• initial commit!

    ReidDye • 12/30/2021 at 18:32 • 0 comments

    Here are the ideas that my preliminary research has yielded:

    Main format

    There will be a control box at the bottom of a long strip of LEDs.  This box will have a single toggle switch, an led indicator for that switch, a servo to reset the switch, and an ESP8266, for WIFI connectivity and servo control.  

    The idea is that every day, the ESP will send a single clock pulse to a long line chain of shift registers which control all of the LEDs.  The toggle switch will be the data entered.  This way, the long line of LEDs will slowly build up a log of when you did and didn't complete what you said you were going to do.

    After this clock pulse has been sent, the ESP will use a servo to flick the toggle switch back to its off position, ready for another day.  

    For the long strip of LEDs, I've decided to break it up into 5 boards, each 73 leds long.  They'll have four lines connecting each board: power, ground, clock, and data.

    If I have time, I plan to add a web interface so that you can see your progress, dim the lights, or set up a timer system for when to dim and brighten the lights.  But for baseline completion, the only wifi thing needed is preventing the time of day from drifting.

    Parts

    LEDs: 1206 smd leds.  These LEDs are approximately 1.5mm tall, so I should be able to space them at regular 2mm intervals, giving me a final length of 356*2=730mm=0.73m, plus joint length.  That's pretty good!  less than a meter.

    https://lcsc.com/product-detail/Light-Emitting-Diodes-LED_FC-3215WD-460M-white_C130718.html

    Control: these LED drivers.  They're like shift registers, but they have 16 outputs and can regulate current.  

    https://lcsc.com/product-detail/LED-Drivers_TOSHIBA-TB62747AFNG-C8EL_C2653365.html

    With these parts, each block of 73 LEDs will cost ($0.0262/led)*(73 leds) + ($0.7268/driver)*(5 drivers) = $5.55 plus PCB costs.  

    JLCPCB normally charges about $2 for 5 boards, so that's an extra $0.40, but I have no idea how much assembly will cost.  There's no way I'm soldering that many tiny leds by hand.

    [edit] actually, it says "Coupon! Free SMT Assembly for your PCB order", so assembly is free!  and they'll source the parts for me from lcsc.  woohoo!

    Time to open up eagle!