Blog posts by Bill Marshall

Like my colleague at RS, I had a chance to play with one of the first Raspberry Pi boards in the UK. My remit was to see how easy it is for someone unfamiliar with Linux to get a system working from scratch.

The Fedora Remix seems to be the recommended option on the Raspberry Pi site. If you don't know much about installing Linux distros, then this is the route to take because a special image installer program is provided which runs under Windows. Other, possibly better distros are available, but are more awkward to transfer to the SD memory card. It is not just a question of copying files across. So step 1 is to download the Fedora Remix (all 500MB of it) followed by the installer program. You need to unzip the installer into a suitable directory, making sure the directory name contains no spaces. Running the program puts up a simple window inviting you to browse to the location of the downloaded image file, and to specify the destination drive. The program detects any Flash memories present (SD card, memory stick, etc) and you just need to select the SD card, assuming it is plugged into a suitable reader. The installer does not present your C: drive as a choice, thus preventing you from trashing your system. As I said, the installer does not copy files: it overwrites the destination memory with an image wiping out everything already there. This image transfer proceeded smoothly in my case and the SD card was then plugg… Read more

A competition has been announced with a $10m prize for the first working medical tricorder. If you claim to be an engineer and don't know what I'm talking about, then may I suggest locking yourself in a room with a DVD box set of the original Star Trek TV series. Don't come out until you can describe in detail the operation of Inertial Dampers and Transporter Pattern Buffers. You may now justifiably call yourself an engineer and embark upon this $10m quest. Seriously, what did inspire my generation of school kids to take up electronics? It certainly wasn't school: UK grammar schools in the 1960's didn't teach it. Technical High schools did and turned out students with A-levels in Engineering which provided exemptions from some subjects in the first year at university! Naturally these schools were all shut down because they were deemed too expensive. When the IT revolution began in the 1980’s UK schools were ill-equipped to meet the challenge.

Read more

I’ve noticed an interesting trend recently. Forgive my lack of awareness if this has all been said before, but here it is: microcontroller chip manufacturers are making/supporting some very cheap development kits nowadays. Not only that, but the through-hole DIP package is making a comeback, most notably with the NXP LPC1100 Cortex-M0 MCU in a 28-pin DIP and other 'developer-friendly' forms.

It must be down to the new way of working in product development which, at least in it’s early stages, may involve Internet social networking sites and the ‘Cloud’. This change in emphasis may be coming about because the big consumer electronics companies are either going out of business, dumping their R & D and training departments so sealing their fate, or outsourcing product development to universities and SMEs. With a few well-known exceptions most university departments can’t afford to buy expensive development kit every time a new chip appears and neither can a one-man-band startup company. Some of the more powerful 16- and 32-bit MCUs of late have required the purchase of development kits costing hundreds or even thousands of dollars, pounds or Euros. Not to mention the software tools needed in non-trial form often costing a lot more than the hardware. Read more

Texas Instruments have recently launched a new range of ARM-core microcontrollers called Hercules. They contain redundant circuits to detect and deal with faults when used in safety-critical applications. Specifically, two Cortex R4F cores run a common program in lockstep and a comparator unit makes sure they produce the same outputs.

Computers are unreliable, prone to making random mistakes. Anybody using a PC for standard office work will testify to that: mysterious error messages, program ‘crashes’ and even the dreaded ‘blue screen of death’. For many years most computer installations’ MTBF (Mean Time Between Failures) could be measured in hours. Most of the problems were down to the hardware. Imagine a computer built with thousands of thermionic valves (tubes): to keep it going for a whole day involved increasing the power supply voltage first thing in the morning to stress weak valves into failure. With these replaced the machine would work without problems for the next 24 hours – usually. Even later very high performance computers built from early integrated circuits were not much better. It’s a good job these room-sized power-hungry monsters wouldn’t fit into a train cab or an airplane! The Apollo Guidance Computer is probably the first example of a mobile computer on which lives depended. Fortunately it was monitored by a human brain. Just as well: it got overloaded on the first moo… Read more