ericL wrote:pterm wrote:Excellent! Well done and thank you for sharing.
Do you know what the current consumption is and did you tried to power it off the Midi Out's pin 4 "5V" pin?
Your build looks very clean and well-made. --The only improvement I thought of was to try eliminating the external power feed (if possible).
Unless Nord has changed something, their MIDI out has not ever carried power. Way back when I used a Voce MIDI Drawbar with my NE2 via a MIDI Solutions box that would translate the conversation between boxes, I needed to use a separate power supply box for the MIDI Solutions box. Also, I had the Ocean Beach drawbar module in use with my NS2. The guy that built these incorporated a 9V battery inside the drawbars to accommodate the lack of power coming from the Nord. I wonder if this pitch / mod stick could be powered via 9V instead of separate external power?
There is a guy who built an entire polyphonic synthesizer the size of a midi connector that siphoned power from MIDI out. I really recommend the video he made. The 5ma current however is not enough to drive the Teensy 4 (which is way overkill for a project like this, but it was cheap and has USB MIDI support which made it easier to test the feasibility of this project). At a clock rate of 600Mhz the Teensy 4.0 draws around 100ma of current, but I underclocked it heavily for thermal reasons. The optocoupler, MIDI out and the 4 10k potentiometers also draw some current albeit very little. If that man can run a polyphonic synthesizer with 5ma of current it is probably possible, but I doubt this would be achievable with a Teensy or Arduino,
Stealing current from the Nord, if it even supplies it, also makes it impossible to use an optocoupler which is required by the midi standard (don't quote me on this, I'm don't hold a degree in electronic circuits). An optocoupler isolates the ground of the MIDI out sender to the MIDI in receiver and eliminates ground loops. The optocoupler
circuit I replicated is detailed hereIt currently runs off a 5v barrel plug. I thought of incorporating a chargeable battery or 9V battery and it certainly is possible, but the enclosure I have is too small to fit either one. The joystick assembly occupies the entire empty space on the last picture. I'm also prone to feature creep in my projects, so I wanted to start simple. I might redo this project later with a higher quality joystick, perhaps one the drone racing folks use or a replacement part of existing synths. Maybe even the famous Nord pitch stick, who knows.