Archive for May, 2007

Programming (MCU)

Tuesday, May 22nd, 2007

I finally sat down the other day and programmed my first microcontroller (MCU) since my college days back in the ’90s. I had purchased the Olimex PIC-PG1 ICSP Microchip PIC programmer and the Olimex PG1B Atmel AVR ICSP programmer a little over two years ago but had never gotten either to work successfully so both of them have sat on the shelf collecting dust.

Enter Sparkfun’s nifty PIC programming tutorial and a lazy Saturday afternoon and I finally had success programming the PIC16F628. Next up, I’ll be attempting the same process with an Atmel AVR MCU. Watch here for future MCU projects!

Loose Hardware

Sunday, May 13th, 2007

A short bit of history is in order before getting into the meat of this story. I purchased a 1987 Toyota Supra in February, 2006. While sorting it out I found numerous items on the engine that were loose including, but not limited to, both valve covers; the turbo to exhaust manifold connection; the exhaust manifold to head connection; and some of the intercooling piping. It seemed like every time I worked on the car, I was finding something loose and became the big joke during days I put in wrenching on it.

This leads my readers into the current story. I had finally gotten time to adjust the emergency brakes. They had never worked since owning the car, and following the Toyota factory manual procedure, I remove the rear wheels and began adjusting the “star” adjuster inside the rear disc hats. Come to find out they were not seized, but in fact extremely loose and could be rotated with ease. I was able to adjust them to the proper tension and the emergency brakes were working as if new.

Next, while I still had some time, I started jacking up the front of the car to change the oil filter. While jacking up the car I noticed the passenger side front wheel moved a significant amount inward as soon as it left the ground. Now, the previous owner told me the bottom ball joint had been replaced on this particular side so it was immediately suspect. Upon inspection of the wheel bearing play and upper and lower ball joints, I found that the nut had not been tightened to the proper torque on the bottom ball joint. In fact the nut was nearly flush with the top of the ball joint stud and the wheel assembly could be moved what seemed like nearly 12.7mm to 25.4mm! Once the ball joint hardware was tightened to the proper torque, all tolerances checked out. Luckily there had been no accidents or damage caused by this loose hardware.