Old School Side Project: I wanted to create a universal BCD controlled nixie display driver that could be made into a simple module for any application. Here for demonstration I have breadboarded an automatic counting circuit with a 555 wild clock triggering a BCD output up/down counter to act as a driver for the separate high voltage transistor control/switching board and nixie display, with complete low voltage regulated and high voltage supplies. All vintage parts too. Enjoy!
The 8088 has a hardware multiplier, but it’s quite slow:
MUL with byte arguments: 69 cycles plus 1 for each set bit in AL plus 1 if the high byte of the result is 0
MUL with word arguments: 123 cycles plus 1 for each set bit in AX plus 1 if the high word of the result is 0
Signed multiplies are even slower (taking at least 80 cycles for a byte, 134 cycles for a word), and depend on the number of set bits in the absolute value of the accumulator, the signs of the operands and whether or not the explicit operand is -0×80 (-0×8000 for word multiplies). I also measured some word IMULs apparently taking a half-integer number of cycles to run, suggesting that there’s either some very weird behavior going on with the 8088′s multiplier or that there’s a bug in my timing program (possibly both).
Can we beat the 8088′s hardware multiplier with a software routine?
For added peace of mind now you can verify your PCB data prior to placing your order. PCB Visualizer is an automatic tool for data input and manufacturability analysis. Clear graphic presentation pinpoints any issues found. You can then fix them up front, helping to avoid delays to your time-critical deliveries. Upload your Extended Gerber (RS274X) or CadSoft EAGLE V6 files and let us surprise you.
My last business card was too expensive to give out, so I designed this one using a Texas Instruments MSP430. Combined with the chip’s Pin Oscillator hardware, and TI’s Capsense Library, it wasn’t too difficult enabling capacitive touch. The great thing is that in software I can have it go into a low power mode and check the button every second or so. When it senses a a touch, it checks more frequently and only leaves low power mode to toggle an LED. I guess when you’re driving LED’s, low power sleep isn’t going to help much, but there are times when no LED’s are lit, even in the middle of a display routine.
After 38 years, the BBC’s CeeFax teletext service shut down on 23:30 BST, October 23rd. The service, conceived of by BBC engineers in the early 1970′s, was originally designed to allow textual data to be transmitted to viewers alongside video data. The service worked by inserting non-video data into the blanking interval of a standard video signal (PAL in this case), similar to closed captioning here in the US.
The data transmitted by CeeFax ranged from sports scores to crime updates to programs for the BBC Micro. I can’t say I have any first hand experience of using CeeFax, but judging by the response on Twitter to this tweet by Joel Morris, and this tribute article, it seems it was many things to many people and will be missed — a neat hack that enriched a lot of people’s lives. More from BBC News:
Olympic champion Dame Mary Peters will turn off the last analogue TV signal in Northern Ireland at 23.30 BST. A series of graphics on Ceefax’s front page will mark its 38 years on the BBC.
The Plain English Campaign announced a lifetime achievement award for Ceefax’s “clarity” and use of “everyday words”.
And ex-Prime Minister Sir John Major said Ceefax would be “much missed”.
Sir John, who has previously revealed that he regularly checked Ceefax pages between Downing Street meetings to keep up to date with cricket scores, said: “Ceefax will be much missed. At moments of high pressure – with little time for detailed examination of the news – Ceefax headlines offered an instant window on the world.
Ceefax was launched on 23 September 1974 to give BBC viewers the chance to check the latest news headlines, sports scores, weather forecast or TV listings – in a pre-internet era where the only alternative was to wait for the next TV or radio bulletin to be aired.
Its premise was to give viewers free access to the same information that was coming into the BBC newsroom, as soon as the BBC’s journalists had received it.
Ceefax had initially been developed when BBC engineers, exploring ways to provide subtitles to enable viewers with hearing problems to enjoy BBC TV programmes, found it was possible to transmit full pages of text information in the “spare lines” transmitted on the analogue TV signal.
I was looking around for a comparison of what feels like the hundreds of capacitive touch sensors out there to find the best one for Adafruit (it’s more time consuming than you’d think!), and I came across an interesting page from Lion Precision detailing some of the many ways capacitive sensors are used for precision measurements in industrial settings (this stuff doesn’t just make its way into smart phones!). One of the more interesting was measuring glue thickness on paper with capacitive sensors. There’s even a short video that does a good job of illustrating the measurement process. Curious about some other potential uses of capacitive sensors or probes? Check out the application section here.
I’m always really interested in the way sensors get used in commercial and industrial settings, and it’s a great way to get the wheels turning in your own head. Have any interesting app notes or presentations on neat ways to measure things? … post them up in the comments below!
Hack Manhattan is teaching a KiCad class on Saturday, November 3. KiCad is an open source alternative to expensive commercial circuit board design packages, and supports 16 copper layers and unlimited board size. This workshop will assume working knowledge of circuit boards and what’s on them, but not any prior board design experience.
1962: Nick Holonyak, Jr. demonstrates the world’s first visible light-emitting diode (LED) to General Electric suits, changing the world of lighting forever. Holonyak later said that the LED would replace incandescent lights. It’s just taking a little bit longer than expected.
Scientists at the GE Advanced Semiconductor Laboratory were researching a way to create energy-efficient visible light from LEDs. The incandescent lights that we still use today rely on igniting a filament housed in a vacuum to create light. The process is inefficient and only uses 10 percent of available energy to produce light. The rest is lost as heat.
In the early 1960s, the only light emitted from LEDs was infrared. The race to produce a visible LED had GE researchers scrambling to be first.
In honor of this achievement, go out there and blink some LEDs!
We have decided to release the new Parts Editor in two phases. The first phase, included in the latest release (0.7.9), is already easier to use and more powerful than the old Parts Editor, but you still have to do a lot of preliminary work using an SVG editor like Inkscape, Illustrator, or CorelDRAW. In the next phase we hope to eliminate much of the need to use these programs.
A deal has been reached which will allow the Tesla Science Center to purchase Nikola Tesla’s Wardenclyffe property in Shoreham, Long Island. The property, previously owned by Agfa (a chemical and formerly photographic film company), was up for sale for $1.6 million USD. Matthew Inman, under the aegis of his online comic The Oatmeal, launched an indiegogo campaign to raise money for the Science Center organization which resulted in over $1.4 million in donations. More from the New York Times:
A dream of 16 years came true for science enthusiasts on Friday when they struck a deal to buy a dilapidated estate on Long Island and transform it into a museum and educational memorial to Nikola Tesla, an eccentric genius who lit the world with alternating current but died penniless.
The overgrown 16-acre site, in Shoreham, features his only surviving workshop. The crumbling brick laboratory was designed by Tesla’s friend Stanford White, a celebrated architect who drew up plans in Manhattan for the Washington Arch as well as neoclassical gems like the Century Club.
The Agfa Corporation, which owns the heavily wooded site and once operated a factory there, agreed to sell the estate to the Tesla enthusiasts for an undisclosed sum after they succeeded in raising $1.4 million through a Web campaign. The property had been listed at $1.6 million.
“All the terms and conditions have been accepted,” said John P. O’Hara, a real estate agent on Long Island who represents the property. “It’s all good. The stars have finally aligned.”
Agfa’s attorney, Christopher M. Santomassimo, confirmed the deal, saying, “We have reached an agreement.”
I’m keeping my fingers crossed that the new museum will include some sort of makerspace.