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  1. J

    Completed Project: Front of House LED lighting

    Nicely done. I appreciate the detail you show. I was just talking about this with a friend of mine. Do you have video or other pictures of the RGB action?
  2. J

    2Hz analogWriteFrequency on Teensy 3.1

    +1. I, perhaps obviously, support this addition!
  3. J

    2Hz analogWriteFrequency on Teensy 3.1

    I don't think so, only because the code here doesn't include the low-frequency handling:
  4. J

    Need an example for RPM Measure with freqMeasure zero method

    maybe if U Think about it First then ppl will b moar willing to help. Give it a try and post what you come up with after reading the documentation available for elapsedMillis
  5. J

    Noob ? Can I really use both sides of my Teensy 3.x at once ?

    Any through hole is obviously the same front/back. There are additional surface pads on the back that offer additional signals. There are a few ways to connect to them. The easiest way seems to be to buy a circuit board as have been designed and posted here by a couple people, which you can...
  6. J

    Possibility of DIY to create midi for organ stop rail

    Seems to me that a Teensy is a great way for you to further your goals. The programming language is the same as Arduino, with a few additions. That is because Paul, the creator of Teensy, has built an extension to the Arduino environment to allow it to be used to program Teensy. That extension...
  7. J

    4-20ma output into teensy 3.2 analog input

    Is this just for greater headroom before the damage-threshold voltage is reached?
  8. J

    Encoder Library Qestion

    Ground shields at one end to avoid ground loops. Are your two systems intentionally isolated including the grounds? If designed that way then I suppose that may work but otherwise they would commonly share a ground. No pun intended.
  9. J

    Encoder Library Qestion

    Wrap each motor lead through a ferrite a few times. Put a power filter on the input to the motor power supply. Shield your signal cables and ground the shield at one end.
  10. J

    Nerding out with the Irrigation System

    Why differential input mode?
  11. J

    DC servos and ferrite rings: on the motor, on the encoder, or both?

    When I built a large machine tool using brushless motors (grad school) we used ferries on the motor leads to reduce radiated noise. They were quite effective. I imagine, though, that ferrites on the signal wires may also help by suppressing the induced noise. One would think that they should be...
  12. J

    pwm synchronize with external event

    Since you want zero-cross detection, couldn't you use a comparator circuit for that and then have that provide the sync signal for PWM? Or something like this: Or this, which is closer to what I was imagining...
  13. J

    2Hz analogWriteFrequency on Teensy 3.1

    Why not just use theremingenieur's code, which will accommodate the frequency range.
  14. J

    2Hz analogWriteFrequency on Teensy 3.1

    I can confirm that this works as desired, thank you so much. Am I correct that, based on section 36.3.3 of the Reference Manual (pp. 780-81), each FTM may select a different clock and/or prescale? But each channel within a given FTM shares that clock and prescale selection (based on 36.3.6)...
  15. J

    2Hz analogWriteFrequency on Teensy 3.1

    This is fantastic, thank you. I need to spend some time with the reference manual to understand your code and what else may be impacted by changing the clock source for the FTM. No doubt it may mean that I should have chosen certain pins for the outputs of interest. (My board uses pins 23 and 32...
  16. J

    2Hz analogWriteFrequency on Teensy 3.1

    I'm curious about lower limits for PWM output too. Is there a practical limit where it makes more sense to switch to using a software-based implementation of PWM? For my application, I will be modulating a solenoid water valve, so the fastest PWM cycle I will want is ~1 Hz. I'm interested both...
  17. J

    Teensy 3.1 and ESP266 UART communication issue

    It does seem suspicious that the buffer is 64 bytes. Why not try increasing it and see what happens?
  18. J

    switchable 12V pull-up resistor

    Thank you that helps my understanding considerably. Is there any reason to use the PNP instead of a p-channel MOSFET?
  19. J

    Teensy to MLX90621ESF Design Review request

    What an awesome sensor. Do you have a data sheet for it?
  20. J

    switchable 12V pull-up resistor

    Thanks. Do I not need a series resistor between the Teensy and the NPN?
  21. J

    switchable 12V pull-up resistor

    Thank you Paul. I really appreciate your help (and great products). I had thought that reducing R3 may be in order, just wanted to stay well clear of the 20V max voltage differential. I will go with your recommendation.
  22. J

    Highly optimized ILI9341 (320x240 TFT color display) library

    Isn't the output enable of the 74AHCT125 an inverse input, so that the outputs are enabled with the OE_ input is LOW?
  23. J

    switchable 12V pull-up resistor

    So maybe someone is willing to comment on this schematic? (Adapted from post 11 of this thread.) It uses an NPN transistor to drive the P-channel MOSFET. Since the car operates at ~14.4V, the resistor dividers would mean the gate is about 7V when the transistor conducts, if the K line were at...
  24. J

    switchable 12V pull-up resistor

    I'm using Teensy 3.1 in an automotive interface that includes a connection to the OBD2 k-line. That specification requires a terminating 510 Ohm pull-up resistor from the k-line to +12V. If there is an external device connected to the bus, it will have a terminating resistor; when there is no...
  25. J

    How to stop loading Teensy loader after compile?

    Why not just compile for Arduino Micro?
  26. J

    digitalWrite doesn't work after analogWrite on the same pin

    This just got me. Is there any reason to redefine the pin to turn the output off? I was using digitalWrite(pin,LOW), which didn't work so I tried analogWrite(pin,0), which did. That seems fine but I just want to make sure there's no reason to do something different.
  27. J

    Sim racing button box

    I always recommend Teensy over Arduino. I have found it to be so much better from a capability perspective and I think Paul's software contributions would be impossible to overstate. They are magnificent.
  28. J

    Teensy Switch?

    Does the switch ground the input?
  29. J

    relays with Teensy 3.1 help needed

    You have it correct. That's why I recommended that relay module. For just getting things connected, it's completely awesome. And it has all the right features like current-limiting resistors and optoisolation. I have a few of their modules. They also make modules with solid-state relays, if that...
  30. J

    relays with Teensy 3.1 help needed

    Your option 1 sounds right to me. I'm pretty sure that's how I did it, although it was a while ago and I may have been using an Arduino board (5V). Is your 5V supply running the Teensy? In that case they are sharing a ground anyway. Just send 5V to relay_JD-VCC, 3.3V to relay_VCC, GND to...
  31. J

    relays with Teensy 3.1 help needed

    Honestly, you might be better off getting started by using something like this, which you can connect directly to the digital output pins.
  32. J

    Transistor recommendation

    Isn't the TIP120 a Darlington pair? Seems like you'd want a MOSFET for high-speed use. But you said you need 1ms and that the TIP120 is 20 us, so aren't you fine?
  33. J

    Attach Interrupt question

    Don't you have to define count as a volatile int?