• Possible STM8 based meter

    3 days ago 0 comments

    I found a USB meter that might have a STM8 inside along with a 4-pin programming connector.  It also have series resistors for the display.

    I'll let someone else play with it.

  • My smallest PCB so far

    5 days ago 6 comments

    It's Friday just before work day, so I sent it off hoping to beat the weekend.

    You know it is a tiny PCB when the postage alone is easily worth $0.95.  When the board is this tiny, it could easily fit into otherwise wasted space in a batch.

    Oops.  flipped the soic foot print.  Have  to redo more routing.  This is why I procrastinate on ordering PCB. When I don't, I miss something.

    This is how it would look sitting on a SOIC20 footprint.  (Too lazy to make up a soic18).  The pads are a bit narrower on the USB meter, but it should hold.

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    It turns out that I can make a PCB adapter that fits the STM8 to the SO18 (wide) pads. I was going to try to make a flex PCB, but decided to try out the making a Castellated Edges 0.8mm (0.031") PCB instead.

    All the GPIO are broken out + 1 pad for the Reset on 0.05" pitch. The pinout is weird as it is a STM8 adapter for the SOIC-18 pin USB meter microcontroller that I have previously wired by hand. 

    It's going to take may be 3+ week from OSH Park.

  • Long time no hacks

    09/04/2019 at 01:11 0 comments

    New hack: KW203 modded with a STM8S003.

    Sorry no PCB as this was a weekend project.  There are some additional component changes etc.

    Why?  Most generic USB meters do not have sufficient resolution to see low current gadgets. My modded meter has a resolution of 1mA and can easily see the current drawn by the LCD meter (3mA) and my USB serial dongle (10mA).   It is a handy tool to have.

    Github: https://github.com/FPGA-Computer/USB-Voltage-Current-Meter

    Project page:
    https://hw-by-design.blogspot.com/2019/08/usb-meter-modding.html
    https://hw-by-design.blogspot.com/2019/09/usb-meter-modding-part-2.html