I found this helpful diagram on how much current an Arduino can handle on its pins.
Sometimes you need to be able to turn devices on and off from your Arduino. If the current being drawn is low enough (under 40 Ma MAX, 20Ma recommended) then you can just use the IO pins of the controller to turn the device on and off. The Blink example program does exactly this with […]
In the early days of radio, hams used Morse code to communicate over radio. The speed of sending Morse code, like the speed of a typist, depends on the skill of the operator. Typical Morse speeds might be around 13-20 words a minute. Having to send a commonly used phrase like “Can you change frequency […]
WSPR How low can you go? (And still be heard) As part of my Flying Squirrel project, I wanted to know, “Would my little Si3551A based telemetry transmitter,sending WSPR, ever be heard by anyone?” So I conducted the following test. I configured the Radio gear to send the absolute minimum signal possible, on the 20m […]