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Thanks, MarkT. This is my first board of this complexity and I'm still learning while doing it. The weird thing is that it all works absolutely fine while powered from USB. No audio noise, no hot spots on the board or on any components. The tracks are thin, yes, but the total current I've...

A sad update. I've found Adafruit's diagram for the 1000C board and decided to "reflow" it onto my board. Got all of the specified parts, all in proper footprints, and made a new board with the charger on it. Plugged in the battery and connected for charging. Looks good, but gets a little hot...

I want to load a few instrument samples (flute, piano, drums, etc.), but run out of memory quickly. Is there a way to "move" memory from "Program" to the "other". Now its usage is 4% vs. 65%. To get to 65% from 94%, I had to limit my instruments to a very few. And I don't want to add the memory...

Thanks for checking my posts, defragster. I didn't delete them. I tried to fix some typos in them and the moment I started to type they just disappeared, so I had to do it again. Doesn't matter. But the Adafruit 1000C works fine for me. I'll use it, even though it's much more complex and...

Thanks, KD5RXT. I'm just going to see if the board works, which it does, as you say. Them I'm going to "reflow" it to my absolutely awesome guitar/keyboard/composer board. 8 hours is amazing, but I'm afraid the battery will be too big. I need my whole thing to be small enough to be attached to a...

Thanks guys. Just got the 1000C at DigiKey. Looks twice as complex as what I had, but I hope it works. Will let you know. This is so strange. This is the third time I'm posting a reply and they just keep disappearing.

Turns out that it's my battery charger. When I use power from the PC USB, the USB host works fine. As soon as I enable the battery charger, the USB host never puts out the 5V. I'm sure the charger limits the current going to Teensy and there is not enough of it for the USB host and the keyboard...

Silly me, totally forgot about it. Looked it up and see the resistors suggested ranging from 1K to 220K. What resistors would be good for the Teensy Audio Board? I guess 220K will loose more signal and 1K will add too much crossover, no?

How to combine mono and stereo line inputs I'm making a guitar effect "pedal" based on Teensy 4.1 and the Audio Board. It also has a Line Input, for "play along". The problem is that the guitar has only one channel, but I have to split one channel into 2 separate preamps only not to...

Just for a comparison, I've ordered 5 PCB's at JLCPCB.com, in China, ($2 for all 5) on Saturday. They were made in 2 days and shipped via DHL on Sunday night, for $17. I got them in New York on Wednesday afternoon. I think it's absolutely amazing. 5 prototype PCB's, $20 for everything, in under...

Just noticed that the library for it was updated 4 months ago: https://github.com/adafruit/Adafruit_CAP1188_Library Want to give it a try? I can do it only in about a week or two.

Thanks for clarifying, Paul. If this is how it works, that's fine. It just makes it difficult to understand what's happening sometimes. The confusing part was that the test sketch seemed to work fine. I've added another serial "printf" at the end of "setup", to make sure that it all goes...

New findings. It has to do with the Teensy ports, the way Arduino sees them. This morning, after a PC reboot, I plugged in the bare Teensy 4.1 with nothing on it. The port name that Arduino showed was not COM, but like "USB..." and a longer string after that, not "COM..." Loaded the test, see...

What Teensyduino you guys are using? I got the latest a couple of days ago: 1.53 with Arduino 1.8.13 I just got a new and untouched Teensy 4.1, connected the power, loaded the test, see "USB Host Testing", but no +5V on the USB host. I do see +3.3V on Teensy, in case you wonder about my...

I ran this example, which worked fine with Teensy 4.0: C:\Program Files (x86)\Arduino\hardware\teensy\avr\libraries\USBHost_t36\examples\Test\Test No response, no 5V.

I never got anything back from Adafruit on this. It kind of worked with the delay suggested above, but overall the sensors were not usable for me - no reliable response to fast touch/release. I think I'll look for another sensor. Will let you know.

Thanks everybody for your help and advises. Well, turns out that all I needed was to turn up the amplification on my guitar preamp. I put a couple of potentiometers for that and made sure that my oscilloscope shows around 3V amplitude on the preamp output. Then I could turn down the audio input...

I have the USB host GND connected to the common GND. Is that the problem? I use my own PCB. Should I connect USB GND to the USB connector only? The funny thing is that there is +5V between "5V" on the USB and "3.3V" pin, not the GND. There is not really much documentation on Teensy 4.1. Or am I...

Thanks for the video, boxxofrobots. I do have a bunch of those capacitors, maybe not enough or not in the right places. Will experiment with that. Just not sure about the capacity and the placements.

Hi MatrixRat, Tried to lookup "sharp edge decoupling", didn't see anything relevant. Can you clarify please?

This is my board, with the ground highlighted. Just don't see how I can improve much there, other than do some copper fill here and there, probably on the green side. The whole thing is 6x8 cm. All audio stuff is at the upper left corner.

Thanks boxxofrobots, I'll try the star grounding in my next version of PCB. Just ordered this one from JLCPCB yesterday. On this version, I'll try adding components one by one and see which one contributes to the noise the most. I have tons of things on a 8x10 cm board. Everything is very close...

@jonr. My thingy is battery-powered. Would really hate to have 2 separate batteries, but I'll give it a try, just for the heck of it. The ground will still be common, though.

Thanks @ETMoody3 I figured out the screen noise, it's quite "obvious": the noise is clearly related with what's happening on the screen. I'll try to find a way to turn all SPI communications with it until necessary, only for changing settings. I'll keep it off at other times, to minimize the...

I make a Teensy 4.1 based sound effects processor and have my guitar preamp very close to the Teensy and audio processor. I can hear some digital noise on the guitar input and want to minimize it. I try to separate all analog stuff from the digital and put all the good capacitors, but wonder...

@sockmonkey Didn't touch the library and not going to. I just need to get by to make my guitar and keyboard effects thingy to work and start making it. Maybe later I'll take a look at the whole audio library and see how it works. If you find something there we can fix, please share.

My answer in two words: forget it. I've spent maybe a week trying to create/delete effects and connections between them dynamically and gave up. It works for 2 or 3 times, then the poor little thing (Teensy) pretends it's not there. Memory leaks, stray pointers? Who cares. It just doesn't work...

As a very responsible citizen, I go further. I not only cover with mask, but also plug some orifices to protect the others from an accidental exhaust. There is still so much unknown about the spread of the virus... Damn, all of this drives me nuts!!! Where is my Teensy 4.1? All I need to know...

Jim, man, this is so sad. Ever heard of a donkey named Eeyore? Put it on GitHub and post a link to it here and on arduino.cc forum. This is what I'm going to do. Just make your stuff user friendly and document it so that people can use it quickly. This is what we all are here for. I just...

Thanks Matrix, This is pretty much what I have now, too. I also have buttons and hope to do the scroll list this week. Also a text box with on-screen keyboard sometime soon. I have the code on GitHub, but it's just too ugly to share yet.

Thanks Brian, This does look smooth. The problem is that this kind of libraries probably depend on support for specific displays. I'm saving all the good things people suggest here and will take a look if I need more than I already have. I think I have a good start for what I need. Will post...

Thanks Jim, I've started my own little thing here, just what I need, which is not much. I'm half-way done. Looks like it may be longer to accommodate other people's things than make your own. Hope do be done in a month or two with the whole guitar/synth effects "pedal", then I'll share the...

Yes, it does look very impressive. Thank you for pointing this out.

Any way will work. You define the connecting points when you create the connection and can only connect/disconnect later. You cannot change the points of an existing connection. If you delete/create a new connection each time, like in my example, you can define new points and connect. Spend a...

Use the low-temp paste. Takes 10 seconds to heat up the chip, remove it, wipe off the extra paste, move the chip around to make the paste adhere to the pads only and put it back on. I've done it lots of times and never damaged anything. The temperature is 130C, a little more than a boiling...

I just do "new AudioConnection(...), like you show. You don't have to call ->connect(). If you don't need it, just "delete". It disconnects. Having them "pre-made" is a pain, as you need to give each a new name. I just have an std::list of connections, add all of them to connect things, then...

Thanks @palmerr, I'm pretty good with the heat gun and low-temp paste. The trick is to put a little paste all around, then heat up the whole chip and move it around the pad a little. Then the paste spread evenly and the chip "snaps" into place, with each pad getting sucked into its place by...

Just found this: https://www.mouser.in/datasheet/2/256/DS4420-1095341.pdf Looks like what I need. $3.22 on DigiKey, not bad: https://www.digikey.com/product-detail/en/maxim-integrated/DS4420N/DS4420N-ND/1769257 I think I'll try it.

I want to add a programmable gain amplifier to my Teensy-based guitar "pedal", so that I can use guitars with different pickup levels. I already have the buffer with gain 1, so I'll put the amp right after it. Should be low-noise and 3.3V power. And I need it to be controlled via SPI or UART...

I need to add a user interface to my Teensy 4 with ILI9341 touchscreen. Looking for common things like edit boxes, scroll lists, on-screen keyboard, some kind of menu selectors, etc. Can do it from scratch, of course, but a jump start will be good. Doesn't have to be fancy, just functional and...

Got this: https://learn.adafruit.com/adafruit-airlift-featherwing-esp32-wifi-co-processor-featherwing/overview Giving up after a few hours. Getting "Communication with WiFi module failed!" in C:\Users\Homer\Documents\Arduino\libraries\WiFiNINA-master\examples\ScanNetworks\ScanNetworks.ino Had to...

Thanks @prickle. Those little invisible to me things would be killing me. Never in my life I'd figure out that the damn thing doesn't work just because I need 100 Ohm resistor here or there. Well, I'm sure that the good people at Adafruit are packing my 2 ESP32's. Will let you know how it goes.

I think I'll try what @MichaelMeissner suggested. I didn't know that ESP32 had both WiFi and Bluetooth. I'll get this: https://learn.adafruit.com/adafruit-airlift-featherwing-esp32-wifi-co-processor-featherwing/arduino It mentions Teensy pins there, hope it works. There is no mentioning of...

Thanks guys. I found this: http://www.digikey.com/product-detail/en/espressif-systems/ESP-WROOM-02/1904-1009-1-ND/8544304 It's $2.70, which is important because I want to sell my "super awesome sound processor" and keep the cost low. And it looks like it has all what's needed. If I get it...

I got the schema from here: https://blog.zakkemble.net/a-lithium-battery-charger-with-load-sharing/ The battery is charging at 100ma. I checked it using the jumpers for this purpose. The diod gets a little hot, but not too much. The problem is that the battery has 3.8V on it, but I get only...

Ok, thanks. I guess I'll just connect it and see how it goes. It it works, I may ditch the Bluetooth in favor of WiFi.

I did search this forum for this, but didn't see any definitive guide or results. Looks like for a few dollars more I can add a WiFi to my setup. If anybody has it working with Teensy 4.0, please share your experience: your diagram, libraries, power consumption, noise interference, general...

It works with the modified example I've posted on 10-06-2019, 07:19 PM above. One thing I've noticed is that you have "TFT_RST 8". Don't know if there is a point in this, as it has to be on +3.3V always. Or you need to have pin 8 on. Also, when I had the new audio shield connected as well and...

Well, the "flat-baking" of Teensy worked the first time and that's it. Tried 2 more time and wold get shorts all the time. It's hard to control the paste between the boards. Gave up on that, ordered the butchered "castellated" board, soldered everything and it all works now. Event the SD card...

I just tested my PDB's audio part, which is a "reflow" of Paul's Audio Board. The Guitar sketch works (synthesis), line input, phones, lien out work. The microphone works, but the sound is like the "phaser" guitar effect, like it's going though a long paper tube, like "bouncy" sound. Does...