Assembly Drawings:

The pictures below gives you a clear idea how the project was elaborated to further stages.

  Step 1) The inner arms were reversed so instead of opening the jars, the device close the lids.

Step 2) The gears and motor are installed which helps rotates both the arms.

Step 3) A rubber sheet was applied to curvatures for friction and strength.

Step 4) A PCB chip was created with all the the components wired to each other.

Step 5) A battery compartment was created along with a top rectangular part that was screwed in to the device.

Step 6) The batteries were installed and the chip PCB chip was screwed to the top part of the device. The sides were also screwed to make sure easy replacements of the batteries after they run out.

Step 7) The product was checked for any hindrance with each component after being screwed together and here is how the final design looks like.



The Printed Circuit Board was designed using the software Inkspace and the schematics are shown in the pictures below.



To see the code, click the following link.


  • The Arduino IDE was used to write and upload the code to our ATTINY84. 

Parts List

Qnty Part Desc Supplier Price/Unit

Hamilton Beach Open Ease Automatic Jar Opener

 Amazon  14.50


 Push-Button SPST W/Red LED  RadioShack  2.99


 P/B NO Switch RadioShack



5VDC/1A SPDT Micro Relay RadioShack 4.99


AA Battery  RadioShack .75


9Volt Battery RadioShack 3.00


ATTINY84 Amazon 6.02


Resistors RadioShack .25


Capacitor 110UF RadioShack 1.05


5V Regulator RadioShack 5.52


OPAMP Amazon .35


AA Battery Holder RadioShack 2.49


9 Volt Battery Holder and battery clip RadioShack 4.48


⅛ Acrylic Sheet HomeDepot 20.00

 Total Approximate Cost to replicate project: $75.35