Arduino based diy f-stop timer

Discussion in 'Darkroom Equipment' started by Elias, Mar 26, 2017.

  1. Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format
    Hi all, for those interested, this is my diy Arduino based f-stop timer

    A video will be available soon to show how it works and how I developed the interface. Comments welcome
     
  2. OP
    OP
    Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format
    a quick descriptive video is available now
     
  3. Neal

    Neal Subscriber

    Messages:
    1,792
    Joined:
    Dec 3, 2004
    Location:
    Chicago, Wes
    Shooter:
    Multi Format
    Nice!
     
  4. OP
    OP
    Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format
    Thank you Neal
     
  5. Trask

    Trask Subscriber

    Messages:
    1,538
    Joined:
    Oct 23, 2005
    Shooter:
    35mm RF
    Congratulations on bringing this project to fruition. Gives us all something to aspire to.
     
  6. RSalles

    RSalles Member

    Messages:
    142
    Joined:
    Aug 29, 2013
    Location:
    RS - Brazil
    Shooter:
    4x5 Format
    Hi,

    Are you planning to distribute pre-assembled PCB's for this project? I would like to use a F-Stop timer in my lab, but have no time for or resources locally available,
    PS: as your website appears to be in French and you are in Swiss, à quelle ville habitez vous maintenant?

    Cheers,

    Renato
     
  7. OP
    OP
    Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format
    Thank you Trask and Renato

    To Renato, no I am not planning to distribute hardware, for the following reasons.

    This is my very first attempt to build any sort of electronic device: I take full responsability for myself but, as a biologist, I know very well how to kill any human with a single electric shock ! Nevertheless, I will provide soon a list of components and low voltage side schematics.

    For the code, this is also my very first attempt to code in Arduino / C language, therefore I am more than conscious that my code is far from clean and needs to be optimized and documented. It is planned for the next weeks and I will share with the community as I am very grateful to all open source contributors.

    Finally, cidadão do mundo, hoje moro com minha familia em Genebra. Estarei na Bahia em breve, bem longe do RS. Estou a disposição para quaisquer esclarecimentos sobre este projeto, por email para detalhes. Obrigado pelo interesse.

    Thank you all
     
  8. RSalles

    RSalles Member

    Messages:
    142
    Joined:
    Aug 29, 2013
    Location:
    RS - Brazil
    Shooter:
    4x5 Format
    Thanks Elias, as soon as the project is finished - alpha release I mean - just drop a line in the forum, as I'll probably try to go for the parts to assemble it.
    PS: Bem vindo ao forum, morei em Biènne - cantão de Berna, não muito longe de onde vc está, por isso perguntei. Saudações soteropolitanas rsrsrs, e um abraço,

    Cheers,

    Renato
     
  9. klownshed

    klownshed Member

    Messages:
    394
    Joined:
    May 3, 2012
    Location:
    Dorset, UK
    Shooter:
    Multi Format
    Looks very cool.
     
  10. Michael Guzzi

    Michael Guzzi Subscriber

    Messages:
    178
    Joined:
    Jan 15, 2016
    Location:
    Caxias do Sul/RS, Brazil
    Shooter:
    35mm
    Damn, don't know how I missed this thread! Welcome to APUG!

    It's a very, very nice first attempt! Looks very nicely assembled.

    Please do post the code, as an amateur C programmer myself I always enjoy looking at how different people tackle different problems.

    Cheers! (Saudações do RS!)

    Michael
     
  11. Luckless

    Luckless Member

    Messages:
    429
    Joined:
    Feb 9, 2016
    Location:
    Canada
    Shooter:
    Multi Format
    One suggestion to keep in mind when documenting/commenting code:
    Code tells you WHAT the code does, comments tell you what it is supposed to do, and ideally why it is supposed to do that.

    c = a + b; very obviously assigns the sum of a and b to c, and a comment stating as such doesn't add much.

    A comment that the line is supposed to assign the normalized value of the sum of a and b to c would have been great at helping notice that c = a + b; is in fact the wrong code and is a critical bug.
     
  12. Hans Mulders

    Hans Mulders Member

    Messages:
    72
    Joined:
    Sep 7, 2004
    Location:
    Netherlands
    Shooter:
    Multi Format
    Groups:
    looks very cool Elias.
    I'm interested in the diagram and source code.
    Are you suppling these?
     
  13. OP
    OP
    Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format
    Thank you all for your positive comments, really appreciated !

    Luckless, I will definitely follow your advice, thank you.

    Hans and Michael, I will post code and diagram later, please allow some time to debug, clean and comment code, and draw a diagram. I still have some minor issues with unwanted flickering and one or two unexpected display behaviors. Nothing too frightening but clearly to be addressed.

    Cheers

    Saudações aos Riograndenses !
     
  14. OP
    OP
    Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format
    Hi All,
    as said before, please find the informations for this open-source f-stop timer.

    Please remember that this timer is intended to be of simple use, give some test strips and programming sequences features, but in no case to be a print database and therefore keeps no data on EEPROM memory.

    Any constructive comments, suggestions, corrections, improvements, modifications are very welcome:

    the Arduino code

    the Schematics

    the PCB

    Thank you

    Elia
     
  15. Marco Buonocore

    Marco Buonocore Member

    Messages:
    419
    Joined:
    Mar 18, 2005
    Location:
    Toronto
    Shooter:
    Medium Format
    Thank you for following up with this, and uploading the schematics. I hope people are able to put them to good use!
     
  16. locutus

    locutus Member

    Messages:
    371
    Joined:
    Jun 9, 2009
    Location:
    Finland
    Shooter:
    Multi Format
    For those that want to have PCB's, dirtypcbs.com is really damn cheap and fast.
     
  17. Leigh B

    Leigh B Member

    Messages:
    2,142
    Joined:
    Jan 17, 2011
    Location:
    Maryland, USA
    Shooter:
    Multi Format
    What's an f-stop timer?

    - Leigh
     
  18. OP
    OP
    Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format
    Thank you Marco.

    Leigh, it is a timer which uses f-stops as time units instead of seconds. F-stops follow the same rationale as your camera, adding one stop doubles the time of exposure under your enlarger, therefore, instead of having to do exponential maths to increase or decrease your exposures, you only have to add or substract stop(s), i.e. very simple addition, just as with your diaphragm. In other words, instead of counting 1,2,4,8,16,32..., you count 0,1,2,3,4,5,.... (2`0 =1,...2`5=32)

    This particular timer works in f-stops, and shows the corresponding time on the lower display which is used for countdown.

    F-stops are particularly practical for test strips as they follow the very same rationale as the zone system. Therefore, you may contract or extend your test strip range simply by setting the base time and the increment between zones, according to contrast. For example, using #00 contrast paper, setting an increment of 1/2 stop, your strip will extend over 5 stops: base + 4. Using #5 paper, with an increment of 1/5, your strip will extend over 3 full stops: base + 2. Great for split grade.

    Hope this helps

    Elia
     
  19. Hans Mulders

    Hans Mulders Member

    Messages:
    72
    Joined:
    Sep 7, 2004
    Location:
    Netherlands
    Shooter:
    Multi Format
    Groups:
    Thanks Elias,
    I will look deeper into it these easter days :smile:
     
  20. DerGali

    DerGali Member

    Messages:
    1
    Joined:
    Aug 22, 2017
    Location:
    LA
    Shooter:
    Large Format Pan
    Dirtypcb is a PCB house from China, i found another China pcb manufacturer https://www.seeedstudio.com/fusion_pcb.html is much cheaper than dirtypcb, 10 boards, up to 10x10 are only $4.9
     
  21. OP
    OP
    Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format
  22. OP
    OP
    Elias

    Elias Member

    Messages:
    13
    Joined:
    Feb 11, 2013
    Location:
    presently in CH
    Shooter:
    Multi Format