Posts in Year 2020

MICROSCOPE FOR ELECTRONICS REVERSE ENGINEERING

Electronics is getting tinier and my eyes are getting older. To be able to re-use old hardware, sometimes it is necessary to:

• discover the JTAG, SPI, I²C or UART pins on the circuit board, or
• extract and/or reload firmware correctly without damaging the board, or
• check the quality of the connnections of the main processor chips, or
• map the pins of the main processor back to a datasheet, especially with custom ASICs and System-on-Chips (SoCs) being made based on standard designs but by arbitrary vendors.

I saw this post on Twitter, got excited and ordered a full microscope which could do 300X zoom from AliExpress. This took a month to arrive, but was an exciting wait.

The microscope and the stand arrived last Friday, and I assembled it myself. However, it does not have an assembly manual so this post will act as one.

RE-PURPOSE SATELLITE DISH TO CUSTOM DIRECTIONAL ANTENNA

Keeping the theme of re-using old hardware, I have always wanted to build a directional antenna from an old satellite dish and this is what I demonstrate in this post. I wanted it to look professional so no zip-ties were used. I also wanted the directional antenna to be generic and not limited to just a WiFi dongle. Using a 10’ SMA-connector extension wire from Amazon, I was able to pass this through the LNBF assembly that comes with the satellite dish, and convert it to a professional looking re-usable directional parabolic antenna. This is more generic than strapping a USB WiFi dongle using zip-ties, and can be used for any other radio that accepts an antenna with an SMA connector. Here is how I did it.

PLAYING PLAYSTATION 2 GAMES USING NETWORK SHARE

Keeping the theme of re-using old hardware, I decided to take the non-working PlayStation 2 (PS2) off my brother’s hands and try to get it to work. The CD/DVD reader had stopped working and after a few tries I gave up and decided to use the FreeMcBoot bootloader to modify the PS2 so that it could load games off an SMB share on the network. You have to use a wired ethernet connection for this. Here’s how to do this in the year 2020.

PLAYING WITH OLD CISCO® IP PHONES

Cisco® IP phones are generally found everywhere in offices for the last nearly 20 years. As of this writing, there are several models that have reached their end of life and official support from Cisco®. One such model is the CP-7961G-GE which I was able to get on eBay for $15.99 with free shipping, so I purchased two of them. I also ended up purchasing the CP-7975G for $18 with free shipping. When purchased new these phones cost more than $200 to buy one.

This is going to be a series of posts in my adventures with these phones, with this being the introductory one. Several people have setup these end-of-life phones with Asterisk or FreePBX and I will be doing the same. In addition to that, I will try to get to the internals of the phone and understand the chipset and write applications that run on the phone.

NEW LIFE WITH JEKYLL!

After more than 10 years of using a custom Perl script to generate this static website and not making any updates to it, I have finally gone the distance and converted the site to work with Jekyll which is written in Ruby, a language that I can read but cannot write. This brings my site into the modern world of using Markdown to write my pages and posts, and be able to add information much more quickly than I would do with my custom Perl script. The CSS theme is still the same ncurses-style old-school retro look of a DOS terminal from the 1990s, that I had developed around 2010 from scratch and continue to use. Although, I did switch to using Monospace font as a default for readability.