The Tiniest Of 555 Pianos

The 555 timer is one of that special club of integrated circuits that has achieved silicon immortality. Despite its advanced age and having had its functionality replicated and superceded in almost every way, it remains in production and is still extremely popular because it’s simply so useful. If you are of A Certain Age a 555 might well have been the first integrated circuit you touched, and in turn there is a very good chance that your project with it would have been a simple electric organ.

If you’d like to relive that project, perhaps [Alexander Ryzhkov] has the answer with his 555 piano. It’s an entry in our coin cell challenge, and thus uses a CMOS low voltage 555 rather than the power-hungry original, but it’s every bit the classic 555 oscillator with a switchable resistor ladder you know and love.

Physically the piano is a tiny PCB with surface-mount components and physical buttons rather than the stylus organs of yore, but as you can see in the video below the break it remains playable. We said it was tiny, but some might also use tinny.

We could take you to any of a huge number of 555 projects that have graced these pages over the years. But since this is a musical instrument, maybe it’s better to suggest you accompany it on a sawtooth synth, or perhaps a flute.

23 thoughts on “The Tiniest Of 555 Pianos

    1. I am so old that the first thing I made was a detector radio with a germanium diode (If I don’t include electromechanical stuff made by erector-compatible parts electric experiments kit).

    2. I’m so young the first thing I made was a seed planting robot using an arduino and a couple of motor controllers. Why would I want my first project to be an oscillator or a 555 timer? It sounds pretty boring…

    3. Yes, my second project was an electronic organ, complete with keys cut from tin cans. I think it used a pair f transistors, it never did work.

      Oddly, many of those simple electronic organ projects use unijunction transistors. Those have similarity to the 555 when generating a tone (a ramp across the timing capacitor, small pulses to the speaker, so it’s no wonder the 555 has taken over.

      I can’t remember my first IC. They were doing well already in 1971. Maybe a uA723 voltage regulator, I needed a power supply. Maybe it was an op-amp, but I can’t remember. I remember about 1974 ordering a Motorola MC1648 VCO and an MC4044P phase detector, but I don’t remember a sequence. Maybe it was some ICs I got from Poly-Paks. I remember reading about 3-terminal regulators when they hit hobby circles, and getting some soon after (actually surplus, they were TO-5 mounted on het sinks, very useful.

      I think someone gave me the first 555 I got. And sometime later, 1975 or 1976, someone gave me a whole tube of 555s. That tube still has some inside.


  1. Yes, the 555 was a clever part in it’s day, and I fired up a few of them when I was a young lad, but I haven’t used one in a design in maybe 15 years. It just never seems to be the solution anymore.

  2. Seemingly people above (barring jonsmg) are tone deaf… as I could definitely hear the tones. I’ll admit the frequency difference between the tones at each end of the “piano” isn’t quite as wide as one would expect for a piano… and the convention is backwards to most pianos, but still… it does make noises.

  3. “Still in production” might be a bit of a stretch.

    The 555 is something that you, as an owner of an old (and long paid-off) semiconductor fab run when you currently don’t have any demand for your higher margin products, or when you need to quickly clean your machine after it might have been contaminated and need something of which you can, without much pain, throw away half a wafer or two.

    So, TI certainly doesn’t produce 555s because it’s still a profitable mass product that they’d recommend for new design – it’s just that the masks are so ham-fisted that you probably can bake half a rat into a wafer and still use some of the dies.

  4. Could someone design a similar circuit on a cylinder, or in a glove?

    I ride a bicycle to go to and from work (40 min each way). I listen to my iPod and drum my fingers on my handlebars.

    I wish I could learn how to play music, but I know that takes hours of regular practice. Attaching it to my bike would let me learn while riding.

      1. Headphones are not an on/off deal, it is pretty easy to adjust volume and placement so that you can hear the traffic and the music at the same time. And depending on where he rides, bikes might be separated from cars altogether.

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