utilizes materials and structures where suitable voltages can alter memory cells’ resistive states so they can store one or more data bits, similar to PRAM.

There are strong hints that ReRAM is capable of very fast switching with symmetric read and write times of less than 10 ns. This comes with a remarkably low power consumption, which should make this technology ideal for many applications.

As if these attributes were not enough, ReRAM cells are very small and can be placed extremely close together, which results in high-density memory fabrics.

Rahman’s article also introduces manufacturers offering products with the latest memory technologies, but he declares no single memory device the best. Despite manufacturers extolling their particular products, those that succeed will need to be available in high volume and at low cost, he says. They also must offer high-storage densities, he says, a bar most new memory technologies struggle to reach.

Ace Monster Toys – 3D Printing, DIY Book Scanners and “Dirty Shops”

Ace Monster Toys is a Hackerspace in the East San Francisco Bay Area dedicated to education, hacking, and maker culture since September 2010. They are a membership based group with regular free open-to-the-public classes and events. They are open to anyone and non-members are welcome.

Location 6050 Lowell Street, Oakland, CA
Members 55
Website AceMonsterToys.org

Ace Monster Toys Hackerspace

Here’s what Ace Monster Toys member David has to say about his group:
Tell us about your meeting space!

Our space is 1600 sq ft, divided among three rooms, one upstairs and two downstairs. The upstairs is the “less dirty” area, with desks for working on projects, space for meetings and classes, electronics work area, and 3D printers. Downstairs is the “dirty shop,” in which one room is mostly woodworking tools with a large CNC mill and the other room contains the laser cutter and some storage. We have many shelves where members can put their projects in boxes as well as a few small storage lockers, both upstairs and downstairs.

What tools do you have in your space? (Soldering stations? Oscilloscopes? 3-D printers?)

Everything and the kitchen sink it seems like! Downstairs is a giant 80W laser cutter, a giant CNC router table (both capable of taking full sheets of plywood or other woods), a mini desktop CNC router, several different woodworking tools (bandsaw, chop saw, radial arm saw, table saw, router table, jointer, wood lathe, various power hand tools), a metal bandsaw, a micro metal lathe, a drill press, and a Zcorp powder based 3D printer. Upstairs we have several textile machines (serger, sewing machines), oscilloscopes, logic analyzers, soldering stations, three plastic FDM type 3D printers, a DIY book scanner, a large format inkjet printer, and a roomba or three.

Are there any tools your group really wants or needs?

A more reliable 3D printer would be pretty nice. Also a CNC mill capable of working metal would be really cool and would allow us to fabricate metal parts. A decent tabletop or larger metal lathe would expand our fabrication abilities. For textiles: Supplies for conductive sewing projects/classes… lilipad everything, conductive fabric, thread, battery packs, batteries. Not just for the classes themselves but also for prototyping projects.

Does your group work with embedded tech (Arduino, Raspberry Pi, embedded security, MCU-based designs, etc.)?

Yes! We have lots of Arduino and Raspberry Pi fans, but of course we have people who work with other microcontrollers as well (ARM based mostly I’d say).

Can you tell us about some of your group’s recent tech projects?

One group project we built was a laser shooting gallery — targets had light sensors and were attached to servo motors, would pop up, and then you had to shoot them with a laser pointer gun. There were sound effects and a score display. You can read more details about it here: wiki.acemonstertoys.org/Shooting_Gallery and there are some videos here: popmechnow.com/radioshack (on the left side) One of our members has been working on using a small desktop CNC router to make custom circuit boards. It uses a neat hack to probe the level of the bed to create more accurate cuts. The results have been pretty good. There’s lots of details about this project here: wiki.acemonstertoys.org/Milling_Circuit_Boards

Another cool and not too complex project is 3D scanning our members and then printing out the models on our 3D printer. We use an inexpensive xbox kinect to do the scanning, along with the free version of the software Skanect, and then we load that model into our Makergear Mosaic 3D printer and spit them out. Here’s a picture of two of our members in plastic model format:

3D Scans of Ace Monster Toys' members

What’s the craziest project your group or group members have completed?

Craziest? It’s hard to say, lots of crazy stuff comes out of this place. One impressive project is our Book Scanner, made from plywood, random hardware store nuts and bolts, and a bike brake cable which triggers the shutters on two cameras to photograph two pages at once. It’s gotten a lot of press, the inventor even gave a TED Talk about it. He made his own website for it, you can find more details here: www.diybookscanner.org

Do you have any events or initiatives you’d like to tell us about? Where can we learn more about it?

Our current biggest initiative is moving to a bigger space. We would like to double our square footage and offer more facilities & capabilities including accessibility. For events which are going on, many of them weekly, check out the calendar on our website or on meetup.acemonstertoys.org.

What would you like to say to fellow hackers out there?

“Collaboration and connection has done more to further my knowledge and to produce better, more creative art and projects and innovative ideas than any other factor. Be fearless. Ask questions, try it. Don’t be afraid to cut, or solder or try even when it seems hard or complicated. Everybody starts somewhere.” ~ Crafty Rachel

Check out Ace Monster Toys’ pages on Instructables and Facebook!

You can read all about their projects on their wiki page.

Show us your hackerspace! Tell us about your group! Where does your group design, hack, create, program, debug, and innovate? Do you work in a 20′ × 20′ space in an old warehouse? Do you share a small space in a university lab? Do you meet a local coffee shop or bar? What sort of electronics projects do you work on? Submit your hackerspace and we might feature you on our website!