In co-operation with ai03, Cartel presents a no frills, cheap ortholinear keyboard kit for those who’ve wanted to try ortholinear, but couldn’t justify the costs on some other kits out there. Just add switches, keycaps, assemble the kit and you’re good to go! The rest is included in the kit.


It’s a 40% ortholinear keyboard kit. That means 48 keys in a grid. Or 47 keys with a 2 key-wide spacebar supported by a Cherry style 2u PCB mount stabilizer*.


* Not included. Not Costar compatible.


Powered by QMK Firmware, you choose your layout and how many layers of commands every key has. Use it as a light travel keyboard, as your home keyboard, or even a project controller. Powered by an Atmega32u4, it’s right at home as a controller for your latest Arduino project too.

How do you get a CONTRA?

CONTRA’s first group buy has concluded, but there are still opportunities for you to get your hands on one of these kits!

Extras Sale: We ordered more units than we sold – on purpose! The primary goal was to cover potential lost and damaged shipments or component failures. Come April 2018, we’re going to put the remainder of those additional CONTRA kits up for sale for $40 USD
Cases: If you’re looking to get a CONTRA or have one, but would like a more polished case to contain it, we are working on case ideas. No price points yet, but stay tuned for teaser renders and timelines
Round Two: Once some time has passed, we’re going to update the PCB, probably select another color, and produce a second round of this low cost kit.

Whichever way you’d like to get a CONTRA, please fill out the form to the right and we’ll reach out when there is news about the options you select.

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Status Updates

March 15th, 2018

Today the shipping provider selected by picked up the bulk shipment for European proxy orders from us. Once this has arrived at the proxy, shipments to customers should begin to go out to their customers.

Further news regarding the sale of extra units should be coming soon!

March 10th, 2018

On March 8th we shipped out the last Priority Shipping orders for US customers and began shipping the First Class orders. Today, we sent out the last of the First Class orders. All US orders are shipped!

We are currently waiting to ship the European proxy their shipment of Contras. Everything is in place on our end and the European Proxy’s end, it’s just waiting on the shipping company to come collect the shipment.

February 28th, 2018

It’s happening! Today we shipped out international orders placed directly on, and we shipped proxy shipments to our Southeast Asia, Australia, and Canadian partners. We also began the shipping process on US orders, starting with those who selected priority shipping.

January 23rd, 2018

Yesterday we received the finalized PCB prototypes. Today we completed assembly and testing of those units, they passed with flying colors. While we had already begun parts orders some time ago, we had until this point held back the PCB order, so that we could be 100% certain that all aspects of the PCBs were satisfactory, from form to function.

January 20th, 2018

We have firmware available! You can use the configuration tool provided on the firmware tab to start planning your Contra’s layout and download the .hex file for it.

We have also posted up our recommended flashing process, and a guide to help you through the process of building your Contra. We encourage you to have a look at those tabs so that you can be familiar with and ready for the process of turning your kit in to a keyboard.

January 16th, 2018

We have officially completed and closed the group buy. We thank everyone for their support and are overwhelmed and grateful for the popularity of this group buy! Additional news will be forthcoming as we progress towards shipping you your Contra.

While we received far more orders than we expected, at this time we still expect to be on time in shipping all US orders out by the end of the week of March 5th, 2018. Proxies will receive their Contras as part of this shipping rush, and will begin shipping to international customers as soon as they receive their units.


Adblock must be disabled for the builder to work!

Keyboard Firmware Builder by Ruiqi Mao
Keyboard Firmware Builder is not officially related to QMK Firmware.
This is purely a third-party tool using QMK as its firmware base.
Contribute on Github!

QMK Firmware by Jack Humbert

Flashing the Pro Micro

  1. Open QMK Toolbox.
  2. Select your .hex filer under “Local file” and set the Micro-controller to “atmega32u4”.
  3. Select the “Auto-Flash” check box.
  4. Plug your Pro Micro in to your computer, a green LED should light up on the ProMicro.
  5. Use a wire to short “RST” and “GND” together on your ProMicro.
  6. Remove the wire. QMK Toolbox should detect a “Caterina device” and begin the flash process. Two red LEDs should flash a number of times.
  7. The red LEDs should turn off. QMK Toolbox should list “Caterina device disconnected”.
  8. Unplug the ProMicro. Plug it back in. Your computer should detect it as a keyboard.
  9. Short “A1” to “A2” with notepad or a similar application open. Characters should be typed.
  10. If characters appear after shorting “A1” to “A2”, your Pro Micro has been flashed successfully. Let’s build!

Reprogramming the Pro Micro

  1. Open QMK Toolbox.
  2. Select your .hex filer under “Local file” and set the Micro-controller to “atmega32u4”.
  3. Select the “Auto-Flash” check box.
  4. Plug your USB cable in while holding down the reset switch.
  5. Release the reset switch. QMK Toolbox should detect a “Caterina device” and begin the flash process. Two red LEDs should flash a number of times.
  6. Remove the wire. QMK Toolbox should detect a “Caterina device” and begin the flash process. Two red LEDs should flash a number of times.
  7. The red LEDs should turn off. QMK Toolbox should list “Caterina device disconnected”.
  8. Unplug the ProMicro. Plug it back in. Your computer should detect it as a keyboard.
  9. Your keyboard should be reprogrammed with your new layout, enjoy!

Step 1

Cut 48 diodes from the included strip. Bend the diode pins 90 degrees (as shown in illustration).

Step 2

Install diodes to the top of the PCB. Solder diode pins where they stick out of the bottom of the PCB. 48 diodes must be used for all switches to function.

!! Warning: Diodes are direction sensitive. Be sure to install all diodes with the black side aligned to the side with the square solder pad and line through the diode outline (as shown in illustration).

Step 3

Install Pro Micro headers so that shorter pins are in the PCB and black plastic is on the bottom of the PCB. Solder pins where they stick out of the top of the PCB.

Install reset button to the bottom of the PCB. Solder reset button pins where they stick out of the top.

!! Warning: Do not install the Pro Micro itself until Step 7.

Step 4

(Optional) Install a stabilizer for spacebars if used.

!! Warning: Only Cherry-style PCB mount stabilizers can be used.

Step 5

Install 5 screws and spacers in to the PCB, so that the spacers are on the bottom (the same side as the Pro Micro legs).

Step 6

Starting from the outer corners, install all switches by snapping them in to top plate and then pressing the pins through the top of the PCB. Solder metal switch pins on the bottom of the PCB where they stick through.

Step 7a

Install the Pro Micro on to the bottom of the PCB so that the USB port faces down (away from the PCB, as shown in Step 7b illustration).

Step 7b

Solder pins to Pro Micro where they stick through. Take care to prevent or remove any solder bridges (solder connecting one pin to another) that may form.

Step 8

Screw the bottom plate to the spacers you installed earlier.

(Optional) Install the provided self-adhesive rubber bumpons to the bottom plate. We recommend installing 5 bumpons, one in each corner and a fifth near the center.

!! Warning: Ensure reset hole aligns with the reset switch.

All Done!

Install your choice of keycaps on to the switches, plug in the USB cable to the keyboard and your computer, and you’re good to go!

If you decide that you need to adjust the layout you setup when you originally flashed your Pro Micro, you can go back to the “Firmware” tab, make the adjustments you need and export the .hex file with those changes. Then check the “Flash” tab directions “Reprogramming the Pro Micro” for how to flash the Pro Micro now that it is installed in the assembled keyboard.

Firstly, I am not responsible if you destroy your keyboard. You need to have basic soldering skills and be comfortable with following basic electronics instructions. If you wire incorrectly you could damage your pro micro. Having said that, here are the basics.

/u/yanfali (with thanks from Cartel!)

Attaching the RGB Strip

As you can see there are 3 pins on the right side of the PCB when it is upside down near the reset switch. They correspond to the Pro Micro Pins GND, SCLK, F7 and VCC (5v). RGB strips with WS series LEDs can be bought cheaply from Amazon or ebay in reels of 1m for about 12USD.
The pins in the strip are directional, and correspond to 5v, DIN (data in) and GND.

ProMicro RGB Strip Wire Color (in image)
VCC > 5V Red
F7 > DIN Blue
GND > GND Green

Taking Control with CONTRA

Software wise you’ll need to download the contra.json configuration file from the online configurator. You can then upload this into


Navigate to the PINs menu and scroll down to the bottom of the page.

Change the WS2812 strip value from N/A to F7.


Now navigate to the keymap menu and assign the following keys;

  • RGB_TOG (Toggle On/Off) required
  • RGB_MOD (Cycle Modes) required
  • HUI/HUD (Hue)
  • SAI/SAD (Saturation)
  • VAI/VAD (Value/Brightness)

Go to settings and change the number of LEDs to the number you installed.

Compile and download your new hex file. Upload this into your keyboard.

Now you should be able to press your assigned toggle key, though it’ll probably come on by default. Use the mod key to switch between different RGB modes for the strip.

Good luck and happy keebing!


Programming Powered by QMK Firmware
Key Count 48 (47 w/2u Space)
Switch Compatibility Cherry MX, ALPS
Stabilizer Compatibility Cherry 2u PCB Mount
USB Type Micro-USB
Top Plate Compatibility Cherry MX, ALPS
Reversible Back Plate Yes
Overall Size 9.1″ × 3.2″ × 0.6″

In the kit

40% Ortholinear PCB 1
ProMicro 1
1N4148 Diodes 50
6mm Reset Switch 1
PCB Plate & Bottom 1
M2 Standoffs 5
M2 Screws 10
Bumpon Feet 6

Customer Builds

(Mouseover for back detail)

Need a cheap switch too?

While supplies last, we’ll throw in a pack of 50 Orange Brown switches for an extra $5 . This is a light tactile switch, with a very subtle bump measuring around 40gf at its peak. The actuation weight drops back to 35gf, before rising to 55gf at bottom out. The soldering pins feature a removable cover (not a standard SIP or Holtite), if this cover is soldered to a keyboard, it becomes possible to remove the entire switch after soldering. Warning: The fit on these covers is very tight, and replacing the switch is difficult. We do not recommend using these with the intent of treating them like Holtites.

We don’t claim this to be a great switch, but it is a competent tactile switch, fairly comparable to the standard Cherry MX Brown. If you just need a cheap switch to go with this cheap keyboard, we think it will do the trick.

Orange Brown Specifications

Tactile Force 35gf
Actuation Force 40gf
Bottom Out 55gf
Switch Mount Plate Mount
Keycap Mount MX Shaft

Important Information

The bottom of the PCB may include different/additional memes at time of shipment. Plate and Reversible Back are also made from PCB material.

This is a kit. Assembly which requires the use of soldering equipment is necessary. There is no minimum MOQ or expected future MOQs that will reduce the price of this group buy. Additionally, in an attempt to speed up our ordering process and the final delivery of the CONTRA kits to you, we are taking payment at the time of order. As we hit internal milestones before the end of the buy, we will begin ordering parts from suppliers and assembling kits for shipment.

Group buy ends on January 16th, 2018. We are hoping to start and finish shipping all orders placed through the week of March 5th, 2018. Orders placed through proxies will be sent to the proxies first in an attempt to speed up delivery of those orders and reduce shipping costs for proxy buyers.

If any obstacles are encountered that we have reason to believe will delay the shipment plan, all buyers will be notified as soon as possible by email, with an explanation of the cause and the expected duration of the delay.

Group Buy Ends
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