This contraption is utterly useless... however, the skills are not
This workshop uses these skills
Laser cutting
3D printing
Soldering
DC voltage testing
Wire "stripping"
Some Electrical Engineering (don't worry about this part)
Our first step is to gather all of our materials together
(duplicates are on purpose)
going left-right:
1x yellow wire ~10in in length
1x yellow wire ~1in in length
2x green wire ~4.5in in length
1x white wire ~3in in length
1x blue wire ~4.5in in length
Wire can be found in the tech shop
Color is IMPORTANT, this workshop uses color for where the wires should go
If there are pre-made kits of this workshop, use those, however the metal arm of the switch needs to be bent slightly inwards (see second photo). This can be done in almost any way imaginable.
If there are pre-made kits of this workshop, use those
DPDT - (Double Pull Double Throw)
If there are pre-made kits of this workshop, use those
We must test the motor to ensure it will rotate in the right direction. One way to do this is to connect it to a power source, like a battery or our DC voltage output supply (guide is linked). The motor should be spinning clockwise if the connections are pointing toward you and the "shaft/axle" is pointing away from you. Then mark the top side with tape or some marking (this will show up as a blue piece of tape in this guide).
However, if red-black wires are on them, hold the motor so that the red wires are on the right, mark the motor, and de-solder the wires.
There is one 3D printed part which is an STL in a shared Google Drive, print this with the larger face on the build plate, with any settings, however these usually work well:
PLA
Layer hight - 0.2
Wall thickness - 0.8
Infill - 5%
No supports
Build plate adhesion type - None
The casing is made out of wood, which we cut out with our laser cutter (guide is linked)
The files can be found here (this is a link to a shared google drive with an Adobe file to the parts). This file is EVERYTHING you need for the wood. The ARM is cut using 1/4in plywood while EVERYTHING ELSE is cut using 1/8in plywood.
A simple way of getting around this is "hiding" the other elements by clicking the "eye" icon next to the element in the layers tab, then cut the remaining elements
This is a circuit diagram that we will follow for this guide, notice how everything is color coded
First: make sure you are certified to take the soldering quiz on our canvas to have access to the soldering irons.
Just like the 2 photos on the left, make sure the limit switch looks exactly like the photo, then solder a green wire to the left-most prong, and the blue wire to the right-most prong.
Now time to solder the leads onto the motor. As shown in these photos, with the blue/marked side facing up, take the ~10in yellow wire and solder it to the right lead, then take the ~3in white wire and solder it to the left lead. Make sure to solder them so that they leave the moter going up and away (like the 3rd photo).
The orientation for the DPDT switch doesn't matter, however once you pick an orientation STICK WITH IT. Once you have your orientation, just like the photo, solder the blue wire from the limit-switch to the top right input of the DPDT, just like the magenta-circled part of the photo.
First let's solder the second green wire to the bottom left of the DPDT switch, in the photo to the left this is the far left magenta circle. Then we move onto the junction. This part is tricky, down below is the four step process for the junction where three wires come together.
Solder the ends of the two green wires together
place heat shrink on the wires (DON'T SHRINK IT YET)
Solder the end of the ~10in yellow wire from the motor to the two green wires
Slide heat shrink up and shrink heat shrink
Next, as the photo shows with the magenta circle, is to solder the white wire coming from the motor to the top left connection point on the DPDT.
Now take the small ~1in yellow wire and solder one end to the top left of the DPDT and one to the bottom right of the DPDT (just like the photo)
Finally, we solder the two leads coming from the battery to the DPDT switch, the black wire goes on the middle-top connection while the red wire goes on the middle-bottom connection
Next we must test to see if the circuit works, and to set the correct orientation
1) Test to see if the motor spins clockwise when the axle is pointing away from you… (Make sure the battery casing is on…)
If this part fails then some connection is incorrect when you were soldering. Fix the connection and return back to this step
2) If the motor spins & clicking the limit switch does not turn off motor... then Flip DPDT switch
3) If clicking limit switch turns off motor, the switch is in the right position (leave it in that position)
Use M2 16mm screws and M2 nuts to screw the limit switch in between the limit switch holders. Make sure the orientation is correct like the photo
Screw the motor onto the motor holder using M1.6 screws
Make sure the arm is oriented right (like the photo) and push hard
Glue the limit switch onto the bottom plate, make sure the metal arm is facing towards the center of the wood bottom plate
Screw the motor onto the Bottom plate using M3 12mm screws and M3 nuts (which goes on the bottom side of the bottom plate). The arm should be oriented so that it clicks the limit switch on its own.
Screw the DPDT switch to the top using the washer and nut it came with, make sure the orientation is just like the photo
Glue one of the sides, and make sure the "loop" is facing towards the back like the photo
Glue the back plate to the back, make sure its the one without the lip, it should be flat on the top
Place the swivel (do not glue this piece) so that it looks like the photo, and glue the other side piece to the bottom and back plate, DO NOT GLUE IT TO THE SWIVEL TOP
Now glue the top plate to the side plates (like the photo)
Place the front panel (don't glue this one either) and you are all done!!
As funny as this sounds, the useless box can be dangerous and could catch fire; here's why:
The limit switch needs to be hit/clicked
If the limit switch is not clicked as the motor retracts into the box, the motor will try to continue to move, and since there is an obstacle in the way, the motor will heat up, which could cause it to melt through the plastic motor holder (this has happened), mess up any wiring, and could possibly start a fire
"How do I prevent this?"
In short, make sure that the limit switch is being clicked, you should hear an audible "click" noise when it is clicked. If not, try bending the limit switch more/less
Feel free to look at the example useless box in the DCI lab