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    Teensyduino crashes constantly on Catalina.

    I downloaded Teensyduino from the link above and ran some tests on Catalina 10.15.4. Multiple monitors, mouse scroll wheel vs trackpad, scrolling, resizing, all behaved normally with no crashes.
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    Teensy and LEDs

    You could use transistors to switch them, that way the Teensy is just driving the transistor and not the LED. Google Arduino You could also use something like a 74hc245, there's several examples of an Arduino controlling LEDs with those.
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    In need of complete Teensy 4.1 dimensions

    USB (5 pins in a row) spacing is 0.1 inch pitch Ethernet (2 rows of 3) spacing is 2mm pitch
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    [posted] music string winding device

    Very cool and interesting project!
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    CS Pins expander 74HC154 or MPC23S17 ?

    For what you've told us I'd say there's no practical advantage of one over the other. Even something hybrid like one 74hc154 controlling 16 of the pots and teensy pins controlling the remaining 9 would be pretty simple to handle with a case statement or handful of if/thens.
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    method to addd a transistor to 4.0 or 3.2 to boost a pin output to 5v

    A1) (NPN), (PNP) just replace the 12V with 5V and the motor/buzzer with the controller. You don't need the diode from the first example. A2)...
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    AdaFruit Medium 16x32 RGB LED matrix panel

    I don't think you can connect it directly; the board wants 5V signals and the T4 runs at 3.3V. You'd need something like this with some pin modifications here...
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    Teensy 3.2 external power source

    Could you try a different cable? Some USB cables are charging only, they're connected on the power pins/wires. and not the data pins/wires.
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    Teensy 4.1 Beta Test

    Hi @KurtE, thanks for the pinout card (#94). I think I've found an error. You've got digital pins 40 & 41 on the same GPIO 1.21. I believe 40 is 1.20 and 41 is 1.21
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    Teensy 4.1 Beta Test

    My mistake. Thanks for the clarification.
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    Teensy 4.1 Beta Test

    In response to #76 (and AlanK's reply #78) I connected 16 LEDs to pins 19, 18, 14, 15, 40, 41, 17, 16, 22, 23, 20, 21, 38, 39, 26, 27 via a pair of 74hct245's and everything works as expected. int pins[16] = {19, 18, 14, 15, 40, 41, 17, 16, 22, 23, 20, 21, 38, 39, 26, 27}; void setup() {...
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    Accidentally connected +12V to Teensy 3.2 for several seconds; still seems to work?

    The 3.3V for the Teensy 3.2 comes from an LP38691 regulator (schematic at, and the datasheet for it says it can take up to 10V. So yes you got lucky you caught it fast enough to not fry it but not impossibly lucky.
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    Teensy 4.0 System Tick Rate?

    My understanding is the tick rate how often the OS wakes up to do housekeeping or switch tasks so it would be 1/F_CPU, do you have a different definition? Are you looking for something like IntervalTimer ( ?
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    Using Teensy as a relay between two Raspberry Pis

    The fastest way I could think of would be to connect one of the RPis to the Teensy directly via USB serial and the other by hardware serial, but I'm mostly wondering if this is an XY the top of my head I can't think of any case where I'd do communications between two RPis with an...
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    Connecting together multiple boards

    How about a Teensy reading the analog inputs of 4 of these over I2C
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    Teensy 4.0 without shield

    No Teensy 4 does not have a DAC, you'll need to use one of the 3.x boards or additional chips
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    Teensy 4.x

    Most likely.
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    LED matrix questions

    You send 2 lines of data with every row so for x32 boards it's 16 iterations. This explains it better than I can. As far as the update rate goes -- let's say you want 8 bits of color resolution and you want 100 update per second so it's not...
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    LED matrix questions

    For the most part you're on the right track but I'm not sure about 10 boards across. If you get the 64x32 boards that's 640 pixels that need to be clocked out * 16 rows * at least 50-60 times per second so it's not too flickery * bit depth. I think the library supports up to 128 pixels across...
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    How many rgb LEDs from USB power with tlc5940?

    I didn't see a specific current draw from your link but in general you can assume about 20mA per individual LED, or 60mA per package. If you're talking about USB power from a device like a computer you're limited to 500mA. Some ports on some computers can do more, and very old computers with...
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    New to Teensy

    Are you looking to just buy 4 of the Cherry switches and build your own enclosure? If so, you'd just connect those 4 switches to 4 inputs pins on the Teensy. There's plenty of examples on how to wire and read a switch, like here: Once you can read the...
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    Teensy 3.2 external power 9Volt problem

    Try disconnecting the Teensy from all other wires and connections with only the USB cable from the computer to the board, then try uploading something basic like the Blink sketch. If it doesn't work try pressing the Program button. If none of that works then yes my guess is the board is fried.
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    Teensy 3.2 external power 9Volt problem

    You can't really use resistor voltage dividers to supply current to anything that takes a nontrivial load. From This link from StackExchange goes over some alternatives...
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    Looking to buy a reflow oven

    Your last link (product 251) is the one I used (along with the amplifier # 13266). I touch the thermocouple tip to the surface of a board when I run a reflow. As for calibration, I have an infrared thermometer but it doesn't give very accurate measurements through the oven glass. I ended up...
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    Looking to buy a reflow oven

    @jwatte - thanks for the info on MacroFab, I had not seen them before. @linuxgeek - yes that relay should be fine. Regarding your question on MacroFab part sourcing, from their FAQ ( it looks like they will use Digikey or Mouser to get parts they don't stock...
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    Looking to buy a reflow oven

    No experience with the oven on Amazon, but the reviews make it seem reasonable. If I had to start from scratch I would consider it; people who have done the mods seem happy with performance. As for controllers, this one came out shortly after I built mine (several years ago) and it's still for...
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    LED coffee table with Teensy 3.2+OctoWS -- animations while headless? How?

    Sorry, I just realized I didn't answer your #1 question very well. For 10x12 you're going to have to do some cable path management either way. If you go with a single pin and FastLED you can snake the data line back and forth easily, then map physical address to logical location. If you go...
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    LED coffee table with Teensy 3.2+OctoWS -- animations while headless? How?

    For 120 LEDs I think you'd be able to manage 60fps with either FastLED or OctoWS2811. Even if you go with FastLED and only use 1 pin you'll need something to level shift the Teensy pin to 5V so using the OctoWS2811 adapter will save you from having to make your own circuit for that. FastLED...
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    PCB Assembly

    I can't help with an assembler recommendation, but Osh Park ( is what a lot of us use for low volume boards. I've used them for years with zero issues.
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    Video: FastLED simplex noise modulated by itself

    Thanks! I will play with this as soon as possible.
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    Video: FastLED simplex noise modulated by itself

    This looks great! Is your code posted anywhere?
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    Connecting a Teensy with RPi

    You can connect the RPi's ground & UART pins to the Teensy's and send the data serially, something like RPI Teensy 6 (gnd) -> GND 8 (TX) -> 0 (RX) 10 (RX) -> 1 (TX) By happy coincidence those 3 RPi pins, in that order, plug directly in to the first 3 pins of a Teensy (all of...
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    Teensy 3.2 LED spazzing

    Yes, all grounds need to be connected together. [edit - fixed quote]
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    Make Teensy and Raspberri Pi communicate? (without effort for the Teensy)

    The RPi doesn't have access to the Teensy's RAM to be able to do DMA. You'd have to use some transport mechanism like I2C or SPI to send the bits to one of the Teensy's interfaces so you could use DMA, and I can't see a scenario where rolling your own hardware + software to send 2 bytes of data...
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    Make Teensy and Raspberri Pi communicate? (without effort for the Teensy)

    I came here to say pretty much what KurtE said. You can easily expand the serial buffer RAM on both sides if necessary, and/or use flow control with GPIO pins and something like attachInterrupt() to monitor that on the Teensy side for immediate results. Sending 10+ bits of data is no problem at...
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    Make Teensy and Raspberri Pi communicate? (without effort for the Teensy)

    How about plug the Teensy into a RPi USB port and use serial communication to send the data back and forth.
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    Teensy 3.2 LED spazzing

    How do you have the Teensy connected to the LEDs? Are you using a 3.3->5V level shifter?
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    How to quickly toggle 38kHz signal?

    You could set up an IntervalTimer and flip the state IntervalTimer myTimer; void setup(void) { myTimer.begin(Flipper, 10000); // flip the state 100 times per second ... } void Flipper(void) { static int state=0; if (state==0) { state=1; analogWrite(myPin...
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    How to 'paint' a circle on a LED matrix

    For something small like a 5x5 matrix I'd probably just precompute the pixels and save it in an array, but if you really want to do it programmatically you can do it with Bresenham's algorithm (
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    FFT with Teensy 3.2 but no Audio Board

    Yes you can do this, you just need a microphone or line in circuit to an analog pin. The audio library has a reference circuit to convert an input signal to the 0 - 1.2V needed.
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    What are people using for WiFi?

    I've been using the Particle Photon ( as the TCP/IP side of a few projects. The Photon does the web / user interface, the Teensy 3.x's handle the grunt work, and they talk to each other over hardware serial. I personally only use Particle's cloud stuff...
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    Teensy Microphone Module

    The big advantage your board has is it's already biased to 0.6V instead of 1/2 VCC like the other boards, so there's no need to do shenanigans like this to connect use it: I know there's a...
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    OCTOWS2811 and DOTSTAR problems

    I doubt it's an issue with the wiring, especially from the 245 chip to the RJ45 connector. You won't be able to use the PJRC OctoWS2811 library; it's written for WS2812 LEDs (what Adafruit calls "Neopixel"). You can rule out voltage issues by limiting the maximum brightness on the APA102s...
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    reading variable in web server get reply

    If I'm understanding you correctly, you get a string like "/?text1=15" and you need to parse the value 15 into an integer variable? I don't really ever use the String class but something like this should work, or at least get you pointed in the right direction. int pos =...
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    APA102 investigation. Different libraries, shared clock pin, etc.

    In the library APA102.h transfer() function replace the digitalWrite() statements with digitalWriteFast(), and be sure in your code your data pin and clock pins are constants or defines. This will speed up the pin twiddling as much as possible; in fact it might make them so fast you might need...
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    Teensy 3.6 with Electret Microphone (MAX914) with auto gain

    A few things. First, in a quiet environment your Teensy should read around 390: the DC bias of the module is 1.25 Volts and your Teensy is running at 3.3 Volts; 1.25 / 3.3 * 1024 = 388. It will never be exact because of line power noise, random fluctuations, etc. but it should be close to that...
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    Teensy 3.6 with Electret Microphone (MAX914) with auto gain

    Back up to make sure your hardware is working. Do something really simple like this: void setup(void) { Serial.begin(9600); } void loop(void) { Serial.println(analogRead(A2)); delay(10); } In a quiet room the number should stay about the same. Loud noises should make it move more. If that's...
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    Teensy Microphone Module

    If there is then it's not specific to your design. Just a bit ago I tested your module with the Adafruit MAX9814 board and Adafruit's is definitely more noisy. My camera doesn't like the lights in my office so tomorrow when there's sunlight I'll make a side-by-side comparison video. It also...
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    Teensy Microphone Module

    Here's some videos of the microphone module hooked up to a T3.6 driving the 64x32 APA102 matrix, running the OctoWS2811 SpectrumAnalyzer example modified for the APA102s. Frequency sweep: Short music clip: Everything's looking great! More tomorrow.