[sdiy] Very cheap SPI pressure sensors.. anybody ??

[Ben Stuyts]

Has anybody ever tried pointing a video camera at the piano roll and do some real-time machine vision type of recognition? Would the resolution (i.e. timing) be good enough?

Ben


> On 19 Mar 2021, at 23:06, Didrik Madheden <nitro2k01 at gmail.com> wrote:
> 
> On Fri, 19 Mar 2021 at 22:29, Jean-Pierre Desrochers <jpdesroc at oricom.ca> wrote:
>> An optic based reader would look about like this:
>> [Image]
>> 
>> Notice the big horizontal LEDs bar over the row of holes in reading..
>> 
>> Not very nice..
> 
> The cable management could be nicer, but I would personally not mind.
> But I can see two problems:
> 1) It doesn't look original.
> 2) Even if you don't care about that, it obscures the currently played
> line, which might be aesthetically important.
> 
>> On the other hand a vacuum based reader would look like the original thing:
>> [Image]
> 
> Oh! That's something I didn't understand about the mechanism at first.
> I thought the vacuum was transmitted through the paper, so that you
> would have one "transmitting" side and one receiving side. Instead, it
> has constant pressure and relieves the vacuum pressure when a hole
> passes over.
> 
> So that gives me a different idea for a working principle based on
> light: reflection. No hole=light reflects back. Only one side of the
> paper has electronics. This could be done with either a visible LED
> (for an additional visualizer effect) or an IR LED (for
> authentic-looking operation). This method might be susceptible to
> light interference through the holes though... Probably not a good
> idea, just throwing ideas out there.
> 
> /Didrik
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