One of the ideas for this build made some of the precious controller pins reserved so they could potentially be connected to an external device for triggering notes. While keeping these pins from doing something useful, the serial input port was being ignored. Once it became apparent the IO pins were too valuable, the compromise was that input would have to come over MIDI, which would mean accommodating an incoming MIDI signal, which had not been done by me before.
An image search for "MIDI input schematic" will turn up a variety of circuits and most of them will work. Many of them feature an optocoupler, a part that was in stock. In front of the optocoupler was an ordinary diode, but an LED was more convenient. This circuit was assembled in temporary dead-bug fashion to test it.
The circuit failed, but the LED would light up when the leads were reversed, so power was getting where it was supposed to be, but nothing was reaching the controller.
Some hunting with a continuity meter revealed that the wiring running to input 19, the serial1 receiving pin, was terminated to an unconnected via. I forgot that this was done on purpose to place the MIDI input circuit on the controller board where it would eventually be bridged to the pin. That is what I get for planning but forgetting.
The rest of the posts for this project have been arranged by date.
First time here?
Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6
Disclaimer for http://24hourengineer.blogspot.com and 24HourEngineer.com
This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.
All information in this blog, or linked by this blog, is not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.
All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.
Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim property or assets based on their post.
This blog, including pictures and text, is copyright to Brian McEvoy.
2019-04-13
MIDI in and MIDI out ports
An image search for "MIDI input schematic" will turn up a variety of circuits and most of them will work. Many of them feature an optocoupler, a part that was in stock. In front of the optocoupler was an ordinary diode, but an LED was more convenient. This circuit was assembled in temporary dead-bug fashion to test it.
An attempt at an optocoupled circuit
The circuit failed, but the LED would light up when the leads were reversed, so power was getting where it was supposed to be, but nothing was reaching the controller.
Receiving signal, loud and clear
Some hunting with a continuity meter revealed that the wiring running to input 19, the serial1 receiving pin, was terminated to an unconnected via. I forgot that this was done on purpose to place the MIDI input circuit on the controller board where it would eventually be bridged to the pin. That is what I get for planning but forgetting.
Unjumpered wire
The rest of the posts for this project have been arranged by date.
First time here?
Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5
Completed projects from year 6
Disclaimer for http://24hourengineer.blogspot.com and 24HourEngineer.com
This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.
All information in this blog, or linked by this blog, is not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.
All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by Brian McEvoy, cannot be used to claim property or assets.
Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim property or assets based on their post.
This blog, including pictures and text, is copyright to Brian McEvoy.
2019-04-13
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