Digital Clock #4: Chips ahoy!

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Blog entry by Wes Grimes posted 09-25-2011 11:24 PM 1922 reads 1 time favorited 3 comments Add to Favorites Watch
« Part 3: Digital Clock LEDs finished and mounted Part 4 of Digital Clock series Part 5: Wiring complete. We have lights! »

Added the microchips (1) 74hc595 and (1) uln2003a per digit with 220ohm resistors on every LED. The 595s will serialize the data so that less pins are needed.

I finished one digit so far. I have a good amount of the wiring done on the others, but I still have to connect the LEDs to the resistors and perf board.

I wrote a test program for the Arduino and connected the first digit to it.

Here is what the one digit looks like as an ‘8’:

And here is a ‘5’ I backed up so that the LEDs would not mess with the light sensor on this camera. (and no, there is not a 50 hour…)

And a poor attempt at a schematic:

-- Wes, Garland, TX

3 comments so far

View lew's profile


12102 posts in 3783 days

#1 posted 09-26-2011 02:20 AM


-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Ampeater's profile


440 posts in 3775 days

#2 posted 09-26-2011 05:12 PM

Very nice. I was an electronics engineer before I retired and I appreciate the effort that it takes to design and make something like this.

-- "A goal without a plan is a wish."

View PurpLev's profile


8536 posts in 3676 days

#3 posted 09-26-2011 05:17 PM

very cool!

-- ㊍ When in doubt - There is no doubt - Go the safer route.

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