Author Options:

Circuitry help needed! Answered

So I'm working on a project to build a binary clock style watch. I have found a fairly simple system to replicate though I plan to downsize the circuit to fit within roughly a 40x40mm area, the height I am not too concerned about right now.

Here is the link to the project I plan to replicate:


Now with the circuit presented I plan to break it into two boards(possibly three). The top board would utilize 2.8x3.2mm LED chips and connect them properly for the ATtiny and shift register. The second board would house the resistors, ATtiny, shift register, and buttons. It would connect to the LED board via vertical wires that would pass through the LED board and hold it directly above. On the bottom of the second board would be the battery holder and wires to directly connect the positive and negative leads to the needed inputs from the backside of the board. This would result in the second and third boards being back to back. (And I do plan on designing and etching my own boards for this project)

So my questions for you are:

I want to add a 16.000 Mhz crystal oscillator to the circuit to increase the accuracy of the internal clock of the ATtiny, so where would I add it in?

How could I reduce the output power from the battery to run the system on minimal power so that my battery can last a year or longer?

And is there such thing as a dual sided pre-sensitized pcb board I could use to make the circuits?


The forums are retiring in 2021 and are now closed for new topics and comments.

1 year ago

Just populate the PCB on TOP with the LEDs and the resistors (0201-Size) and the bottom side with the CPU + Needed components there and powertrain.

You know that you can run the ATTiny at 16MHz internally? https://www.hackster.io/porrey/attiny-16mhz-610d41

How to cconnect the external Clock: See Datasheet. It will be Pins 2 and 3.
See https://forum.arduino.cc/index.php?topic=84551.0 aswell....

Just order your 5 PCBs for 2$ at JLCPCB.com and have professional doublesided PCBs and not DIY messy-PCBs... Just spend those 2 bucks and be happy with 5 professional doublesided, drilled, Plated pcbs :)

You will have to put your ATtiny into Sleep or even Deepsleep as much and as fast as possible. Use interrupts from a external 32k-Clock to count those ticks and count up the second if it reaches the 32k-mark. That way, the CPU will sleep or even deepsleep for like 99.99% of the time.