Solid State Speech Synthesizer

PHP1500a PHP1500b
In 1978, Texas Instruments introduced the first single-chip linear predictive coding speech synthesizer, the TMS5100 (also known as the TMC0280). The Solid State Speech Synthesizer for the TI-99/4A used the TMS5200 (TMC0285).
Continue reading “Solid State Speech Synthesizer”

Buy 2, Get 1 Free

charger When I found the ’67 Camaro I mentioned in a previous post, the store had a promotion where if you buy two Hot Wheels cars you get a third one for free. But I was not interested in any of the remaining cars on display. So I asked a saleslady to get a few more Hot Wheels from storage. She came back with an armful of cars and I nonchalantly got the first one I saw. I now had two cars (the ’67 Camaro and this second one) and for the third car I had two candidates: a chrome The Gov’ner and some muscle car with a nice tinted chrome base. My wife and daughter didn’t like the chrome car, so I got the muscle car. I had unwittingly chosen a Fast & Furious ’69 Dodge Charger Daytona.

batman13 The second car was a 2013 Batmobile (the “1989” version). (I explained how hard it is to get a main line Batmobile in an earlier blog post.)

’67 Camaro

camaro67 My wife and I do not collect scale models of muscle cars, but earlier today I saw a 2013 Hot Wheels ’67 Camaro that was so beautiful that I just had to buy it. I thought it was very unusual for a main line Hot Wheels because it had a metal base, a metal body, and an opening hood.

After searching the internet, I discovered that there is a Super Secret Treasure Hunt version of this car. There are also many variations of it. Some have a Hot Wheels logo on the base, while others don’t. Some have a raised dashboard, while others don’t. I’ve heard that some have the motor painted black, while others have the motor unpainted. There are also variants with no door handles or door lines, with door handles only, with door lines only, and with door handles and door lines.

Mine is a main line version with a logo on the base, a raised dashboard, and no door handles or door lines. (I’m not opening the blister pack, so I’ll never know if the engine is painted or not.) Its base code is F16, so it was made around the third week of April 2013.

Shirriff’s Sinclair Scientific simulator

Ken Shirriff has reverse engineered the Sinclair Scientific, an incredible 12-function scientific calculator made by Sinclair Radionics in 1974. (I got the picture on the left from here.) He reports the details here. According to his August 30, 2013 blog post:

I’ve reverse-engineered the Sinclair Scientific calculator. The remarkable thing about this calculator is they took a simple 4-function calculator chip and reprogrammed its 320-instruction ROM to be a full scientific calculator. By looking at the chip, I’ve extracted the original code, reverse-engineered how it works, and written a JavaScript simulator that runs the original code and shows what the calculator is doing internally.

2014 Bicol Mathematics Conference: Call for Papers

The 2014 Bicol Mathematics Conference will be held on February 7–8, 2014 at the Ateneo de Naga University. We are inviting mathematicians and mathematics educators especially those in the Bicol region to present a 30-minute talk. More details can be found in the call for papers.

First-order LSEs with constant coefficients: Repeated roots

I’m currently teaching an undergraduate course on ordinary differential equations using the 8th edition of Elementary Differential Equations by Rainville, Bedient, and Bedient (published in 1996 by Prentice Hall). I’ve always wanted to have a blog post containing some LaTeX (using the plug-in WP LaTeX), so in this blog post I’ll be showing my solution to one of the exercises in the book.

I will derive the solution to a first-order linear system of two (ordinary) differential equations with constant coefficients for the case where the characteristic equation of the (constant coefficient) square matrix has repeated roots.
Continue reading “First-order LSEs with constant coefficients: Repeated roots”

Casio A159WGEA-4AEF and A159WGEA-9AEF

These two beauties deserve a blog post of their own. (Click on the pictures to see where I got them from.) The one on the left is what I want; it stands out quietly, saying “yes, I’m beautiful, but I’m humble about it.” (I just showed the one on the right for context.) The Casio employees who designed these should get promoted.

Casio Classic Digital Watches

f91w-1_xlarge w59-1v_xlarge
When I was in high school, I wore a simple Casio digital watch with a black resin band (most likely an F91W-1 like the one above left, but possibly a W59-1V like the one above right). It seems that Casio has created newer versions of these classics, the A158WA-1 and the A159WGEA-1EF, and this time they have stainless steel bands. (Click on the pictures to see where I got them from.)
a158w-1_xlarge 1328737470906