Some work with my AA813B03480B306D773BFD007800AA5F3D83C176E822C5096CA57632284D8D0E friend ;)



  • Validate board
  • Do PRU code
  • Do "datadump" code
  • Do Node.js
    • Explore WebRTC
  • USB connection


  • Transducer sourcing


  • Assembling a small team (24/11/15 -> onwoards)
  • Pre BOM (30/11/15)
  • Prefeasibility study (4/12/15)
  • Finding PCB/PCBA suppliers (7/12/15)
  • BOM
  • Add to the list ADS803E or LTC2315-12
  • A PCB feasibility (Manu, S, A)
  • A PCB pre-design



  • See below \^\^


Dimensioning the data

  • 128 lines/image may be enough at first - at 16 imgs/s thats 2048 lines/s
    • That's 488us per line
  • (15.77 cm x 2) / (154000 cm/s) = 204.805 us - that's 1024 pts at 5MHz
      * That's 204.805 us per line
      * That's 283.5 us of idle time
  • Final image is therefore 128*1024 px
      *  1024 pts for 15.77cm is 6.49px / mm
      * That's 2.1Msps on average

This LOG

Nov 24th 2015

Nov 27th 2015

Nov 28th

  • Tamagotchi hive in a probe?
  • Thinking about the smile on the silkscreen. EO+OH+PI+Pirate?

Dec 1st

  • Thinking of deadlines
  • PHH/BM discussions

    • Rather be going onto SPI : QuadSPI ?
    • LTC5507ES6 to filter ? A rajouter!
    • Better ADC at LTC2315-12
    • DAC: a simple DAC i2c

echOpen discussion

  • Pro/Cons of a shield compared to FPGA/microcontrolleur

Dec 2nd


Dec 3rd

  • New ADCs in mind
  • Orange Pi Plus 2 : A nasty little thing
  • BBB as always coming mostly from element14
      Some limits - not exploiting all ?
      SPI speed with BBB : (up to 32MHz) - which is
  • 16 bits : is it possible to set all 16 pins on pru0 as inputs? I saw you mentioned something about disabling the microSD functionality on the BB to get access to all 16 pins, but I wasn't exactly sure how. -- heartofasquid
      I thought the PRUs had a 16bit parallel capture mode or are all the pins not available on the BBB? (need to consult the docs) section of the tech ref spruh73c.pdf One thought I had was to use both PRUs to capture alternate bytes/words but that was just a thought, again are all the pins available?
      I'd made a mistake, it looks like all of PRU0's GPI pins may be available, if we are happy to lose the microSD (no big loss - there are other ways to get data in/out of the BBB). So, we can theoretically get high-res captures up to about 15bits, if we need 1 pin for the clock.

Dec 4th

Dec 5th

  • Call/Chat Emmanuel - electronic board - 2 months is what he'd expect
  • Discussion S - review of scope / finetuning signals
    • Necessity at 100V to separate HV to avoid interferences / noise
    • Remark: using PRUs, we can go up to 50MHz (at least) from the ADC
  • Validation of parallel ADC
  • Mapping the Shield knowledge graph
  • Followup MIC

Dec 6th

  • Reflexions on documentation coming from this presentation on OSH
  • 5Msps - Parallel - PRU up to 12 bits - can go further than 5Msps (SOA)
  • Buffer has to come (no, not the buffer app - real world buffer)
  • Thinking as well on architecture
      * Motor + transducer + top in the probe
      * Board + BBB (Node.js still..)
      * Output (if necessary)

Dec 7th

  • Busy business day
  • Usual monday meeting
      * awesome progress on mech part. Seems robust, small, ...
      * need to follow the power usage of POLULU ^^
  • What about a webcam video format?
      * WebRTC - awesome stuff at for nodejs + webrtc

Dec 8th

Dec 9th

Dec 11th

  • Update the Culture repertory in our drive :p
  • Piezo suppliers on their way
  • Mapping the DITSO resources - update
  • Apéro !

Dec 12th

  • GP1A57HRJ00F // photo interrupter
  • Server for again 3 days...

Dec 14th

  • Holocracy progress
  • Comments from S: problems with HV system

Dec 15th

  • First elements from A - first draft (pdf file).

Dec 16th

Dec 19th

  • S has started, on it

Dec 20th

Dec 22nd

Dec 27th

Dec 28th

Dec 29th


Seems like the BBB SPI communication rate are around 0.1s to draw the image over SPI.. may be a tad slaw to only display an image


Dec 30th

  • Did automatic backup for the wiki, for the migration - yeahhh
  • Smartassthoughts
    • The absence of deal-breaking flaws is more important than the presence of any extras. You don’t need anything special to succeed. You just need to do the essentials properly.
    • Power is like being a lady… if you have to tell people you are, you aren’t. -- MT
  • FTS
  • Don't forget spider jerusalem's example - bards, journalists, and a merry cacophonic 2016

Jan 6th

  • Trial on PCBCart
  • Render of the Murgen 1.0 board


Jan 8th

  • Small adjustments from the questions raised by PCBCart

Jan 11th

  • Completed the S project -- CLOSED ;)
  • The A project is ongoing

Jan 12th

  • Luc back in France

Jan 15th

  • Boards:
    • Confirmation that Seeedstudio does not ship out of north america
    • Getting other options and quotes from Advanced Circuits, Macrofab (awesome interface), PCB Pool.
  • Need for a filter to get be sure , there's a low frequency component that remains: to remove- and to center around 0V ?

{width="600"} Let's cut it to 500kHz ?

  • For headers, we have
    • 12 input pins on P8 for PRU1 and 1 input pin for PRU1 on P9, these have been assigned for 12bitADC+Clock and the rest,
    • SPI for DAC,
    • Buffer enable and motor control have been assigned to PRU0.
  • For the controls in prototyping:
    • SW1 controls the gain range for TGC
    • SW2 controls the input range of the ADC,
  • Updating the blog as well, integration of disqus

Jan 16th

  • disqus working
  • creating something on makake.. but seems bugged at the moment
  • list of components on the blog
  • discussions with edgeflex (thanks flylabs!) and macrofab (fun, and willing to test a 4 layer project in beta - only working in 2 layers so far)
  • work with S to integrate a high pass filter (1MHz+) following the echo on Jerome's hand
  • Follow up with Charles
    • working on the RP with a student
    • exploring collaborations

Jan 18/19th

Jan 19th

  • Slight tweak of the budgetting for engineering a probe :) we have this GDoc

Jan 20th

  • What about having a µC ( PIC24FJ128GC010 ?) right after the analog part - could be an additional board/cape stacked below (so with microcontrolleur and alimentation)
    • it would stream data like a wifi camera
    • receives the ping from the motor controleur
  • should we be ordering SMD stuff (flux, fer à souder, soufflerie?) - seems an idea
  • Création des modules !

Jan 21st

  • Changed WP template to something more readable
  • Post on HN .. even went 2nd :)


  • Awesome work from Farad


Jan 22nd

Jan 23th

Jan 24th

  • added datasheets
  • @TODO : think about a USB/BT/... output for the board
  • Output ? What format? USB - but I'd rather have wireless ?
      Wi-Fi Direct promises device-to-device transfer speeds of up to 250Mbps

Jan 25th

Jan 27th

Jan 29th

Feb 13th

  • Lots under way..

  • Required: we need to sit with electronics experts to check how Murgen, Tobo, Goblin, and Mira can merge - for a modular board - ideally as easy as possible to use!

  • IDEA: capelec!
  • Need also to push Goblin's files on the repo. Those are made with Eagle, not Altium, so a bit less options, but still interesting to see how to work with those files =)

Feb 15th

Was about time I got some serious litterature review :)

Some others

  • Integrating hardware and software for the development of microcontroller-based systems
  • IDEA: Design of a USB based multichannel, low cost data acquisition system using PIC microcontroller

Feb 16th

  • Waiting for the board ;)
  • Awesome work : Development of a wide band front end echo sounder receiver circuit by Jatin Sharma ( definitely need to contact him)

Feb 17th

Feb 18th

Feb 19th

Feb 21st

Feb 22nd

  • IDEA : interfacing murgen with a FPGA ? Solution here :
  • IDEA: doing a probe emulator? Signal generation upon a pulse transmitted : a physical emulator for the probe head =)

Feb 23rd

  • seems interesting =)

Feb 24th

Feb 25th

  • Boards reached: issue with the 5V and GND - shortage

Feb 26th

  • Further tests. Shortage still exists.
    • Short is not on the PCB. Appears after solder.
  • Found that the RECOM component was designed to be upside down -- need to resolder it. Luckily it was a via component.
    • This would not be the source of the short anyhow.
    • EF recommends that we burn 10A on the 5V plane to see which component would burn.. hmm i'm quite shy to do this :p
  • Documenting the issue on github.
  • Sending back boards to EF.

Feb 28th

  • Starting the interim report.

Feb 29th

  • Found the source of the short, ADL5511, 5V and GND inverted...
    • TODO : amend the altium files to correct the ADL5511 and the RECOM tracks
  • TODO : sampling freq to be documented

Mar 1st

  • Sending back the boards

Mar 3rd

March 4th

  • Testing the board on the morning

Sunday, Mar 6th

Mar 7th

Mar 8th

  • GSCholar pour HV7360 (to solve the issues) : 10.1109/ULTSYM.2015.0140
  • HV7361 : Sharma
  • TODO
    • Pulser: intégrer un schéma sur le readme de murgen
    • VPE est a 5V sur notre board - 3.3 en typical. Logique à remonter?
    • Add a resistance in parallel of the transducer?
  • Damn!! The alimentation voltage was low... because it takes 6.5V to 12V! Will need to put 9V in through the thermal printer alimentation

Mar 11th

  • Session 2 : Non-controlled pulsing, inverters, better echoes

Marc 14th

  • Starting to get echoes

Mar 15th

  • Session 3 : Getting controlled pulsing, but width not controlled

March 18th

  • Sending his board to prof Charles

19 March 2016

  • Session 4 & 4b
    • Testing the board with the transducer
    • Testing with the BitScope

March 20th

  • Getting the image!
    • Assembling everything
    • Coding in python
    • Thanks bitscope

March 21st

  • Doc
  • Modular design in on with Benoit ! Let's check with Sofian
  • TODO:using SPI on the board
    • plugging a SPI
    • pluging the pulseroff in the buffer part?
  • TODO:logo of murgen in vector

March 22st

    • print and distribute the interim report
    • Organizing elections for the association
      • Define responsibilities of all
      • Review of les status de l'association
      • Review of the reglement intérieur
    • Definir who has access to the twitter account
    • Wiki delivery
    • Documentation
    • BM's gerbers, altiums et al
    • Costing of mira
    • License issue on the wiki
    • Budget update - what do we have?
    • Project forecast - where do we go?
    • Restructuration du wiki
    • Page de veille a mettre sur le wiki
    • Creer une page competition
    • Traiter les "objectifs" de la fondation fabre et les finir
    • Gérer les cotisations, faire un appel à cotisation
    • publier les soutenances de F&V?

March 23rd

March 24th

March 27th

  • Getting good echoes with the TGC maxed!

March 28th

  • Playing with bitscope / issue from the noise / usb plugin got !

March 29th

March 31st

April 1st

April 3rd

  • Cleaning the acquired images

April 4th

  • 4T scan conversion algo OK and working

April 5th

April 7th

April 8th

Nice reading =)

  • Basecamp outlines their goals -- which they say have always been the same -- on their website:
    • Have fun
    • Do exceptional work
    • Build the best product in the business
    • Experiment
    • Pay attention to the details
    • Treat people right
    • Tell the truth
    • Have a positive impact on the world around us
    • Give back
    • Keep learning.
  • "We’re also big believers in business 101. We don’t spend more than we earn, we don’t waste money on things that don’t matter, we don’t give away everything for free and hope we’ll figure it out before we run out of cash. We’re in business to stay in business, and we have 15 profitable years in a row to back it up."

April 9th

Some reads on PRUs:

April 10th

  • Sofian is delayed :/
  • Lines are defined !

April 11th

Choice of a uC: "le boulot des microcontrollers, ce qui me gêne sur l'espruino c'est le manque de sortie wifi - si on veut sortir des données en wireless." Deux choix se profilent

  • WICED : STM32F205RG 120MHz ARM Cortex M3 MCU : 17 timers et 3 × 12-bit, 0.5 μs ADCs with up to 24 channels and up to 6 MSPS in triple interleaved mode, 8- to 14-bit parallel camera interface (48 Mbyte/s max.)
  • Le WifiMCU : EMW3165 : M4: STM32F411CE @100MHz, DSP+FPU, 1×12-bit, 2.4 MSPS A/D converter -- Ce qui me fait peur est un WifiMCU de base en LUA, a voir comment repasser sur du plus bas niveau. L'avantage par contre c'est qu'il est dispo chez hackspark, et coute 18€ au lieu des 35$ du WICED =)

Remarques : Avec le M3 tu perds les instructions DSP et un FPU optionnel (cf Par contre je ne sais pas si c'est correctement exploité, ni si on en a vraiment besoin.

Il y a aussi le Module Particle "Photon" (M3 120 MHz et wifi) ou l'Arietta

  • Apparament module fermé

April 12th

  • WifiMCU ordered

c'est vrai que le WifiMCU est plutôt tentant aussi. Faudrait passer un peu de temps à faire un mini comparatif de ces petites bêtes, voir les benchmarker. On peut se faire une petite compétence autour des STM32F4xxx (et leurs 800 pages de docs) avant de passer au FPGA?

Raspi Oscilloscope



  • I’m using a CA3306 ADC from Intersil. This is a 6-bit 15 MSPS ADC with a parallel read out.
  • Buffer : 74HC4050
  • RPi 1
  • 2 SD Cards
  • Nappe + TBone ?
  • Repo mis à jour


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