Posts with «perfboard» label

Homebrew Multimode Digital Voice Modem

There’s an old saying that the nice thing about standards is there are so many of them. For digital voice modes, hams have choices of D-Star, DMR, System Fusion, and others. An open source project, the Multimode Digital Voice Modem (MMDVM), allows you to use multiple modes with one set of hardware.

There are some kits available, but [flo_0_] couldn’t wait for his order to arrive. So he built his own version without using a PCB. Since it is a relatively complex circuit for perf board, [flo_0_] used Blackboard to plan the build before heating up a soldering iron. You can see the MMDVM in action below.

The build includes an Arduino, of course, and the neat perf board wiring makes for a good-looking project. We’ve covered digital voice that uses PCs before and even some digital ham modes that use an Arduino. Or check out the MMDVM project for more info.

Filed under: Arduino Hacks, radio hacks

Hack a Day 24 Mar 00:00

arduino arduino hacks blackboard d-star digital voice dmr ham radio mmdvm perfboard radio hacks

Tracking Solar Brightness with a Homemade Sun Logger

The Sun Logger, a data logging device, combines several components we’ve used in previous Weekend Projects. You may recognize the light-sensitive photoresistor (Optical Tremolo Box) and the Arduino Uno microcontroller (Touchless 3D Tracking Interface). These parts, when combined with a 74AHC125 Level Shifter and SD card socket mounted on a homemade “shield,” will record the levels of light shining down on your project box. That data, recorded every 15 seconds to the SD card, can be exported later to any popular spreadsheet software and graphed, giving you a visual representation of light changes over time.

This data could aid in knowing where best to plant a garden, or simply to understand changes of light intensity throughout the seasons in your micro-climate.

And while this project is readymade for recording levels of sunlight, the Arduino has a total of six analog inputs (labeled A0 – A5) and could easily record other variables. For example temperature, motion, or barometric pressure. Makers looking for a mid-level Arduino build, or knowledgeable coders looking to solder together their first homemade shield, the Sun Logger is a great project to build!