MIDI↔USB adapters tested the hardware, but they indicated that all the devices were outputting reliable signals. Granted, since it was a mature protocol, there could be some error correction built into the adapters for when they have to interface with cheap MIDI toys. An oscilloscope allowed me to look at the waveforms directly. The signal from the first version served as the starting point since it had usable output MIDI longer than anything in this project.
It was not necessary to decode the output on the oscilloscope yet, the vital thing was to see that the signals were not wildly different. MIDI from the Little Drummer Bot looked similar in terms of how long the pulses lasted, but there seemed to be more oscillations.
An Arduino Mini Pro received programming to output the kick drum at a known velocity for comparison with the Little Drummer Bot. On screen, they seemed to be the same, even though the bare Arduino used the ground as a reference while the drum machine used Vcc as a reference. This can be seen in the pictures because the Mini Pro trace starts and ends above the 0V line.
Nothing in the code seemed suspicious, so all the extra hardware was removed. The bare Arduino transmit pin connected right to the receiving pin of the Arduino MEGA and MIDI was sent across at full speed. For once, it worked! My best hypothesis was that the optocouplers were too slow to keep up with 31,250 bits per second, but 18,000 was under the threshold. New optocouplers were ordered,, but it may be safe to tap right onto the data pins.
This proved the trouble with data transmission and reception was not the fault of the Little Drummer Bot so LittleDB is complete!
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.
2019-04-27
Measuring data from the old EWC
It was not necessary to decode the output on the oscilloscope yet, the vital thing was to see that the signals were not wildly different. MIDI from the Little Drummer Bot looked similar in terms of how long the pulses lasted, but there seemed to be more oscillations.
Measuring note 37 from LittleDB
An Arduino Mini Pro received programming to output the kick drum at a known velocity for comparison with the Little Drummer Bot. On screen, they seemed to be the same, even though the bare Arduino used the ground as a reference while the drum machine used Vcc as a reference. This can be seen in the pictures because the Mini Pro trace starts and ends above the 0V line.
Measuring note 37 from a barebones sketch
Nothing in the code seemed suspicious, so all the extra hardware was removed. The bare Arduino transmit pin connected right to the receiving pin of the Arduino MEGA and MIDI was sent across at full speed. For once, it worked! My best hypothesis was that the optocouplers were too slow to keep up with 31,250 bits per second, but 18,000 was under the threshold. New optocouplers were ordered,, but it may be safe to tap right onto the data pins.
Rx and Tx pins directly connected
This proved the trouble with data transmission and reception was not the fault of the Little Drummer Bot so LittleDB is complete!
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.
2019-04-27
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