Measure many times, and print once. 3D printing can be inexpensive, if you take the time to plan out the design. Going through filament until a print works is going to get expensive, but using a precision digital caliper is a good starting point.

 

DESIGNING

Toolbox

I knew what this was going to be from the start, and designed it with enough space to include the electronic components. The front of the toolbox will have a facade of drawers, along with a banner with my father’s dates on the ends, and his name in the center. The overall design is simple, but I’ll need to ensure the pieces fit into each other for a fitting enclosure. Notches will need 0.5mm clearance from the locking piece; 0.25mm in every surrounding direction. The picture frame will snap into the hole on top of the toolbox, and will have its cables running through the hole to connect to the microcontroller in the toolbox itself.

 

Picture Frame

This part wasn’t difficult, so much as I didn’t want a basic picture frame on top of the toolbox. I was trying to design something with tools in mind, but nothing came to mind, other than Employee of the Month award plaque. This could have worked, but I want a portrait mode display, and most importantly, I want to remember my father, not showcase him as an employee. In the end, I settled on a basic case to enclose the TFT display, and cycle through the pictures.

 

COMPONENTS

Power and Microcontroller

The hardware components have been chosen, and they have their place in the toolbox that I designed. The toolbox dimensions are set, and now the components have to be fitted into place. Ideally, the components are fitted into place, and the cables are going to determine the length for connecting throughout the project. The planning to this part is direction of the hardware, to make wiring easier. It’s only a few parts, but it helps with cable management. There are 3 main components that need to be fitted into the rIt has grooves where I’ll add the banner and drawers, to make it look more like the toolbox it’s meant to resemble.​_ear panel of the toolbox itself:

• Power jack
• DC step down voltage regulator (buck converter)
• Arduino Pro Mini

For simplicity, the power jack can go in the bottom left corner, when seen from behind, then wire the pins to the buck converter, and route the voltage out pins to the microcontroller.

 

TFT Display

The TFT display will be in the picture frame enclosure above the toolbox, and have its power tapped from the voltage out pins of the buck converter. The TFT display enclosure will require eight 20-gauge wires to come into the toolbox (2 for power, 6 for microcontroller communications), which won’t require much effort for the hole in both picture frame and the top of the toolbox.

Depending on the size of the display enclosure, the hole might be tight for the wires, and cause unavoidable pinching. This shouldn’t be an issue, but something to consider during the prototype testing. Additionally, the clips that will hold the front of the enclosure to the rear will be on the side, away from the wires coming out of the TFT display, to ensure there isn’t stress on the print or the wires.

 

RESULTS

The rear panel of the toolbox took 18 hours to print, and has the placement for the power jack (bottom left), DC voltage regulator (bottom center; horizontal), and Arduino Pro Mini microcontroller (top center; vertical). I haven’t removed the supports above the microcontroller box, where the display will mount (in the picture), but it’s a clean, sturdy print.

 

The front panel has space for the tongue coming off the rear panel, but does not have a locking mechanism of any sort. I might use glue to hold it together, but that’s a permanent solution where I cannot access the enclosure anymore. The rear took 18 hours to print, and the front panel took 9.5 hours. I’m not going to print this again to redo the design. I rushed into it a bit, and that’s my fault, but now I know what to consider with every build.

 

There are grooves in the front panel, where I’ll add the banner and drawers, to make it look more like the toolbox it’s meant to resemble. The banner has the birth and death date, along with my dad’s name in the middle, and will go in the top groove of the front panel. The drawers will go into the bottom groove, ascending in size; smallest to biggest height.

 

 

The toolbox is completely printed, but won’t be assembled until I’m certain with the results, and the electronics are functioning as expected. Here is a preview of the front of the toolbox, with all the pieces sitting in their respective groove.

 

The picture frame has a front panel that will cover the wires, and secure the TFT display into the main piece itself. The walls on both sides of the main piece (left) hold the display in place, and the groove in the right wall is for the microSD card to safely fit in place, without hitting anything. The front of the picture frame (right) has openings on the bottom for the wires to go down into the toolbox. It’s not clearly visible, but the base on the rear has a hole for the wires to feed into the toolbox itself.