Posted by: sebion | November 24, 2011

A Tale of Distant Lands

Now that I found some time to continue my work on my optically sensed piano (I think I did a great job improving the playablilty of my ivory) I thought it’s time to show you a new recording along with my report – so let’s start with the music. This time I choose ‘A Tale of Distant Lands’ aka ‘Von fremden Ländern und Menschen’ by Robert Schumann:

As you already know I’ve had a lot of trouble to make the keyboard behave equally for each key. The last weeks I’ve spent a lot of time developing automatic and manual calibration methods for my sensor system trying to adapt the virtual physical parameters. These attempts had a little success only with the reflection tags being handmade of paper and glued to the keys without any capability of adjustment. So I decided to remove the quick and dirty ‘paperwork’ and use a more reliable and adjustable  solution:

I simply cut little sheets of steel and melted them into the keys and glued sheets of paper on them:

When that was done I bent each metal sheet so that the sensor saturation degree at the key bottoming was equal for each key. I did this using a selected weight, which I put on each key to measure the sensor signal at the depressed key state.

When Everything was done I got an amazing equal weighted keyboard, but there was still a problem I’ve ever had with that stupid DP50 Keyboard: The keys tend to bump a lot when they reach their relaxed position after a key is released. I first tried to get rid of this behavior  by adding rubber bands (a cheap spare for springs to test things) to the keys. I’ve to admit it helped to some extent, but it didn’t really solve the problem: It only made the keys come up faster and bump faster. The final solution here was to add a felt stop with very thick and soft felt to the hammer’s relaxed position:

I also decided to put some additional weights to the hammers to get a more realistic feeling out of the keyboard. Maybe the keyboard is a little hard now, but I think it serves very good playablity. I guess it will need some weeks of testing till I can tell if it shall stay this way or not:

Finally I reassembled the entire piano in order to use the internal speakers for audio output again and to compare the old 2-switch sensors with my sensor bar:

As you can see: Now It’s time to have a walk with my cute little dog 🙂

The next time I might be reporting about my attempts to add polyphonic aftertouch, so stay tuned 😉



  1. Nice!

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