Re-wiring a staples Easy button to be a USB button, but they updated the PCB

KhavallKhavall British ColumbiaRegistered User regular
Hey guys

So I'm trying to re-wire a Staples "Easy Button" to be a single-keypress USB button. I found a couple of instructables on it, and it seems pretty easy... assuming I can figure out where to attach my wires to the buttons PCB. It seems pretty easy on the instructables, because you just sort of hook up the ground to the resistor on the PCB and then there's an exposed hole for the NO input. Then I'm using a TeensyUSB to translate the hit into the USB. So again, pretty easy.


The problem is that Staples have now updated their PCB twice. I found a video about the older updated one with where to wire, but I cannot find anything for the newer update.

My wiring skills are basic to say the best... I can solder just fine, I can kind of read a diagram, and I get the basics of how it all works, but I can't look at a PCB and actually understand how it's functioning to do stuff like this.


I've attached an image of the board, do we have anyone who can stare at boards and figure out where I'd want to solder my ground and digital wires to get just the button inputs? I've got a backup if they've just made that impossible now, but it's be nice to use this.

Thanks collective intelligence!

(Spoilered for picture)
110ehw1.jpg

Posts

  • ecco the dolphinecco the dolphin Registered User regular
    edited September 2015
    From a quick glance at it, I would say:

    * That silvery bit in the center with the OKY/03 immediately below it on the left? That's where the mechanical switch actually triggers. Presumably, if you look at the bottom of your switch, you'll find something conductive that gets pushed down, and electrically shorts the two tracks (ground and switch). That's why there's that web of electrically exposed tracks.
    * That 2M resistor on the right hand side? That's a pull-up resistor, so that if the switch is not being activated, the bottom track sits at roughly Vcc.
    * That big black blob on the top left? Underneath is presumably an IC, which controls the lights for the btuton.


    If you just want to have the mechanical connection (i.e. you don't care about the backlighting), then:

    9krvg8riweaq.jpg

    1.) This is where I'd solder the signal
    2.) This is where I'd solder ground

    There are four track cuts that I've circled in blue - I have no idea what IC is being protected by the black blob, so I can't tell you how it affects the circuit while it's not powered up. Cut those four tracks to isolate the switch mechanism from that IC.

    If you want to keep the backlighting, then you'll need to reconnect VDD/GND to a battery/your power source, not cut any tracks, but still solder to points 1 and 2.

    Just make sure that the voltage at point 1 does *not* exceed the maximum I/O voltage for your TeensyUSB board.

    ecco the dolphin on
    Penny Arcade Developers at PADev.net.
  • KhavallKhavall British ColumbiaRegistered User regular
    Sweet, thanks. I don't need the lighting or any functions other than just acting as a switch, so that should make things a little easier.

    I'll try that once I get a chance. Thanks again!

  • ecco the dolphinecco the dolphin Registered User regular
    Just be careful when soldering to point 2 - I don't have the mechanical assembly, so I don't know if soldering something to point 2 will interfere with the button.

    If it looks like it'll interfere, then replace point 2 with the original "GND" point, and don't do the cut between "GND" and the original switch.

    Penny Arcade Developers at PADev.net.
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