Want a radio project for beginners?

Not long ago I went out to the shed and found some old transmitter tubes, microphones, and other miscellaneous stuff in boxes from my days in radio. Going through the boxes, I noticed an old diode tube from back in the 30’s. It was HUGE and it got me to thinking about these old transmitters, tubes, and other electronics from bygone days… I knew a radio project was in order.There is something relaxing about watching old tubes warm up, softly glow orange-red, while perhaps flickering a little with the audio signal. Perhaps it was the extra thousand or so BTU’s of heat they pumped into a room to make it all warm and cozy that helped to make it so relaxing.

There is something relaxing about watching old tubes warm up, softly glow orange-red, while perhaps flickering a little with the audio signal. Perhaps it was the extra thousand or so BTU’s of heat they pumped into a room to make it all warm and cozy that helped to make it so relaxing.

For the project I decided to take this tube (it’s more than 13 inches tall) and mount it together with a microphone to arrange sort of an homage to old radio. Thinking about the glow, I decided that driving the heaters with the required voltage and pumping all that heat into the room wasn’t…. shall we say.. optimal, and decided to try to emulate the glowing/flickering effect with LED’s. Red LED’s wouldn’t do.. they were wrong color. Orange ones didn’t work either, so I decided to try Red-Blue-Green and mix my own color to get it right. Then, perhaps over-drive the LED’s to make them very bright (to light up the HUGE Tube), and finally, some automatic dimming and brightening to emulate that gentle flicker.  Sounds like a perfect job for an Arduino!

Project Problems

Any project – beginners or not – is going to have its issues.  Thinking about the glow, I decided that driving the heaters with the required voltage and pumping all that heat into the room wasn’t…. shall we say.. optimal, and decided to try to emulate the glowing/flickering effect with LED’s. Red LED’s wouldn’t do.. they were wrong color. Orange ones didn’t work either, so I decided to try Red-Blue-Green and mix my own color to get it right. Then, perhaps over-drive the LED’s to make them very bright (to light up the HUGE Tube), and finally, some automatic dimming and brightening to emulate that gentle flicker.  Sounds like a perfect job for an Arduino!

Project Result!

A collection of 3 Hi-intensity tri-color LED’s, a little bit of code, a wood plaque, drill, router and stain, and I wound up with this:

Total cost was under fifty bucks, and the time spent was about two hours. Not a bad result, I think.

In part 2 I’ll discuss the schematic, the code, and the parts, so that you can make your own version of this neat display item.

‘Till next time.