• PCB redesign for 30 pin oled

    gir01/07/2017 at 15:18 0 comments

    So...I couldn't help myself and completely redid the PCB from scratch. The header should be aligned now (had to modify my footprint with the anchor in the center). For the 30 pin variant of the oled i had to remove one of the unused pins; we'll see if that works out. Something else that needs to be seen to be tested out is the slot for the oled's flat flex. It should be large enough to get one "wing" in at a time, but no promises :s

  • Finally: some progress

    gir01/05/2017 at 14:26 3 comments

    I shelfed the project for some time, but recently I have been working on it again. The 20-pin OLEDs aren't available on AliExpress any more (the last seller who claimed to have them didn't have them).

    So I modified the PCB to take the premade assemblies / modules. (I do plan on modifying the PCB to take 30 pin OLEDs)

    I also finally ordered some prototype boards from OSHPark (really streamlined ordering process, just upload the pcbnew-file)

    On the top of the back side you see those solder pads under the screen header: While many OLED modules have 4 pins, all of them have different pinouts. I plan on soldering jumper wires to set the correct connections.

    On this picture you can see all the components involved (except the .1" header and some resistors, which hvaen't arrived yet)

  • working on the PCB again, new source code

    gir08/20/2016 at 14:53 0 comments

    The one and only [Brian Benchoff] published an article on this project. I took this opportunity to update the GitHub repository, as I have completely neglected that one for way too long (will push later today/tomorrow).

    This week I also did work on the PCB again: rerouted some tracks, repositioned the (previously misaligned) header, and added a footprint for an ESP-12 module. You can clearly tell that that is just bodged in by the way all the traces had to be routed. But I managed to stay on two layers, which reduces the price of PCBs massively.

    (that should say ESP12E, not ESP12F - sorry)

    UPDATE: Code and PCB files are now on a new GitHub repository: https://github.com/girst/hardpass-passwordmanager

    The old one is there: https://github.com/girst/hardpass-sendHID

  • This display...

    gir08/11/2016 at 14:08 0 comments

    Last week I had some time to work on the OLED. All the resistors, capacitors and the breakout board finally arrived (they arrived about 4 weeks earlier, but to a different address) and I originally planned on directly soldering the flat flex onto the breakout board (and later the elongated pads on the PCB.

    What I didn' notice in the Aliexpress seller's images was, that the flex is meant to be inserted into a connector, and has a thickend end. I tried to scrape it flat, but soldering it directly to the board was still impossible: the remaining height difference in combination with the solder resist was still to high. So I ripped an IDE HDD cable apart and tried to bridging this gap with bare copper wire. Which worked, but the .5mm pitch, in combination with a .5mm² wire made this procedure very short-circuit-inducing. So I finally gave up and bought the slimmest FPC connectors i could find. No datasheet though - so again it will be trial and error getting those to fit. I'll probably leave the (extremely) elongated pads there, so I can freely position the connector on the first PCB prototype. (the strain relief pads wont be soldered; maybe I'll glue them)

    (i had to write something down - otherrwise this project would become completely dead. it isn't that I don't want to work on it - but i have most of my stuff 300km away, and when i am there, friends and family also cant be neglected)

  • Big update: pcb (nearly) done

    gir06/27/2016 at 16:12 1 comment

    I have made the PCB files! For now, I have removed the ESP8266, because I want to get this thing up and running. Before I send them off, I want to wait for the passives for the OLED, so I can test things out on my spare screen.

    The routing is probably awful, but this is the first PCB I designed.Also, the pads for the 6mm tact buttons extend to the edge of the board - let's see if they come out working :S

    When I tried the fit of the components I have already on a paper printout, I noticed the header pins were a little off in respect to the Pi.

    Soldering the 5mm pitch of the OLED will be a challenge, but this 20 pin version of the screen is the only one that can be centered on the board (the pads of the header connector are in the way with the 30 pin version).

  • pcb design

    gir05/28/2016 at 13:57 0 comments

    i started working on the pcb. i still haven't decided if i want to do the rf-signaling myself or use an esp-module, but here it is:

    the screen i ordered is an .96" 20-pin ssd1306 from alibaba and should only need those two passives (we'll see about that one)

    the crystal is also not finalized, and i will have to move the esp closer to the antenna.

    i plan on "surface-mounting" regular through-hole headers on the bottom side and trimming them short before soldering them through the raspberry.

  • Advice wanted

    gir05/09/2016 at 11:02 0 comments

    so....I want to use this project to learn about PCB design, as I have never done this before.

    The question now is, should I use an off-the-shelf ESP-XX module or burn myself trying to make my own RF circuits? If so, what antenna should I use (ceramic, pcb)?

    questions over questions that revolve un my head...

    If you know anything about this stuff, please let me know!

  • Advice wanted

    gir05/09/2016 at 11:02 0 comments

    so....I want to use this project to learn about PCB design, as I have never done this before.

    The question now is, should I use an off-the-shelf ESP-XX module or burn myself trying to make my own RF circuits? If so, what antenna should I use (ceramic, pcb)?

    questions over questions that revolve un my head...

    If you know anything about this stuff, please let me know!

  • Still breathing...

    gir04/29/2016 at 11:32 0 comments

    Neither me nor my project is dead. Look what came in the mail TODAY, instead of february.

  • Menu: first steps

    gir02/29/2016 at 20:26 0 comments

    Since I have the OLED working now, I started working on the menu screen. I am using the ArduiPi_OLED library by hallard (https://github.com/hallard/ArduiPi_OLED) and was able to reuse a lot of the code from my old hardware password manager, `kee` mk1, which was/is based on the teensy3.0 and also uses a I²C OLED.

    I tried to mimic the interface and parameter style of `dialog`, a TUI style dialog framework, although I simplified it quite a bit:

    sudo ./oled "first option" "second option" "`echo -ne "contains \x19 special chars"`" ...
    it is rather counter intuitive in its return values, as "0" (normally for OK) is now the error return and anything n>0 means nth item selected. This means it will be easy to parse which item was selected with bash or python (or c - i'm not sure yet)

    currently, I don't have the button matrix hooked up, so i control it via the keyboard ("stty raw" mode and j/k for down/up)

    code comming soon!