u/IfIWereABird

Hi, hobbyist saxophonist here! Been playing since elementary school, and am in a few bands. Maybe this is a better question for r/musicians or the likes, but I figure many of us are in the field of Jazz and know something of solos.

I see people shredding all the time up and down arpeggios with modal modulation and crazy music theory, and I get that takes fine-tuned practice of patterns and scales and transcriptions. But I have no formal training past high school and playing.

I'm wondering, how much of that is repetition of that solo in practice to fine tune it and hone in for a particular composition (i.e. plays same on stage as in practice), and how much of that is done on the fly?

I tend to do a mix of both, fine tuning bits and pieces, but ultimately my "words" come out different each time. But then again, I cannot figure out how to get my fingers to move that fast, even 12 years playing since an active lesson.

My babies for the algorithm.

Hi all, new here. Working on a FOC motor controls project for some legs on my robot crab I've been designing for the better part of a year. I have looked into the ODrive Micro, and with its hefty price tag I'm not sure it's the right fit for my use case - I need a staggering 18 of them (3 per leg, 6 legs lol), and at nearly 100 buckaroos a pop PLUS TARIFFS that's more than I'm willing to spend. Not to mention, the Micro can only handle 7 amps peak, and I have motors that can pull 15 amps continuously and I'd like to be able to make full use of that range.

So I turned to ESP32. I purchased this cheap crappy board from AliBaba that claimed it could drive at 20 amps, which is PERFECT! Unfortunately, there is NO documentation, and that should have been the first red flag. I got the board, and turns out, yes, the FETs can in fact drive 20 amps, but the current sense circuitry consists a 10mΩ shunt resistor and a current sense amp of gain 50 whose output feeds into an ADC pin on the ESP32. Doing the math, it comes out to 6.6 amps of current measurement... so plus or minus 3.3 amps. That makes it even worse than the Micro for my use case. Well, OP, I hear you say, why not just replace the amp or shunt resistor or both? Well, I think they must not have had a clue what they were doing when they designed the board, because the bias voltage according to the amp's datasheet should be half the input voltage (3.3V) but I measured it at 400 millivolts (i.e. 0 current = 400 millivolts). A simple replacement would not refactor the board layout to fix whatever crud is going on. So I'm back to square one.

So, why I'm here, I'm looking into designing my own PCB. I know it's a hefty task, but it's made worse by the fact that the chip I'm interested in acquiring, an ESP32-P4, doesn't seem to be something I can buy on the internet. On top of that, I can't find any libraries for the chip's footprint to stick into Fusion. Maybe I'm just looking in the wrong place. What I hope to hear from the experienced folks here is whether this is the right chip for me in the first place. I don't need WiFi and Bluetooth capability, and the P4 seems to not offer that. I would like to be able to run my control loop as fast as possible, and the P4's clock speed tops any other ESP32 I've seen, but I think I could get away with the typical 240 MHz that the S3 offers. Of course, a MC PCB may end up being quite dense, so I am hoping to find an ESP32 variant which requires minimal supporting hardware so that my PCB can be as small as humanly possible. I have read that the S3 also offers a MCPWM interface as well, which could be useful for reducing board space.

Secondarily, if anyone has any idea where I could find libraries for ESP32 chips, that would be much appreciated.

Pic of the arm for the algo.

TLDR: I need recommendations on an ESP32 chip to design a compact, high-power FOC Motor Controller around.

On Soloing

Need Chip Suggestions for a Motor Controller Design