More #FastBot #plotterbuild -- today: assembling the controller box. Parts:
1x 3d printed FastBot box
1x 3d printed box cover (not shown)
1x Arduino UNO (firmware already on board)
1x CNC shield with drivers (already set up)
4x switches (we wired up earlier)
3x 3x8mm machine bolts
4x 3x20mm machine bolts (not shown)
7x 3mm hex nuts
1x 40x40x10mm 5v cooling fan (not shown)
It's a fun day of making things pretty. Let's go.
First step is to mount the UNO board.
Screw three nuts onto the three 3x8mm bolts, all the way to the head. We're using these nuts as spacers.
Slip the UNO into place in the box so the USB port pokes out and the mounting holes in the box are visible through the holes in the board.
Screw the board down with these three holes, as shown: lower left, lower right, and upper right. The hole at the upper left is too close to the headers to handle a pan head bolt, so don't use it. (It's ok.)
What if ---- the power jack on the UNO board sticks out too far and keeps the mounting holes unexposed?
Remove the jack; we don't use it.
By unsoldering, ideally.
With very gentle cutting pliers otherwise.
(I haven't met an UNO board that doesn't fit yet, but it could happen.)
Now we're mounting switches.
Slip the wires of the power jack / switch through the left-most switch hole. Make sure the "ON" position is uppermost. Snap the switch into place.
If you're using a pigtail power jack like I am, wedge/snap it into the hole and cradle on the back corner of the box.
Note the box tells you to use a 12v5A power supply and that it must be grounded (3 prong plug), and that the tip of the power plug must be positive. 12 volts here is a minimum, 24 volts is good.
Get the CNC shield and attach the power supply lines to the power block, red to positive +, black to negative -. Screw down firmly.
Now set the CNC shield on the UNO itself, making sure the shield pins line up with the UNO header holes.
Route the power lines tidily beside the drivers as shown.
Next is the motor lock switch, the toggle with two wires.
This goes next to the power swich, ON side up. Feed the wires through and snap it into place.
The Dupont ends of the wires go to the upper left of the CNC shield, to the pins marked "EN/GND" Doesn't matter which wire goes where.
The controller only feeds power to the motors when the plotter is moving. Otherwise they freely rotate; you can move them by hand.
Locking the motors holds them in place always; useful for pen changes.
Next is the hold/resume switch, with three wires.
Feed the wires through the last rectangular hole and snap it into place, ON side up.
The bottom wire on the switch goes to the white pin on the lower right of the CNC shield marked RESUME. The top wire goes to the white pin marked HOLD. The middle wire goes to any of the black pins adjacent to the white pins.
When flipped "off" (HOLD) this switch pauses any running job. When flipped "on" (RESUME) the job continues.
Finally the emergency stop switch. Remove the nut on the back of the switch, feed the wires through the hole then put the switch in place, then pass the wires through the nut and screw the nut to the back of the switch. Use pliers to make it nice and tight.
The two wires from the stop switch go to the lower right of the CNC shield to the white pin marked E-STOP and the black pin nearby. Doesn't matter which wire goes where.
Last thing is the cooling fan and box cover.
Pass the 3x20mm machine screws through the fan holes, then drop the fan on top.
You want the fan blades to be protected on the inside of the box, so the bare blades should face the box cover, with the label inside the box.
Screw on the nuts firmly and add a dab of glue to make sure they don't loosen.
The fan power gets plugged into the left side of the CNC shield; there are two pins marked 5V/GND.
The fan plug will fit though it may need a little jostling. Red wire goes to the pin marked 5v.
Now you can plug a powered USB cable into the controller box, and the fan should come on.
When putting the lid on the box, the fan goes over the switches, not the CNC shield.
(I should have designed it to only go on one way; oops, bad systems thinking there.)
You can unplug the USB cable, and then unplug the fan, after proving it works.
Next thing to do (but not today Zerg) is wiring up the motors, which may well be fairly annoying, as it will require the computer, and may also require hacking the motor cables. Let's hope not.
We're done for the day and my brain is fried.
Shae M Puckett 🤖🖼