Sine – Cosine Approximations

OK, this is supposed to be a technical web site. It’s about time I posted something technical! Actually, this is just a link to a white paper I posted in the Digital Designs section.

A microprocessor-based design needed to create a circular motion by using the cosine and sine functions to drive X and Y positioners. The exact equations for these functions are infinitely long polynomials, so approximations are needed. We studied three possibilities, each with different tradeoffs between accuracy and speed.

If you ever need to compute sine and cosine, here’s the link: White Paper: Simple Sine Approximations.

Why SRQ?

Aerial view of Siesta Key beach in Sarasota, FL

SRQ Technology? What a unique name! What does SRQ stand for?

Good question. It’s not anyone’s initials. I’ve racked my brain trying to think up something catchy. Maybe Superior Reliable Quality? Supplying Results Quickly? Solving Rough Questions?

Don’t like those? Well – let’s try Stinking Rotten Quagmire, Stop Ridiculous Quibbling or Seems Really Quirky. Ugh! Enough!

OK – SRQ is the official designation for our Sarasota-Bradenton (Florida) International airport. I read that around 1956, when the three-letter designations were created, SR was felt to be recognizable as Sarasota. Q was added to make it unique. Since then, it’s become the local shorthand for Sarasota. We even have an SRQ Magazine. (Also, Sarasota Magazine.) I did a bit of searching and found:

  • SRQ Custom (auto customization)
  • SRQ Fabrications (also auto related)
  • SRQ Media Group
  • SRQ Vets
  • SRQ360 Photography
  • SRQ Blinds and Drapes
  • SRQ Woodwork
  • Gym SRQ
  • Lab SRQ

And a few others. So, SRQ Technology isn’t so unique after all.

Now, the commercial. Please keep us in mind if you need circuit design or technical writing services.

My Electronics Workbench!

Warning – commercial coming!

Here’s where I breadboard & test my fantastic electronic creations. Look – you can see an oscilloscope, a small meter and part of a lab power supply! The soldering iron is almost hidden behind the saw.

But now, honey-do time. My wife, Jacquie, makes and sells fashion doll (Barbie) accessories. Much of what she does involves clay and resin casting but when she needs wood pieces for furniture and lamps, that’s where I come in.

I enjoy it. I’ve always liked working with wood. Not a master craftsman, but I’ve built a few cabinets, shelves and display tables. Just stained plywood, nothing fancier.

Now, the commercial. She has a business – sells her Barbie/fashion doll crafts on Etsy.com. The direct link to her store is OneSixthRestaurant.com. Why the name? She started with Barbie-size food, dishes, dinners etc. and Barbie is 1:6 scale. Here’s an example of her furniture.

Free Photo Source

Here’s a source I found for free photos – Unsplash.com. You also can join and contribute (upload) your own photos for (free) use by others.

I’ll repeat a few key sentences from their web site. Visit the site for full terms and license.

  • All photos can be downloaded and used for free.
  • Commercial and non-commercial purposes.
  • No permission is needed (although attribution is appreciated).
  • Photos cannot be sold without significant modification.

The license does not include the right to use:

  • Trademarks, logos or brands,
  • People’s images if they are recognizable,
  • Works of art or authorship

that appear in photos. If you download photos with any of these depicted in them, you may need the permission of the brand owner of the brand or work of authorship or individual depending on how you use the Photo.

This is not an endorsement. They have not paid anything for this blog post. I’m just sharing it because I found useful. Hope you do, too.

(Photo by Benjamin Combs on Unsplash)

The Housewife-Engineer

Here’s some “engineering” information I found while doing random reading on Wikipedia.

Mary Wright was a designer/author/business woman. In 1950 she and her husband, Russel, wrote a best-selling book, Guide to Easier Living. Its goal, per Wikipedia, was to “increase leisure time and reduce housework through efficient design and time management”. You can still find it on Amazon.

One chapter is titled, The Housewife-Engineer. It encourages readers to (quoting the Wikipedia article again), “analyze and perform time-motion studies in ordinary household tasks”. The home is “a small industry and every housewife is its production engineer”. Lifestyle choices are like “engineering problems with scientific solutions”. It even includes an illustrated 32 step chart for “scientific bedmaking”.

Housewife-engineers? Let me ramble a bit. In the 1960s, when I started working, female engineers were very rare, more so than today. A person who did technical drawing was a draftsman, not a drafter. If I called a technical company or distributor and a woman answered I could safely assume she was not a technical person. The help wanted ads in newspaper were still divided between “Help Wanted – Male” and “Help Wanted – Female”. Now we have a daughter who is an electrical engineer – a PhD! The other is a PhD equivalent, a nurse practitioner. How the world has changed – much for the better!

Florida State Bird

There’s a move afoot to replace the Florida State Bird. A state senator plans to introduce a bill in the 2022 legislative session. Currently it’s the Northern Mockingbird, which also is the state bird of Arkansas, Mississippi, Tennessee and Texas. Some would prefer a bird that’s more uniquely identifiable as Florida. Besides, how can the southernmost state (except Hawaii) have a “northern” state bird?

Suggestions include the osprey, the flamingo (although it’s not clear whether it is native to Florida) and others. Some people think Florida’s state bird should be the construction crane!

Photo credit: Wikipedia

Me – Under 30?

Memories! That’s me, together with several cohorts, somewhere around 1970. An engineering recruitment ad for Taylor Instruments, where I first worked as an engineer.

If you’re as old as me you’ll remember, “Don’t trust anyone over thirty.” Attributed to political activist Jack Weinberg in 1964, it became a slogan in the integration/free speech/antiwar movements in the ‘60s and ’70s.

Here’s an earlier version. “Every man over 40 is a scoundrel.” (George Bernard Shaw in an appendix of his play, Man and Superman,1903).

The Huffy RadioBike

When I was a kid I saw an ad for a new bicycle with a built-in radio. What a dream! Like any other kid I dreamed of one, but it never happened. But – read on!

The Huffy RadioBike, made by Huffy Bicycle (Huffman Corporation) of Dayton, Ohio, came out in 1955. The radio was in the “gas tank” between the handlebars and the seat. It ran on three vacuum tubes and  turned on and off with a key – just like Dad’s car. AM only in those days.

Vacuum tubes needed high voltage & large batteries: you can see the power pack mounted above the rear wheel. Poor battery life –  and expensive. Transistor radios were brand new. An article I read said they came out about the same time but cost about $40, almost as much as the RadioBike. Remember, this was 1955, the same year the US minimum wage was increased to $1.00 per hour. Only about 8,500 were ever built. It was available for 2-3 years. I didn’t get either a RadioBike or a transistor radio!

Fast forward to 1978. I took an engineering job with Yellow Springs Instruments (now YSI). Yellow Springs, Ohio is a small village/college town about 20 miles (32 km) east of Dayton.

Imagine my surprise when I found a RadioBike tank on the marketing Vice President’s bookshelf, complete with a radio. YSI had made them for Huffy!

Here’s the circuit schematic drawn by Hardy Trolander, engineer, one of the founders and the first President of YSI. One of my favorite people.

PS: 50-plus years earlier Dayton was home to the Wright Brothers’ bicycle shop. Huffman began in the late 1800s, so I’ll bet they knew each other.

References: Huffy Radiobike – American Vintage Bicycles (american-vintage-bicycles.com).

1955 Huffy Radiobike – The Online Bicycle Museum.

1955 Huffy Radiobike | www.Oldbike.eu (wordpress.com).

Chip Shortages

You’ve surely heard about the electronic chip shortage even if you’re not in the electronics industry. TV news tells us how auto production is being slowed because of delayed microcomputer chip deliveries.

I just read an article that says Apple is facing shortages and delays of radio frequency (RF) ICs (integrated circuits), and chips for brightness and color control and power management. Production of Macs and iPads is already being impacted, and they expect it to start slowing production of iPhones in the 4th quarter of 2021.

Well, it’s hit SRQ Technology, too. Not as directly – we don’t manufacture anything other than occasional prototypes, but we’re sometimes asked to help find alternative parts. Elsewhere on this site you’ll see examples of things we’ve designed for other companies. Sometimes these companies use Harry’s former company, JH Technology, for production. JH turns to us for help when they run into parts problems.

The latest – a simple, low-cost 8-bit Microchip PIC microcontroller. They needed only a handful for a short run but the chip was unavailable from several distributors. Deliveries were projected anywhere from October 2021 (I’m writing this in August) out to next year. The design uses an 8-pin surface mount (SOIC) industrial grade version; however, it was unavailable in other versions, too.

We searched for other 8-bit, 8-pin PIC microcontrollers. We found one, similar but not identical, with enough in stock at one distributor to meet the need. Unfortunately, the differences will require some reprogramming. JH bought some. Problem solved – maybe. We’re waiting to hear if their customer (our former client) wants to pay for reprogramming or will just wait until the part they need is available. A second IC also was short, but we found a substitute.

By the way, it’s not just ICs or chips. We in the industry have known for some time about capacitor shortages; especially ceramic multilayer chip capacitors (MLCCs). Simple, basic parts but one cell phone or one car can use hundreds. Resistors and other parts, too. The Covid-19 impact on shipping is part of the problem – they’re mostly produced in China and elsewhere overseas. This all is projected to continue well into 2022.

(Photo by Chris Ried on Unsplash.com)