Tag: electronics

  • DIY $10 Slack Notification Light

    DIY $10 Slack Notification Light

    [youtube https://www.youtube.com/watch?v=BT3PeNsmyPA&w=560&h=315]

    While being isolated at home, my company uses Slack more heavily than ever, and that Slack chime is starting to get old. What if there’s a physical light that can notify me instead?

    I have a Smoko ambient light and a few of Digisparks lying around screaming “use me!”. So I started the project using a combination of these two.

    Digispark
    Smoko Ami Shrimp Sushi Ambient Light

    The circuit is really simple, just a NPN and a resistor. I used a NPN with a beta (use hFE on datasheet for a rough estimate of beta) of 40, and with a 1K resistor the NPN gives about 130mA to the LED. If you want to do this project too, change the R1 value to match your desired LED current.

    Schematics

    I have to make some “battery adapters” to provide power to the light:

    “Battery adapter” made with nickel strips
    Circuitry wrapped in heat-shrink

    On the software side, I don’t really want to reinvent the wheel and build a USB protocol from scratch, so I used code from blink(1) and adapted it for the Digispark.

    The rest is relatively easy: use the blink(1) client and set up a slack integration with IFTTT.

    Code:

    https://github.com/gyf304/usblight

  • “Adding” a microUSB port to a HDMI recorder

    So the device is here… But it is not what I wanted…

    Apparently there are two types of this device on eBay that look identical, one with a microUSB port, one without. I, of course, accidentally bought the one without the microUSB port. So what is missing from the non-microUSB version? I suspect that if I can figure out the parts missing from the board and fill these in, I might add the missing USB-to-PC functionality I am looking for. The only way to find out is to open it up.

    Okay, the PCB layout looks OK to me, and there is no major part missing from the board. Wait a second: There is already a microUSB port there on the board, the only thing missing on this product is a cut-out for the port on the casing.

    That’s… That is one of the worst designs I’ve seen in a while. It took some serious courage to make this design decision.

    The only thing left for me to do is to dremel out a hole on the casing.