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December 2, 2016, Episode #44
- Popping in last weeks audio was probably due to a cheap USB cable. Stephen and Parker recorded last week on a laptop with a USB powered mic preamp that has less then stellar power filtering and performance.
- Stephen is continuing work on his automatic brewing rig. Has a motorized ball valve to control the flow rate for proper mashing and cooling rates.
- Parker found the correct IC that is inside the Jeep radio. Part number TDA7340S. It is a 100% direct match to the pinout of the IC inside the radio. He found it by looking at ST’s catalog of Audio and Radio ICs from that time period.
- To switch Audio sources to an external source, Parker is going to hack into the TDA7340’s external effects loop. See Figure 1. The signal will probably have a DC offset since the IC is on a single power rail of ~9.4V. DC offset should be around 4.5V. The Bluetooth adapter will need to have a DC offset to match. ICs to switch the audio signals will either be a NJM2520D or a MAX4544CPA+.
- Shout out to Pat Hensley from Tektronix. Came by the shop earlier this week to get a tour of the fab and show off some Tektronix goodies. Got to play with a Tektronix RSA306B USB Spectrum Analyzer. Which was really awesome. Real time over USB. Interface is scriptable with Python. Will be looking at getting one for pre-compliance testing.
- Attacking air gapped computers using the cooling fans. Basically a piece of malware tweaks the PWM on the fans inside the computer to transmit data audibly.
- Make your own nuclear battery. Using Tritium keychains and some solar cells to produce power. The battery produces 1.6 volts at 800 nano amps or 1.23 microwatts.
About the Hosts

Parker Dillmann
Parker is an Electrical Engineer with backgrounds in Embedded System Design and Digital Signal Processing. He got his start in 2005 by hacking Nintendo consoles into portable gaming units. The following year he designed and produced an Atari 2600 video mod to allow the Atari to display a crisp, RF fuzz free picture on newer TVs. Over a thousand Atari video mods where produced by Parker from 2006 to 2011 and the mod is still made by other enthusiasts in the Atari community.
In 2006, Parker enrolled at The University of Texas at Austin as a Petroleum Engineer. After realizing electronics was his passion he switched majors in 2007 to Electrical and Computer Engineering. Following his previous background in making the Atari 2600 video mod, Parker decided to take more board layout classes and circuit design classes. Other areas of study include robotics, microcontroller theory and design, FPGA development with VHDL and Verilog, and image and signal processing with DSPs. In 2010, Parker won a Ti sponsored Launchpad programming and design contest that was held by the IEEE CS chapter at the University. Parker graduated with a BS in Electrical and Computer Engineering in the Spring of 2012.
In the Summer of 2012, Parker was hired on as an Electrical Engineer at Dynamic Perception to design and prototype new electronic products. Here, Parker learned about full product development cycles and honed his board layout skills. Seeing the difficulties in managing operations and FCC/CE compliance testing, Parker thought there had to be a better way for small electronic companies to get their product out in customer's hands.
Parker also runs the blog, longhornengineer.com, where he posts his personal projects, technical guides, and appnotes about board layout design and components.

Stephen Kraig
Stephen Kraig began his electronics career by building musical oriented circuits in 2003. Stephen is an avid guitar player and, in his down time, manufactures audio electronics including guitar amplifiers, pedals, and pro audio gear. Stephen graduated with a BS in Electrical Engineering from Texas A&M University.
Special thanks to whixr over at Tymkrs for the intro and outro!
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