Intro: Unlimited Arduino Clones: the Otherduino
Hi, this is Owen from Other Machine Co. and I'm going to show you how to make your own Arduino clones on the Othermill! Arduino is a prototyping platform that has a massive user base and tons of tutorials and code available, which allows anyone with the desire to learn how to build fun electronics projects. And if you have some experience with EAGLE (or want to learn), you can customize the circuit board to your specific needs.
This project will take 4–5 hours, but most of that time will be just kicking back while the machine mills the board. Grab a good book and you're all set!
This tutorial assumes a few things:
Step 1: Determine Your Voltage and Power Needs
There are several optional components that you'll get to in the next step. Without them, you can do the following things as far as power is concerned:
- Power the Otherduino with a USB-to-FTDI cable
- Use 5V sensors, displays, and other peripherals
- Power the Otherduino by soldering wires to the board from an external 4–5V power supply or a battery
In order to do the following things, you'll need to add optional components:
- Connect a DC barrel plug from a wall-wart power supply (requires a barrel jack)
- Use a power supply or battery that's more than 5V (requires a 5V regulator and a 10uF capacitor)
- Interface with 3.3V sensors, displays, and other peripherals (requires a 3.3V regulator and a 10uF capacitor. If you want to use a barrel jack, you'll also need the 5V regulator and its 10uF capacitor)
Think about what you'll need your Otherduino to do. Personally, I usually have 5V power supplies or batteries handy (3 AA batteries works great), so I don't need the optional components. Regardless, you can always solder the optional components on later if your needs change.
Step 2: Tools and Materials
- Computer with Otherplan installed
- Flat end mill, 1/64" and 1/32"
- Flush cutters
- Needlenose pliers
- Soldering iron and solder
- Circuit board, double-sided, 5"x4", copper-clad
- Clock crystal, 16MHz
- Resistor, 10K*
- Capacitor, 0.1uF*
- Capacitors, 22pf (2)*
- LED, amber and green or pick your two favorite colors*
- Resistors, 220 ohm (2)*
- Male header, 6-pin, right angle
- Female headers, 20-pin, straight (2)
- ATmega328 microcontroller with Arduino bootloader
- Chip socket, 28-pin
Optional external power materials:
- DC barrel jack, 2.1mm if you want to connect to a wall-wart style power supply
- Regulator, 5V if you want to regulate the wall jack or other power supply to 5V; some are already 5V
- Regulator, 3.3V if you want the option of 3.3 volts. If you want a barrel jack, the 5V regulator is also required.
- Capacitor, 10uF* for each regulator; you'll need two if you're using both regulators
Optional for soldering vias conveniently:
Step 3: Attach the Alignment Bracket and Your Material
In order for the traces and holes on both sides of the board to line up, we need to use the alignment bracket. It's included with the Othermill, as are 3 mounting screws and an Allen wrench.
First, attach the alignment bracket to the bed using the screws and the Allen wrench.
In Otherplan, set up the bracket:
- Click "Setup Fixturing."
- Click "Locate Bracket."
- Follow the prompts.
Attach your board to the bed with double-sided tape, making sure the bottom left corner aligns with the corner of the bracket.
In Otherplan, set up your material. Choose the standard 5"x4" double-sided FR1. Once you've set up your material, right-click it and select Align To > Bracket.
Step 4: Mill the Board
In this step, you'll import the Otherduino design file. Then you'll mill the top side of the board with 2 tools, flip it over, mill the bottom side with 2 tools, and cut the outline. The process will take 3–4 hours, a good portion of which is keeping the running mill company, so grab a good book.
1. First, set up your file in Otherplan:
- Click "Import Files" and select Otherduino5r.brd.
- Select a 1/32" tool and a 1/64" tool.
- Deselect the "Outlines" button. Make sure only Traces and Holes are selected.
2. Click Cut. If a 1/64" tool isn't already inserted, you'll be prompted to insert one prior to cutting.
3. When the cuts with the 1/64" tool are done, you'll be prompted to insert a 1/32" tool. Do so and continue milling the board.
4. When the Othermil is done milling the top side of the board, prepare for the bottom side:
- Wipe or vacuum off the dust.
- Remove the board from the machining bed.
- Peel off the tape.
- Put tape on the side that was just milled.
- Flip the board left to right, line it up with the right corner of the bracket, and press down to attach it.
5. In Otherplan, cut the bottom side:
- Click the "Bottom" button to flip the board.
- If you don't have a 1/16" flat endmill, select Outlines in addition to Traces and Holes (they should all be selected). If you do have one, don't select Outlines yet.
- Click Cut. You'll be prompted to insert a 1/64" tool again prior to cutting.
6. If you have a 1/16" endmill, do the following once the traces and holes are done:
- Turn on Outlines.
- Turn off Traces and Holes.
- Select a 1/16" endmill.
- Click Cut and change to a 1/16" when prompted.
Once the milling all finished, wipe or vacuum off the dust, then remove your board and the rest of the FR1 from the machining bed. Peel off all the tape. Done at last! Now you just have to solder it.
Step 5: Cut Your Headers
Before you solder your board, you need to cut the female headers to size. You've got two 20-pin female headers, and you need to cut them up into 2 sets of 8 pins and 2 sets of 6 pins. Here's how:
- Use your pliers to pull out the 7th pin and the 14th pin from one of the headers, as well as the 9th and 18th pin from the other one.
- Use your cutters to cut through each header at the point where the pins you pulled out used to be.
- Trim away any extra plastic from around the cuts.
- The result will be two 6-pin headers, two 8-pin headers, and some extras which you can toss or save for later.
Step 6: Solder the Headers and Vias
It's time to solder a ton of stuff. Use the diagram included with this step to make sure everything goes in the right place.
First solder the headers, which will make soldering everything else easier because the board will be held flat above the table.
Now solder the vias:
- They're square, and on the diagram, they're yellow.
- You need to put something conductive through each hole and solder it on both sides of the board.
- If you're using eyelets, just drop 'em in with tweezers and solder both ends. I like to solder all the eyelets on the back of the board, then flip it over and solder the other side. For the second side, make sure you don't press down on the tips of the eyelets with your iron or you'll push them back out. Instead, press on the side.
- If you're using tinned wire, thread it through all the holes, then solder both sides of each one.
- If you're not using eyelets or tinned wire, snip off the extra wire from your components (which is technically tinned wire) and cut it into little pieces. Stick those little pieces in the holes and solder both ends. It can be a little fiddly, but it works.
Step 7: Solder Everything Else
Next, solder everything else:
- Chip socket (making sure the divot in the end is pointed toward the closest edge of the board)
- 16MHz clock crystal
- Both 22pF capacitors
- 10K resistor
- Both LEDs
- Both 220Ω resistors
- 6-pin right-angle male header
- Both 6-pin female headers
- Both 8-pin female headers
- Optional barrel jack (not shown)
- Optional 5V and 3.3V regulators and their 10uF capacitors (not shown)
Check your board against the diagram, which I've included again in this step, and as well as the picture of the finished board.
Lastly, take the header pin labels and trim them to size with scissors. Peel off the adhesive backing and apply them to the header pins. We’ve included 2 sets of labels so you can apply them to both sides of each header.
Step 8: Insert the Chip and Upload a Test Sketch
- Once you've got everything soldered, insert the ATmega328P chip into the socket with the little divot pointing towards the closest edge of the board (just like the divot on the socket).
- Plug your FTDI cable into the 6-pin header, making sure the side of the connector that has metal contacts is facing down. Plug the other end of the USB cable into your computer.
- Open Arduino. In the File menu under Examples, open 01.Basics and load the Blink sketch.
- In the Tools menu under Board, select Arduino Uno.
- In the Tools menu under Serial Port, select /dev/tty.usbserial-##### (a bunch of numbers and letters)
- Click the "Upload" button or go to File > Upload to upload your sketch!
If it uploads successfully and the LED on the board blinks, that's really great! If it doesn't, check all your connections against the diagram, and make sure your solder connections are solid.
Step 9: Go Further
Congratulations, you've made your first Otherduino! Now, if you haven't done it already, you can use EAGLE to edit the board file to your specific needs.
Perhaps you have a lot of USB AC adapters (I've got a few) that you want to use to power the Otherduino. Simply remove the 5V regulator and replace it with a USB jack, making sure the power and ground pins on the jack are connected to the right traces on the board. Maybe you have lithium-ion batteries and you'd like to use a JST connector instead of a barrel jack. Maybe you know you'll never need 3.3V regulated 5V or LEDs, so you just remove all those parts from the board, which reduces the time to mill the board. You can even mill two boards at once!
The options are endless, just like the number of Otherduinos you can make. I hope you enjoy this project, and I would love to see pictures of any Otherduinos that you make in the comments! Suggestions for the next version are also welcome. Contact us at firstname.lastname@example.org. We're always happy to hear from you!