Sander

Analog scanning of manuals: Is it fast enough?

4 posts in this topic

I've started a midification project of organ manuals to hook up to organ simulation software (Hauptwerk). As interface I'd like to use a reflective opto switch. I'm currently testing this with the Vishay CNY70. When pressing a key, the amount of refective light and thus the output resistivity / voltage changes. To scan the output I have two options:

 

1) Scan it with DIN and tune the correct voltage for the moment it switches, perhaps with some potmeters to tune the LED or output voltage.

 

2) Use AIN to scan the acual position of the key and set a threshold for each key on when to switch. This enables full control over the key, and for example enables a different position of NOTE ON and NOTE OFF. I'm wondering however if this would response fast enough to play music.

 

 I still have some old parts (MIOS V2 mainboard) for testing, but could also get a newer version.

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In MIOS8, each analog conversion will take 200 uS, accordingly 64 inputs can be scanned within 12.8 mS

 

This might be sufficient for an organ keyboard, but you've to try it out.

 

MIOS32 in conjunction with the MBHP_AINSER64 module and the MBNG firmware won't be much faster (ca. 10 mS for 64 inputs), because the driver isn't optimized for higher speed. In theory a faster conversion would be possible, but this would require a different firmware.

 

Best Regards, Thorsten.

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12.8 mS sounds a bit slow, but I'll test it out. I assume DIN is a lot faster. Is it easy to change the MBNG firmware for an experienced programmer or are there really fundamental limitations?

 

Can you send me instructions to update my old PIC 18F452 to the latest MIOS version? The current bootloader was loaded 9 years ago and doesn't work with the new MIOS.

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Hi, to make use of the new MIOS32 you have to get a new LPC17 core module.

 

my regards

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