Component Tester Module for the Breadboard Kit V2 : 4 Steps

This is a Component Tester Module for my Breadboard Kit V2 and works with my other Instructable here, which is a "modular breadboard kit" designed to be used with a Stanley 014725R organizer case (which can hold 2 complete breadboard kits). You can find the rest of the parts that work with this module, and instructions for them at that Instructable (here is the link again).

This Instructable is for the one (blue) module shown in the first pic, for the rest of the breadboard kit, check out my other Instructable.

Part of this was remixed from tonycstech's (at thingiverse.com) "12864 Mega328 Component Tester" case, which I used as the basis for the design of the part of this module which holds the Component Tester. Thanks to him for sharing his design:

https://www.thingiverse.com/thing:3205944

Tonycstech's 12864 Mega328 Component Tester Design (which this module uses) is licensed under the Creative Commons - Attribution license. If you remix the the module here, please include the same attribution to Tonycstech, thanks!

I'd also like to note that I am not an electronics expert, just a hobbyist that is trying to get stuff organized. The steps and diagrams here show how I assembled the module which I use, and there may be a better way so as always please use your own judgement. Please let me know if you see something that can be improved. As for the electronics, after the initial design I decided to add some fuses to protect the inputs for the DC-DC converters which I have included in the diagrams. I did not add any reverse protection or anything like that for any of the components, but please consider that if you see the need for it.

If making this, please understand the limits of the components being used, and make your own judgements on where, if, and how you feel additional protection such as fuses, PTC's or diodes are needed to make your project safe for how it will be used. If you see a problem let me know, thanks!

Step 1: Bill of Materials

Parts:

12864 Mega328 LSR Transistor Resistor Diode Capacitor Mosfet Tester (qty 1)
DC DC converter The ones I used have a 5-23V input and the seller stated they have a 3A max - but under 2A is recommended (cheaper on Ebay) (qty 2)
Rocker Switch (qty 2) - rated for 6A 250V;10A 125V,10A 12V. I used switches similar to these, and I have also checked the switches in this assortment which also work (but are a bit loose). There seem to be many of these toggles however so just make sure they fit the cutout which is 19mm x 12.8mm. The switches I am using have a dimension of 17mm x 12.8mm (measuring the body of the switch and not the larger face dimension, and not including the side clips).
DC 2.1x5mm panel connectors, these can be found cheaper on Ebay (qty 3), but make sure to get the ones with the nuts (I bought some on Ebay that did not include them).
Fuses to protect the DC-DC converter, I used a 2.5A fuse since that is what I have on hand (and my power supply only does 2A anyway). I recommend using a fuse to protect the electronics.

Hardware:

M3x8 (qty 9)
M3x12 (qty 2)
M3x20 (qty 2)
M3x30 (qty 2)
M3 nuts (regular, not locknuts) (qty 2)
M3 4mm x 4.3mm brass inserts (qty 8, get some extras though)
M2.5x5 (qty 3) and M2.5 nuts (these are used for the battery holder and can be substituted out of the 9v battery holder is taped or glued in place)

Step 2: Printing

These STL files can all be printed at 0.2mm layer height and you can use the default 20% infill. I used PLA, but it should work with other plastics as well (such as ABS)>

The parts should be rotated and oriented for minimal supports. I found that the tree supports in Cura worked out well. If you use tree supports, I suggest that you also "enable support brim" and use at minimum a skirt with several lines, that will help with the adhesion of the tree supports to the build plate.

The following parts have areas that need special attention since there are small pockets where supports could be a pain to deal with. They are:

MBBKV2-D10-ESR-RIGHT-TOP -and- MBBKV2-D10-ESR-LEFT-TOP

The above parts were printed with the top flat to the build surface (rotated 180 degrees). The only area of concern is the cable management guide which is circled in the 1st pic, it should be clear of supports.

Below is the print list for the left and right side modules, you only need to print either the left or right side parts, not both. The "sides" in the file names refer to the side of the Stanley case the module was designed to fit (see the 2nd Pic). If using this module with the rest of the components from the Breadboard Kit V2 ( ), the same side components should be used. The other parts for the kit can be found at the linked Instructable.

LEFT Side:
MBBKV2-D10-ESR-LEFT-BASE.stl

MBBKV2-D10-ESR-LEFT-handle.stl

MBBKV2-D10-ESR-LEFT-TOP.stl

MBBKV2-D10-button.stl (qty 4)

RIGHT Side:

MBBKV2-D10-ESR-RIGHT-BASE.stl

MBBKV2-D10-ESR-RIGHT-handle.stl

MBBKV2-D10-ESR-RIGHT-TOP.stl

MBBKV2-D10-button.stl (qty 4)

Step 3: Putting It All Together

The assembly steps below explain how I assembled this, but since I put the pics together I decided that I should add a fuse on the input. I am not an electrical engineer, just a hobbyist so please use your best judgement if you make this. If you see something that can be improved, please let me know, thanks!

To assemble, first install the M3 inserts according to the 1st picture. Make sure to fully seat the inserts, none should sit above the surface of the part, and the inserts for the 16mm screws should go in several mm before they bottom out. It can help to use a longer M3 screw as a tool to install them with some glue or heat (I used Clear Gorilla Glue for this).
Next install the switches and the DC connectors. The nuts for the DC connectors can be used on the Output connector, but the there is not enough room on the input DC connector, so there I used some strong glue (Gorilla Glue Clear) to hold the connector in. Some of the connectors were pre-wired and soldered before installing the DC connectors, which was easier than soldering them in the case.
The wiring was completed next, I posted a pic showing how I connected mine up (2nd pic). I recommend insulating the connectors with heat shrink, electrical tape or liquid electrical tape. The diagram shows where I am going to place a fuse to protect the DC-DC Buck converters from excessive current (I plan to use 2.5A fuses since that is what I have on hand). A thin zip can be used to help wrangle the wires. If you want to add a fuse, PTC or diodes, now is the time. Please insulate all the connections with heat shrink, electrical tape or liquid electrical tape.
Next install the DC-DC converters (2nd pic), but don't forget to install the wires on the screw terminals, and drop the buttons in their holes first. The buttons are slanted and should appear parallel with the surface when installed correctly. Use some M3x8mm screws for these and don't over tighten. Make sure the buttons work freely before moving on.
Install the ESR meter and the battery clip that comes with it, no screws are needed yet, but route the wires so they will not get pinched when the case is closed up. If you do not plan to use screws to hold the battery clip in place, you can add a small piece of double sided tape now or a few drops of glue..
Tuck in and route the wires so they are not going to get pinched when the case is closed up, There is a pinch point at the bottom edge of the DC-DC converters, so the wires need to be clear of that area (since there will be little clearance between that edge of the converters and then base of the case). Before closing it up, it's a good idea to verify all the wiring is correct and maybe test things out. Take note of the maximum input voltage of the DC-DC converters, mine have a maximum 23v input (5-23V range). To be safe I used a 19V DC supply with a positive + tip.
Next the handle can be assembled with the two M3 nuts (not locknuts) installed as shown in the 3rd pic. If you have difficulty getting the nuts installed, make sure all the support material has been removed. The nuts go into their pockets in the handle at an angle.
To close up the case, the longer M3x20mm and M3x30mm screws noted in the 1st pic were used (don't install the 8mm and 16mm screws yet). These long screws will go through the component tester as well, and hold it in place.
If you are going to use the screws to hold the battery clip, those can be install now. There are three M2x4mm screws and nuts needed to hold the battery clip in place. Make sure the heads of the screws do not sit above the base of the holder (so they will not rub on the battery). Instead of screws, the battery clip can be glued in or double sided tape can be used.
Install the 9v battery for the ESR meter and test the components again.
If everything checks out, the module can be added to the breadboard kit in my other Instructable here. The M3x8mm and M3x16mm screws will be used to connect it to the breadboard base.

I've printed many iterations of this to get things right (probably burned a spool of filament between all the prototype parts :D), but I figure that it's better for me to do that and get it right, than to have other people waste theirs. I am happy with the way this module works and hope it works for you, but if you see something that can be improved let me know, thanks!