DIY piano sensors

RIP · 2021-12-14T22:14:39+00:00

This is mostly a question for @CyberGene but I think making it public could help others, in the same way that your pioneer project inspired many followers (including myself) I am arriving at the sensor stage of my project and I decided to test a few of them. @CyberGene Pretty much every DIY these days is using the CNY70 sensor which your groundbreaking project selected. I've found your posts on a variety of forums discussing the options you were considering at the time, but I did not find any of the class below. For example, the same manufacturer of the CNY70 sells many more sophisticated sensors, such as this one which goes "for peanuts". For less than 3 dollars you get one surface mount chip which includes: LED emitter (like the CNY70) Fototransistor receiver (CNY70) 16-bit ADC with offset compensation for temperature drift and ambient light influence I2C bus with high speed mode other stuff less important brews yourself a coffee and serves it in a golden cup From a cursory look, it might be possible to just put a bunch of these chips on the same I2C bus, and with a simple I2C controller get everything one needs for a DIY piano! Just the sensors you want (176+3 in my case for note on, off and pedals) and a single other board. No potentiometers. Free, industrial grade ADC and bus just there waiting to be used, without the need for one to design and implement them. Back of the envelope math indicate that the bus speed (3.4MHz) and capacity (1008 devices) is more than adequate for the amount of traffic expected, and any GHz grade controller should have enough horsepower to handle all the incoming digital data. But even if not, splitting the keyboard in a few sections with a few controllers would still be easier than all the other approaches I've seen. I'm really surprised nobody else mentioned these, so I must be missing something? Note that the one I picked is pretty much just a random one among many similar ones Vishay makes -- and I have not looked at other manufacturers yet (but I know that Evec makes the EAITRCA6 which is direct competitor of the CNY70, and the main one which I intended to test side-by-side when I accidentally found these with ADC and I2C integrated in the same die) So the question is: back in the day, did you evaluate this category of sensors and discarded them for some reasons which at a cursory glance I am missing?

RIP

xooorx The Cybrid, the VPC1, any of the 2/3 squidgy switch based systems, anything with a light gate waiting for a slot to pass through it... none of these systems are measuring velocity (distance/unit-time) directly. They are all measuring colevity (time/unit-distance) and then calculating a velocity by taking the reciprocal of the measured colevity.

(Yes, OK, "colevity" is a word I just made up, but it's still the thing that all these systems are measuring).

@xooorx you are not the same person as @Gruust on PTQ's site, are you? Reason is, somewhat I thought you were, but if you aren't I should ping that other person to come at least lurk (if not contribute) here. See e.g. https://forum.modartt.com/viewtopic.php?id=8956

xooorx

RIP @xooorx you are not the same person as @Gruust on PTQ's site, are you?

No, I'm "xooorx" on here, on PTQ, and on PW.

RIP

xooorx delvento @xooorx you are not the same person as @Gruust on PTQ's site, are you?

No, I'm "xooorx" on here, on PTQ, and on PW.

Thanks for confirming. I'll reach out to that person then. Meanwhile, you (and others) might want to lurk or chime in the conversation at https://pianoclack.com/forum/d/289-scanning-speed-and-velocity-mapping-of-cybrid