Session 4b - 19 March 2016 - BitScope version

Other sessions

  • Session 1 : Powering the board, power use, first (bad) trigging and echoes (06 March 2016)
  • Session 2 : Non-controlled pulsing, inverters, better echoes (11 March 2016)
  • Session 3 : Getting controlled pulsing, but width not controlled (15 March 2016)
  • Session 4 : Width of the pulses is getting controlled =) (19 March 2016)
  • Session 4b : Simple data visualisation with BitScope (19 March 2016)
  • Session 5 : moving the transducer to get the first image (20 March 2016)
  • Session 6 : Getting a clinically usable image (28 March 2016)
  • Session 7 : Getting cleaner images - code improvements (3 April 2016)
  • Session 8 : Comparing acquisition speeds (3 May 2016)

    Today

Goal

Getting images through the BitScope tool.

TL;DR

  • Getting images, but more series of points.

Setup

Hardware

  • Murgen 1.0
  • Hackaday Trinket Pro
  • 5/3.3V alim
  • Bitscope micro (BS05)

Give me files

  • Troubleshooting for the install of bitscope is at bitscope/InstallingBitScope.readme
  • The code lies at bitscope/acquire.py
  • The data is at bitscope/bitscope_data/*.log

Remarks

  • Same setup as Session 4, and same remarks apply.
  • Even though MY_SIZE = 18000, wc -l indicates 12000 items. At 20MHz, that's 600us worth of data, or a full two signals

Discussion and issues

Discussion

  • Getting our first pulses with the BitScope DSO:

  • Getting the first logs using BitScope Python API

Issues

  • BitScope only trigs on "wide" pulses, so we had to add a 10us pulse from the Arduino so to trig on this signal, not on errors from the Arduino pulser. We got Pin11 do this, still playing with PORTB.
  • On the following image, we see on the first line that the first pulse is quite wide because the double echo we see at 60us is characteristic of a wide pulse.

Next steps

  • Trigging from Ch A to get Ch B.
  • Getting more info in the files: Time of pulse Sampling frequency Number of pulse ...

Images

Getting a pulse

Issues with trigging from a short pulse: it only triggs on "wide" pulses

Solving the issue of the trigger

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