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  1. J

    TCD1304 with teensy 3.2

    Sorry for the late reply. The code posted in reply #23 assumes that there are inverting buffers on the TCD1304 SH and ICG inputs. To make it work with a direct connection, the HIGH and LOW states must all be swapped. This is essentially that same code, but with those modifications, has been...
  2. J

    Getting started with Teensy 3.2 ADC using PDB

    <deleted>, sorry
  3. J

    print cumulative histogram of measurements of analog pin via Teensy 4.x to serial

    Unfortunately that square root has consequences. To get ten times the precision (i.e. one more digit after the decimal point), you have to average 100 times as many data points.
  4. J

    print cumulative histogram of measurements of analog pin via Teensy 4.x to serial

    Useful rule of thumb: if the distribution is Gaussian, the standard deviation of the average is proportional to 1/sqrt(N) where N is the number of points averaged.
  5. J

    Teensy Snake Game - Music Generator

    I like the Snake Game "score" and would be interested in seeing how you generated the notes. Would you mind posting the Teensy code? Thanks!
  6. J

    shorting pins between teensies

    Analog inputs have extremely high impedance and draw negligible current, so a resistor is not needed. However if there is ever a chance that one of the two processors is not powered up, or not properly initialized, then you do need some sort of protection on inputs. A 10K series resistor...
  7. J

    Fft

    To me, the terms magnitude and amplitude, as applied to Fourier coefficients, mean the same thing. What do they mean to you? mag[i] = sqrt(vReal[i]*vReal[i] + vImag[i]*vImag[i]);
  8. J

    Sending 3-axial accelerometer data wirelessly

    You will most likely need to wire up the connectors yourself. Buy them from distributors like DigiKey, Mouser, etc. The UART serial radio modules I have in mind do not come with connectors, for example the HC-12...
  9. J

    Sending 3-axial accelerometer data wirelessly

    1) You may need a particular connector for the sensor. Check the sensor data sheet. 2) The Teensy 4.1 has 8 hardware serial ports. 3) You will probably need to build your own filter. So far, you have not provided enough information on the filter characteristics to make sensible design...
  10. J

    Sending 3-axial accelerometer data wirelessly

    If you don't have specific requirements, forum members can't offer informed advice. I suggest to start with the ADC built into any of the Teensies and determine whether that is satisfactory. If you sample at a frequency higher than 44 kHz, you don't need the input low pass filter. Then, if...
  11. J

    Sending 3-axial accelerometer data wirelessly

    The sensor has a frequency response extending to over 22 kHz With a sample rate of 20 kHz you will need a "brick wall" 10 kHz low pass filter between the sensor and the ADC. Otherwise the data could be hopelessly aliased. What do you have in mind for that LPF? What bit depth does your...
  12. J

    MLX90640 Thermal Camera and a Teensy 4.0

    Looks good! I recommend to give bicubic interpolation a try (it is correctly coded in the driver for the Adafruit AMG8333 module). It is slow, but image appearance is vastly improved over bilinear interpolation.
  13. J

    TCD1304 with teensy 3.2

    Hi, All: I recovered a TCD1304DG on separate small interface board (standard 74HC04 circuit but with MCP6002 buffer/inverter on the analog output) from a discarded Milwaukee Seawater Refractometer, and used a Teensy 3.2 with @Riem's code linked above to grab the data. The ADC library has...
  14. J

    sample rate jitter with modified adc_pdb example, Teensy 3.2

    In case anyone is interested, after a number of experiments I decided that 12 bits/VERY_HIGH_SPEED/100 kHz was too noisy, with obvious sampling artifacts, and settled on 10 bits/HIGH_SPEED. I'm not sure that the observed jitter is detrimental for this particular application, which is peak...
  15. J

    sample rate jitter with modified adc_pdb example, Teensy 3.2

    I would like to sample a single ADC channel at a constant frequency of about 100 kHz and began with the adc_pdb example. I've simplified the example code as well as I understand it, and it seems to work reasonably well. Monitoring the LED pin using my old 100 MHz analog scope shows that the...
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