hardware – matei repair blog

SimpleFOC BLDC Motor Drivers

Several months, ago, I stumbled across the “Smartknob” project by ScottBez1. The idea is really interesting and quite captivating for people who love interfaces. In essence, a magnetic encoder is used to sense the rotary position of a knob. However, the knob is actually a small motor- a special type called a brushless DC motor “BLDC”. Because it’s a motor, we can drive it towards or away from points – both continuously and discretely – to provide ‘haptic textures’ and user feedback. So, this opens up many doors to different user experiences- springing knobs, clicky, knobs that keeps spinning after you let go- very cool things.

HP 1670D notes

I have finally gotten around to setting up the logic analyzer I picked up locally to replace the HP 1652B. It’s a really nice instrument- 136 digital channels, LAN connectivity, keyboard and mouse support, internal mass storage, and some other nice features. Here are some notes on how I set up and used some of the features- they are generally not well documented and there are some modern upgrades we can do to make working with it easier.

SNES repro boards 2

Alright, so we’ve got the main parts for our board picked out based on the specs we want to meet. How do we hook it all up? Let’s start with the ROM.

SNES repro boards

A while ago, I got interested in making SNES repro boards. This was part due to the cost of genuine copies of some titles, and half in the interest of playing some of the the SMW hacks that have been released online (or maybe making my own!) I have never really built any hardware that interfaces with a CPU before, so there was a lot of learning to be done. This will be a multi-part post since there is so much material to cover.

Pioneer SA-9100 noisy channel

A few weeks ago, I fixed the issue with the protection circuit. I forgot to document the repair, so I’m going to go back later and write up what the issues were if anyone else needs to read that. Since then, it’s sounded pretty good, but recently after a while of listening (about 1-2 hours) the left channel will drop out due to some noise. It makes it unbearable to listen to, and the volume knob doesn’t do anything to lower the static, just the right channel.

hp 1652b rs232 USB adapter

A while ago, I bought an HP 1652b logic analyzer. It’s a great machine, and works very well for my purposes (monitoring address and data bus for SNES memory usage) and I’m sure it will be invaluable in future projects, especially anything including parallel or serial data transfer. However, the only way to get data off of the analyzer is printing to a dot matrix printer/plotter through an antiquated RS232 or GPIB port. Those aren’t really common or useful anymore, but hopefully that does mean we can capture the data as a digital image for keeping around on our PC. This is a short documentation of my research and application process on creating an adpater to capture the signal on my PC.