At one of a our nerdy amateur radio rallies a couple of months back, a mate of mine bought a box of old crystals.

Of course, I am not talking about a bowl of crystals used for aligning your chakra, or shit like that, but quartz crystals that have been cut and shaped, such that they will resonate at a particular frequency when a voltage is applied to them, making them useful for making accurate oscillators for clocks and watches… and radio transmitters, of course.

My mate was bemused when he found a crystal in the box that was stamped with his date of birth… or near enough, anyway.

He also found one that had my birthday (month and year) stamped into it and he sent it to me.

And so, I made a simple oscillator with it. That’s it in the above picture.  The yellow LED is set to flash at 1.2Hz. That’s equal to 72 times a minute – the average human heart rate at rest.

It’s battery powered and I’ve added a trickle charger to it,  using two small solar panels (the black rectangles behind the battery), so, in theory, it should be able to just sit on my windowsill, flashing away almost indefinitely (well, within reason).

The idea is to see which gives up first… the crystal or my heart… bearing in mind they are the same age.

Rather like Liz Truss and the lettuce, it’s just a bit of fun.