Cookie JAR clock of passion

A clock built inside a mineral oil filled jar.

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I wanted to recreate one of my oldest projects from several years ago when I built a similar clock. Only this time, I wanted to apply different techniques and to come up with a better design. So here it is: "Cookie JAR clock of passion 2020".

This clock will scroll through a series of romantic messages and will display one message every hour. These messages are:

- You are my sugar cookie
- You are my honeybun
- Sweeter than honey
- To the moon and back
- To my beloved sweetheart
- Dearest of all
- I love you deeply

*** The full project is posted here and all the other websites out there only contain bits and links that redirect the users to this location. ***

A little bit of history

The first jar clock I created was added to hackaday in 2016, almost four years ago. It was actually a design from 2012:

It was not the only jar clock I created (you can check my other projects and see the other designs I came up with over the years), but it is the only one that I immersed in mineral oil. 

New horizons

Since then I learned many more things about Hardware design and I had to challenge myself to create a remake at some point. 

Updated features

The old design was beautiful and it was creating a perfect ambiance effect in my house. I ended up giving it away as a gift to somebody and that person kept it for a long time. As far as I know, the clock is still functioning up to this day. I noticed that it was having some design flaws, though, and even since then I've been thinking of fixing these in a new iteration. 

   This new clock will be having the following features:

- it will use a RTC to store time precisely and keep it during power loss. The previous version was having an internal lead-acid battery for this, but that is not as light and reliable on the long term. 

- It will show certain love, passionate, scrolling text messages at certain times. Although this device only has simple 7 segments digits, I found a way of displaying coherent scrolling text on it. 

- It will control the light intensity of the display in PWM and this will allow for very beautiful fade and dimming effects during transitions. 

- Completely sealed. The previous version of the clock was having power input wires that were inserted into the jar through a drilled hole into the glass. This was nice for a while, but it started to leak at some point. 

- Clear oil. The previous version used red transmission fluid, but I want to replace that with clear, non-coloured baby oil for better visibility. After all, I aim to create a very detailed masterpiece with this PCB and this needs to be visible. 

- Better microcontroller unit. For the 2016 version I used a PIC16F628. It was a dip package and the entire PCB was huge for a simple clock. I actually used two parallel motherboards. For this design I am switching to MSP430G2553 TSSOP-28.

- Better PCB design. For this year's design I plan on designing a dual layer PCB and have that manufactured at This will give it a better look and it will be able to embed many more functions in a very compact form. 

- Better user interface. The last prototype was having all the buttons immersed into the fluid and that was making it very hard to set without sticking your fingers into the oil. This new concept will be having an elevated side of the PCB that will stick out of the liquid. 

- Much more stability in everything. The RTC will be having a backup coin battery so no information will be lost during transient voltages. In addition to this the input power supply will be a very smooth filtered linear one. 

Cookie JAR clock of passion 2020_A3_(Goodbye 2020)_backup.txt

special Firmware for the Goodbye 2020 contest

plain - 20.75 kB - 11/17/2020 at 00:01



junction box to be glued on the back side of the jar

Standard Tesselated Geometry - 60.43 kB - 11/13/2020 at 00:36



junction box to be glued on the back side of the jar

Standard Tesselated Geometry - 24.30 kB - 11/13/2020 at 00:36


3D printed supports.stl

spring supports to be clipped into the mounting holes of the PCB. They hold the PCB in place inside the jar.

Standard Tesselated Geometry - 12.78 kB - 11/13/2020 at 00:34


plain - 20.75 kB - 11/12/2020 at 01:04


View all 8 files

  • 1 × 800ml glass jar with gasket or sealed lid
  • 1 × 5 to 15V power brick General DC permanent power source 1.5A min
  • 1 × 1l transparent silicone baby oil almost any type would work
  • 1 × PCB Electronic Components / Misc. Electronic Components
  • 1 × LM317 (TO263 - other packages work too) Power Management ICs / Linear Voltage Regulators and LDOs

View all 28 components

  • Special Goodbye 2020 contest firmware

    Marius Taciuc11/17/2020 at 00:48 0 comments

    I added a special firmware that will display the message "Goodbye 2020" among the other messages that were mentioned above. 

       I hate to break it to you, but for me, personally, 2020 was not such a bad year. So this is the reason for why this message fits well among the other messages in my clock. Since I'm living in a 3rd world country, 2020 didn't bring any major negative change. This country I'm living in at the moment didn't experience any economic crisis yet and we hardly had any viral spread. Everything stood the same around here.

       It has been a good year for me. I experienced many personal achievements, I won international contests, my youtube channel got monetized, my kids learned to ride the bike and we took a cat. I was able to spend dozens of hours building and flying model planes with my son and I feel we had some priceless quality time together. Me and my wife turned 10 years of marriage and we both feel like we recently took our relationship to a higher level of trust, friendship and intimacy. We feel like our career paths are going in the right direction and we experience a feeling of complete satisfaction as we continue to serve with these aid organizations we involve with. We managed to invest so much into educational projects for the children of the 3rd world communities and we feel blessed in everything because we focused on giving and not on receiving. 

       Before everybody in the western world dislikes my post and starts trolling me, I want everybody to know that I am only posting this comment in order to encourage you all. There is life after the pandemic. Have faith and let us all hope for a better 2021. There is a full half of the glass there somewhere and we can all find it. Be kind to one another, show love and compassion and have faith in God.

    Greetings from PNG. 

  • Why I didn't drill the glass for the wire?

    Marius Taciuc11/14/2020 at 02:31 0 comments

    I did drill a hole into the glass for my last similar project. I sealed it up with transparent silicone and I was very happy that it didn't leak. At least this is what I thought at the moment. Several months later I noticed that the power brick that I had under the desk was all greasy and it was having an oily aspect. When I was putting my hand on it I could feel my fingers oily afterwards. I realized that the oil was very slowly leaking through the core of the threaded wire from the jar into the power brick below. 

  • Springs PCB supports

    Marius Taciuc11/13/2020 at 00:41 0 comments

    I added the files for the springy supports that hold the PCB in place inside the jar. 

    You have to clip them into the mounting holes of the PCB and then insert the PCB inside the jar. The tails of these clips are flexible (I used PLA plastic) and they will act like some springs in order to keep everything in place. 

  • How the fonts look like

    Marius Taciuc11/12/2020 at 01:41 0 comments

    Like I said in the beginning, the clock displays these 7 messages:

    - You are my sugar cookie
    - You are my honeybun
    - Sweeter than honey
    - To the moon and back
    - To my beloved sweetheart
    - Dearest of all
    - I love you deeply

    And they look like this:

    You can also modify these messages in software and make them customized to your desire. Download the firmware and modify the texts at the top side of the code. 

       At this point, the messages come in order and they have no randomization algorithm. Each new hour, the next message in the list will play and it will do this continuously regardless the day of the week or month. 

  • Added firmware

    Marius Taciuc11/12/2020 at 01:22 0 comments

    I added the firmware into the Files section. Use the MSP430 launchpad like seen in the image:

    The green wire is TEST and the yellow one is RST. 

    The programming header is a 4 pin DIP connector with the following order:

    ---- red ----

    -- green---

    -- yellow -

    -- black --

    Connect the black (GND) to the square pad hole on the board. The red wire usually stays disconnected from the launchpad. In this case, the clock needs the external power to be connected to it during programming and debugging. 

View all 5 project logs

  • 1
    Ordering PCBs

    I just added the pcb files. I created them in DipTrace and I ordered them from . For an easier experience, I also added a zip folder with the exact gerbers I used to order this. If you want to replicate this project for yourself, don't hesitate in ordering your pcb copy today. These guys deliver worldwide and they even send to my temporary location in Papua New Guinea. The communication with them was great and so far the PCBs were state of the art. 

  • 2
    Find a lid jar

    For this project I used a 800ml gasket sealed cookie jar, but I guess other similar jars will do the same thing. 

    The dimensions of the PCB are 80x115mm

View all instructions

Enjoy this project?



Marius Taciuc wrote 11/14/2020 at 01:52 point

I dedicate this project to my sweet wife, Mihaela. This year we celebrate 10yrs of marriage. 

  Are you sure? yes | no

Ken Yap wrote 11/14/2020 at 02:17 point


  Are you sure? yes | no

Ken Yap wrote 11/13/2020 at 00:51 point

👍 I liked your original project and I like this one too. I always thought it a good test of confidence in the hardware working; rework would be messy. I suppose one could use the oil for light or heating in a dire emergency when you have no power. 😀

  Are you sure? yes | no

Marius Taciuc wrote 11/14/2020 at 01:50 point

Thank you for your compliments. 

  Are you sure? yes | no

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