mborgerson
Senior Member

I would make sure that you use Serial1 and Serial2 as they have the 8-byte transmit and receive FIFOs and that will reduce the receive interrupt overhead. There's no real need to go through the Open, write, Close...

I'll need to see the code to give you any kind of definitive answer to that. My first GUESS is that doubling or tripling the sample rate caused some buffer overflows and you may need larger buffers. My usual...

The most straightforward way to do this is: uint32_t totalSamples = secondsToSample * SAMPLERATE; // pre-calculate number of samples needed based on duration of sampling volatile void samplesCollected =...

It should be straightforward to log for a fixed amount of time by using an elapsedMillis timer which is reset when starting logging. In the loop you would add code to check the elapsedMillis timer and call...

A few experiments might prove interesting-----if somewhat costly in Teensies and time: 1. Does the timing of the damage change if you change the sampling speed and conversion speed? 2. Does the timing of the...

The voltage source was a signal generator with a 50-ohm output impedance. I think we need to make sure we are thinking of the same things. An accuracy of 0.01V means that the measured voltage is within 0.01V of the...

If the EEClick can output a signal of up to 5V, then your combination of 10-Ohm and 10KOhm resistors won't protect the Teensy. It only reduces the input voltage by one part in one thousand. To get the protection you...

On the basis that 100 lines of code is often worth a thousand lines of discussion, I put together a simple program to test over and under-sampling an ~300KHz sine wave and calculating the Peak-to-Peak voltage. The...

The ADC on the T4.0 can be set up with an aperture time of 100nSec or less. @Samsurp specified an accuracy of 0.01Volts in a 4.5 Volt signal, so a 10-bit resolution should be sufficient. I think you could set up...

Unless you subsample at a frequency that is an exact sub multiple of the input sine wave, you will eventually take a sample at a maximum and minimum point. The key to getting this to work is to know the frequency of...

The nice thing about designing systems with a few really expensive sensors is that the funding agencies don't quibble about the cost of upgrading to an MPU with more memory or better peripheral systems. It's not just...

The one used on the oceanographic sensors was the FP07DA103N when I last worked there in 2018. That is a 10K Ohm at 20 deg C unit. It's not in stock at DigiKey, but the 8K Ohm version is available for $195.84 qty 1....

Let's look at the energy balance. Assume you want 8 gallons of water at 160F. Your cold water tap yields water at 60F. Boiling water is 212F. The boiling water is 52 degrees away from the desired temperature. ...

It just occurred to me that this down-conversion scheme might be a nice way to put together an ultrasonic doppler velocity sensor. I've got a handful of 40KHz ultrasonic sensors in the toolbox and lots of time between...

I played around with LTSpice a bit this morning and designed a 4-pole Butterworth bandpass filter with about 6dB gain from 38 to 42KHz and -40dB rejection at 19KHz and LOTS more at 60Hz. It takes a dual op amp, about 6...

My vague recollections that sub-sampling might do the downshifting seems to be valid. I wrote a simple program to collect ADC data at 38KHz and fed it a 40KHz sine wave from my signal generator. The sampled output...

I'll have to review my understanding of signal processing, but it seems you might solve this problem by under-sampling your input at 38KHz. The output may look like a 2KHz sine wave. You may need a low-pass filter on...

I'm not sure those are the parts I found by stepping through the DigiKey search process, but I'm strongly biased toward them. It was DigiKey that made it possible for me to start a small board production facility early...

The last time I played around with the ARM CMSIS FFT on the Teensy it was with the T3.6. I found that a Real FFT took about 1.02mSec for FFT1024 with a Hanning window. A friend is working over the same calculations...

I just transferred a solar energy evaluation program from the T3.6 that I used last summer to the T3.5. I ran into some compilation issues in MTP.h and MTP.cpp in the tests for processor type: #if...

I dug out my LT1867L board and recorded a data file with all 8 channels connected to a 1.5V alkaline battery and sampled at 4000 samples/second. Data from each of the first four channels passed through an 8-pole IIR...

The LT1867 is a capacitive Successive Approximation ADC. The input acquisition time is a nominal 1.1 microseconds, independent of the sample rate. As noted, it is imperative to have good anti-aliasing filters at...

I've used an LT1867 board from another project to successfully collect data on the T3.6. Here is the part of the code that interacts with the LT1867: /**************************************************************...

Or you could consider using an SD File that is pre-allocated. This avoids the necessity for the file system to scan the FAT to find the next file cluster.

Excellent point. I've gone so far as to add a label to the silkscreen for things like SCK, MOSI, MISO, etc. etc. The vias generally take less than half the PCB area of a normal test point. Some of my smaller vias...

That was my thought too. A closer examination of the timing of the low-current part shows that those periods last about the same interval as the timing info shows for an average update of the ILI9341 (about 41mSec). ...

Been there, done that. I got past the problem at the prototype stage by finding a convenient place to cut the traces and do an "X" set of jumpers to switch the signals. I've also added pull-ups by finding a...

Funny you should ask! A few days ago, I had a setup to measure power consumption of the T4.1 while writing to the SD Card. The setup uses a high-side current sensor on the T4.1 power input and measures the current at...

I took a quick look at the GitHub repository and I will probably try implementing it later today. A few things still bother me: 1. The endpoint definitions are different between the T3 and T4 cores in usb_desc.h:...

In a post on this thread: https://forum.pjrc.com/threads/66265-Fastest-way-to-transfer-data-to-from-Teensy-4-0-4-1-and-Windows-10 I gave examples of python scripts and a Teensy 4.1 sketch that transferred data to...