At first, I was exciting agile software development weaves. I made XFD device in 2006.
It was very standard formal style, using the signal light.
I did have no idea how to communicate easy way between PC/Server and devices. So I made with PC’s printer parallel port.
Today, we can communicate easier using a lot of procedures, USB/LAN/Wifi/Bluetooth and more. The parallel port obsoleted.
I’m beginning to redesign for modern-style device communication. The ESP8266 totally better balanced module for IoT platform. I use ESP8266 and redesign XFD for basic boilerplate :)
History
first_pcb: Designed output signal with darlington transistor array. It’s very simple board, contains only ESP-WROOM-02 and TrA.