Introduction: Hello World: Build a Simple Circuit With the Othermill
The Othermill is a nifty little desktop mill that can fabricate amazing things out a variety of goods. Printed circuit boards for electronics are something it handles nicely.
Here's a tutorial for a basic board to play with. It's the first public project we released for the Othermill: "Hello World!"
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Step 1: Tools and Materials
- Computer with Otherplan installed
- Soldering iron and solder
- Diagonal cutters
- Calipers to measure your board
- “Third set of hands” (optional)
- Safety glasses
- Printed circuit board blank, single-sided, FR-1
- Resistors, 47-ohm (2)
- LEDs (2) We used 3mm red and green ones.
- Battery, coin cell, 3V, CR2032
- Battery holder, to fit the CR2032
- Double-sided tape
- Scotch-Brite pad
- A basic understanding of how a simple electrical circuit works (Here's a nice explanation.)
- Basic soldering (Here's a splendid tutorial.)
- A basic understanding of what milling is.
- The willingness to pick these skills up while you make this project. It might take a little longer, but if you've never done it before, you'll feel like you just invented fire.
If you're feeling adventurous or already know how to design boards in EAGLE, download EAGLE and alter our file so you an have it say anything you like!
Step 2: Set Up Your Othermill: Getting Started
Download the EAGLE .brd file called "Hello World" attached to this step.
If you haven't yet used your Othermill, have a look at our Getting Started guide. It'll show you how to get the machine set up for milling and how to download and install Otherplan, the Othermill motion-control software.
Turn on your Othermill and home the machine when you're prompted.
Step 3: Set Up Your Material
Launch Otherplan, and click on the Setup Material button in the Setup panel.
Use the calipers to measure the exact height, width, and depth of your FR-1 blank.
Select "Custom Width," and add in the x, y, and z dimensions of your PCB. Click Continue and Done.
Step 4: Set Up Your Tool
In the Tool panel, select Change.
The Othermill will lower the spindle slightly to make the tool easier to reach. On the screen in Otherplan, a box labeled "Select and Insert a Tool" will appear.
- The Othermill comes with a set of two wrenches that are for changing out the tool. One wrench is smaller than the other. The smaller wrench is for the thinner part of the spindle, just above the nut at the bottom of the spindle where the tool comes out. The nut on the end is called the collet nut, and the hardware inside of it is called the collet. The large wrench is for the collet nut.
- If the collet nut and collet are not in the machine already, find them in the accessory box the Othermill came with. Snap the collet nut into the collet with the wide, flat side inside the nut, and thread the nut loosely onto the spindle.
- Pop the front and side windows closest to the spindle off of the machine. Place the large and small wrenches on the spindle, the large one on the bottom on the collet nut, and the small one on the spindle where the two flat spots are.
- In Otherplan, select the 1/32" flat end mill from the "Select and Insert a Tool"window's pull-down menu.
- Slide your 1/32'' end mill into the collet. Hold it in place with your fingers and hand tighten until it's tight enough to stay by itself. Squeeze the wrench handles toward each other to tighten the nut further. It doesn't have to be too tight, just secure.
- In Otherplan, continue through the dialog boxes to locate the tool and get it ready to cut. Remember to read the instructions carefully!
The Othermill has presets for a bunch of different tools. This means that feeds, speeds, and other tooling settings take care of themselves, with no fiddling with charts and manuals (trust us, if you're a machinist, this is a big deal).
Step 5: Set Up Your File
Click on Import Files from the Plans panel.
Select HelloWorld.brd from wherever you've saved it. (If you've forgotten where you saved it, it's attached to this step.)
The board design should appear in Otherplan on top of the rendering of the material.
In the HelloWorld.brd panel, select the 1/32" flat end mill as both the trace and the outline tool.
TIP: You can save time and explore a few features of Otherplan by adjusting the size of your traces.
You're now (nearly) ready to cut your board!
Step 6: Insert the PCB Blank
In the Move By panel, select Unload Material. (You can also choose Machine > Load/Unload Material from the menu bar, or use the keys ⌘L on your keyboard). This will bring the machine bed forward.
Put enough double-sided tape across the back of your PCB blank to cover the whole side in one thin layer of tape. Don't double the tape up — this could affect the material height and damage the material.
Square the board up on the lower left-hand corner of the machine bed and press it down firmly.
Load the material again. This will bring the machine bed back into the correct position for cutting your traces!
Step 7: Cut Your Traces
In the Plans panel, click on Cut Traces.
The Othermill will give you one more chance to make sure everything looks right. Verify that the board is secure to the bed, and double check all your settings. Put on your safety glasses, and snap the Othermill's safety windows into place.
Click on Cut Traces again.
The Othermill will descend dramatically to the surface of the material and, with a pleasant buzz, start cutting your traces.
This mesmerizing process will take about 20 minutes. It's a good idea to collect anything you might need and get comfy before you start because you should never leave your Othermill unattended while it's running.
Step 8: Cut Your Through Holes
After the Othermill has cut the traces, it'll return to the home position. Click on Cut Outline in the Plans panel.
The Othermill will begin drilling the through holes for your board.
If you're using a PCB blank that's larger than your finished board, you can let the Othermill continue cutting out the outline of the board after the holes are drilled.
If you're using an FR-1 blank that is cut to size for your board, you can stop cutting after the holes are drilled. To do that, first click the Pause button at the bottom of the Otherplan window, then click the Stop button. This will stop your machine and return it to home without it cutting an unnecessary outline.
Step 9: Inspect Your Finished Board
Bring the machine bed forward by using whichever Load Material command you prefer (see Step 6).
Gently pry the cut board off the machine bed with a flat, blunt tool of some kind. We like this simple scraper. A cheese knife or a paint scraper also works, but be careful not to damage your board.
Wipe the dust off the board with a cloth, or use a vaccuum cleaner with a small attachment. Use a bit of Scotch-Brite to remove any rough edges. Remove the tape from the back of the board with a paint scraper or similar tool. Have a look at the finished board and make sure it looks correct.
It it does, it's time to light it up!
Step 10: Assemble the Board: LEDs
Find the two sets of holes on the bottom corners of your Hello World board.
One at a time, insert the LEDs into the holes, from the back of the board.
The long wire on each LED should be inserted in the hole closest to the outer edge of the board. Push them in all the way, but don't force them!
On the front of the board, bend the LED wires so that they line up with the traces you're soldering them to. (A trace is a line on a PCB that transfers signals and power.)
Step 11: Assemble the Board: Resistors
Insert the resistors into the holes at the top of the board, from the back — just like the LEDs. Resistors have no polarity, so you can drop them in any which way.
Bend the resistor wires to match the traces before you solder them, the same way you bent the LED wires.
Step 12: Assemble the Board: Battery
Drop the battery holder through the remaining holes on the front of the board so that the opening for the battery points up and to the right.
Step 13: Solder!
Solder all your contact points on the LEDs, the resistors, and the battery. Soldering is easy to learn, but if you're new, practice as much as possible.
Clip all the wires close to prevent short circuits.
Once you have everything glued down with metal, you're ready to light up your board!
Step 14: Light Up Your Board!
Slide the battery into its cozy little holder.
Your LEDs should light up, and your board should salute you with a cheery message.
Now that you have the basics, you can make all kinds of things on your Othermill.
Contact us at firstname.lastname@example.org to tell us about your projects (we'd love to hear about them!), ask us questions, and discuss issues.