Smaller Simone Giertz's Good Habit Tracker

A PCB with one column per month, each has approximately thirty switches in series and one LED at the end. 367 Switches. Pure Madness.

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Thumbing through instagram, I find a post by @davedarkocom showing that all the components for his good habit tracker, inspired by Simone Giertz, had arrived.
Something about the sheer absurdity of putting 30 switches in series to light up an LED and doing it 12 times clicked with me. One thing led to another and about an hour later, I had a complete Fritzing PCB (don't tell Brian Benchoff) uploaded to OshPark.
I think I err... invested... about 8 hours soldering this.

The schematic for this is simple. A power plug leads to a master on/off switch. The output of the master switch feeds the first switch in each month column. Each switch in a column is wired in series to the next. The last switch leads to a 1/8W resistor and an LED. The other leg of all the LEDS are tied together and return down the left side of the board to the power plug.

The switches were selected because that's what I was using for the Sinclair Scientific Calculator project and was familiar with them. The center pin is the common. If the stem is thrown to the left, the center and left pins are bridged. If the stem is thrown to the right, the center and right pins are bridged.

You can feed the switches from the left pin and get the output from the center or feed them from the center and get the output from the left pin. 

The polarity of the power plug is not marked. The supply voltage is not marked. The size of the resistor is not marked. The LED polarity is a suggestion. All of those details are left to the user. If in doubt, solder the master switch and a switch column first and then work out the details. I ended up selecting a 9V plug, 4.7K resistor and a blue led, because those are the things I had on hand.

The next step is to design a laser cut base and alignment jig to grab all the switch stems.

x-zip-compressed - 167.14 kB - 08/19/2018 at 17:05


JPEG Image - 108.14 kB - 03/08/2018 at 21:10


JPEG Image - 125.07 kB - 03/08/2018 at 21:10


fzz - 88.39 kB - 03/09/2018 at 02:20


  • The last half...

    Arduino Enigma03/08/2018 at 22:10 0 comments

    And the  soldering continues. It is the same thing over and over and over again. The half way point is reached.

    Time for another teaser picture, only three months to go. The LED is on the wrong side of the board, just 

    to make a point that it works. 

    For the second part of the year, this was the alignment jig. One edge of the inner piece was sanded down so it would fit tight and grab the switch stems. 

    A little past midnight, the whole thing is completed. Time for a final teaser tweet. In the next few days we will photograph and create the project page.

  • The rest of the switches arrive

    Arduino Enigma03/08/2018 at 22:04 0 comments

    250 more switches arrive in the mail... 

  • The first 4 months

    Arduino Enigma03/08/2018 at 22:03 0 comments

    Working out a system to keep all the switches in a column aligned vertically.

    Experimenting with scrap pieces of laser cut materials, using the straight edges to align the cases and putting two pieces next to each other to align the switch stems

    Soldering the switches, the solder fumes visible in the picture.

    Trying different LED colors. Eventually Blue won.

    And the basic concept works. All of the switches have to be ON for the LED to light up. Time to tweet a little teaser picture...

    The solder joints for the first four months. Nothing is bridged, but some of the joints could use a little less solder. I see a few Hershey's Kisses in there.

  • The first batch of switches arrives

    Arduino Enigma03/08/2018 at 21:51 0 comments

    The first 100 switches arrive, combined with 30 something already on hand. We have enough for the first 4 months of the year.

  • The bare board comes in the mail.

    Arduino Enigma03/08/2018 at 21:24 0 comments

    And this beauty from OshPark shows up...

View all 5 project logs

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leumasyerrp wrote 07/25/2018 at 00:54 point

I made up a handful of these PCB so that I could have my own Good Habit Tracker. I didn't have any scrap plywood to make a jig to align the switches so I designed and 3D printed a jig. Here for anyone else interested:

Thanks for this project, great work!

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Arduino Enigma wrote 08/07/2018 at 04:51 point

great work!

I linked to your work here:

Do you have pictures of the completed item?

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leumasyerrp wrote 08/07/2018 at 22:57 point

I do, it is hanging on my refrigerator for now.

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rafununu wrote 03/09/2018 at 14:46 point

Les bras m'en tombent !

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Arduino Enigma wrote 03/17/2018 at 17:24 point

I am glad you are impressed... ;)

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