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 5 : moving the transducer to get the first image ! (20 March 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