Favorite Embedded Projects 2015 - 2019

Here are a few of my favorite embedded projects from work and personal projects over the years 2015 - 2019.

The ControlWidget was one of my first widely used generic microcontroller platforms. Based on a dsPIC, the platform was used to control various RF devices, front panel connections (buttons and status LED's), high voltage power switching, and temperature monitoring. It supported the following features:

• Serial command interface to access GPIO and basic signal processing algorithms
• USB serial for connection to laptops or SBC's (single board computers)
• Lantronix Ethernet to Serial module for remote network connections (using the same serial command interface)
• USB or external 5V power
• Optional high voltage (9 - 24V) power connection for high voltage signal monitoring (input) and power switching (output)
• Jumpers to select 3.3V or 5V for each 8-bit GPIO bank
• Temperature and humidity sensor

The PicLeaf system was an evolution in how I architected digital control systems. Instead of using a fixed controller board, I created a multiple devices that all communicated over an RS-485 network. The PicLeaf Hub (pictured below) had an Ethernet port and two isolated RS-485 networks. Other PicLeaf devices could be connected to each network, and device addresses and type are configured by DIP switches. Software would run on a tablet computer, and a configuration file would inform the system which devices should be connected on the network. The software would then dynamically generate a GUI to control each device.

The PicLeaf Hub features the following:

• PIC32 Core on detachable module with integrated LAN8720 Ethernet PHY
• Fully controllable over USB serial, custom TCP and UDP protocol implementations
• 7 - 36 VDC input with SMPS down to 5V
• Two GPIO banks, configurable as input or output and at 5V or 3.3V
• Two RS-485 network connections over DB-9 with replaceable driver IC's (they blew up sometimes)
• One RS-232 port for external device control
• USB Serial for debug connection (debug serial also available on UDP port)
• Temperature and humidity sensor

Sometimes you need the processing power and network connectivity of a Pi but also an embedded device to take care of some faster tasks. This was the basis for my ESP32 gateway, which helped managed a variety of inputs into a data collection service running on the Raspberry Pi. My ESP32 Pi Gateway featured the following:

• ESP32 microcontroller configurable for either WiFi SSID, Bluetooth Classic, or Bluetooth Low Energy device scanning. The ESP's radio was much easier to manipulate and significantly faster scanning was achievable on the ESP than what the Pi was capable of doing.
• uBlox GPS receiver with external antenna
• LoRa transceiver
• 3x SMA connections for each radio (ESP32, GPS, LoRa)
• Real Time Clock (RTC) module with backup battery
• microSD card for backup logging

The Tea Earl Gray Hot Bot was my entry to the 2019 Alternative History Teacup Robot Race at DragonCon. This informal competition required a remote controlled robot with a tea theme to traverse an obstacle course. The robot features the following:

• Raspberry Pi core with Python script controlling the robot
• Adafruit motor controller on tracked robot base
• HDMI screen to display picture or video (why not??)
• Steam Controller for remote control
• 10W Audio amplifier with audio isolator to prevent noise
• Fancy DAX Lights on the bottom for a cool effect
• 6 quotes of Jean Luc Picard saying “Tea, Earl Gray, Hot” from Star Trek: The Next Generation.

The Tea Earl Gray Hot Bot won first prize that year!