I have just one thing to say (it’s at the bottom of this post).
Since I was a teenager fooling around with electronics, I’ve had trouble understanding transistors. Not the big things: they can amplify; they can act like a switch. But the little things: forward-this; leakage-that.
Lately, I’ve been performing a “run dead” test. I have an ATtiny processor running from two AA batteries. It sends status information to an Arduino running from USB power. The goal is to run the test until the batteries are dead. As expected, when the batteries reached about 2.3 volts, the ATtiny was no longer able to communicate reliably. The ATtiny Sketch was running fine. The output voltage just wasn’t enough to reliably trip the Arduino’s inputs.
Time for a level shifter. Only, I don’t have one. Time to make a level shifter. Only, I don’t have a clue how to build one. And then I remembered this…
I reread that thread and everything clicked! I now have a pair of low-voltage to 5V transistor-switches. I was even able to tweak the resistors without blowing up anything. A few more transistor-switches under my belt and I may be able to fly solo (not have to use reference material)!
So, I have just one thing to say … THANK YOU! To retrolefty, Grumpy_Mike, EmilyJane, and pwillard … THANK YOU!