In this issue

6: The Amazing Electret: Near-Permanent Charge Without a Voltage Supply, By George R. Steber
14: Remote Updating of Microcontroller Firmware: Using an ESP32 MCU and Apache HTTP Server, By Pedro Bertoleti
22: Software-Defined Radios: Their Use in Testing & Measurement Applications, By Brendon McHugh and Kaue Morcelles
28: GUI-O: A “Virtual” Front Panel: For ESP32 Projects, By Brian Millier
39: Automated Test Suite: The Selection, By Michael Lynes
46: DATASHEET: Tiny Embedded Boards: A Range of Powerful, Ultra-Compact Options, By Sam Wallace
50: THE MAGIC SMOKE FACTORY: Smartphone App with ESP32, By Joseph Corleto
58: EMBEDDED IN THIN SLICES: Debugging Embedded Real-Time Systems: Tools Needed to Debug On the Go, By Bob Japenga
62: START TO FINISH: Introduction to Impedance: What is It, and How it Applies to Embedded Systems, By Stuart Ball
68: From the Bench: Just How Fast Was I Driving, Officer? Build a Solar-Powered Radar Detector, By Jeff Bachiochi
78: Test Your EQ
79: TECH THE FUTURE: The Future of Data Centers: It’s Time to Rethink Data Center Architecture, By Vito Savino

Circuit Cellar Magazine Description:

Circuit Cellar magazine features engineering tutorials, detailed microcontroller-based projects, and embedded systems industry news for professional electrical engineers, EE/ECE academics, and highly skilled electronics enthusiasts. Since 1988, Circuit Cellar has featured projects and tutorials from the world's top engineers on subjects such as embedded development (e.g., prototyping and programming), signal processing (e.g., DSP chips and signal conditioning), programmable logic (e.g., FPGA projects), sensor systems (e.g., smart sensors and MEMS), 'Net-connected devices (e.g., IoT projects and protocol stacks), robotics (e.g., robotic systems and proximity sensing), and much more. Circuit Cellar is the ultimate resource for all of your electrical engineering-related needs.