Building the $3 DIGI MODE Interface

Описание: GitHub repository with documents and pictures referenced in the video:
https://github.com/radiohyperactivity...

Table of Contents:
00:00 Introduction
00:50 Bill of Materials
02:30 The Enclosure
03:10 Assembling the PTT Buffer Circuit
08:30 Removing the TRS Connectors from the Sound Card
11:30 Installing the Sound Card in the Enclosure
13:00 Connection the Capacitors and Potentiometers
17:40 Connecting the GOIP3 Pin for PTT Control
18:55 Soldering the USB-C Connector
20:00 Soldering the "Kantronics" Connector
21:20 Soldering The Ground Wires
21:45 Microphone and headphones circuit
22:50 Re-doing the "Kantronics" Ground Pin
23:20 Connecting the Radio AF-OUT Pin
23:40 Connecting the Radio AF-IN Pin
24:00 Installing the PTT Buffer Circuit
26:20 Finishing up

After one of my previous videos it was pointed out to me on more the one occasion the irony of showing of a $10 radio while pairing it with a $150 Mobilinkd and a $900 iPhone. And I tend to agree that this defeats the purpose of an inexpensive radio. So; this week I'm building a $3 digi-mode interface.

My first DIY digi-mode interface to do APRS was built on Stripboard and connected the radio via a generic USB sound dongle. PTT was handled with GPIO from the controlling Raspberry Pi. With two trimmer pots to set the in and out audio level it worked well enough. But I wouldn't want to bring that thing through airport security. Join me as I build version 2, based around the CM108 - a USB sound card that also has PGIO to handle PTT. Building it all into a nice enclosure, with proper potentiometers, a Kantronics compatible DE9 connector in one end and USB-C in the other. Looking at it, I have to say the soldering is not something I'm particularly proud of. Other then that the result turned out quite nice - both visually and functionally!