RoboTargets
FREE GENERATOR  ·  PORT ORCHARD, WA

Your printer is lying
about the size.Ours doesn't.

Large ChArUco calibration boards for FRC vision. Every board is measured with calipers before it ships, and the number we measured is printed on the board.

See sizes and prices
PhotonVision · Limelight · OpenCV · 36″ wide format
800.00 800.00 50.000 square DICT_5X5_1000 · 16 × 16 · 225 interior corners · measured, not assumed

Why this exists

Borderless printing silently enlarges your target.

Printers extend the image past the paper edge so ink reaches the border. On a 24″ sheet that is about a 0.7% enlargement — every square on your board is bigger than the number you typed into PhotonVision, and nothing on screen tells you.

The calibration still converges. The reprojection error still looks fine. Your pose estimate is just quietly wrong, and you will never trace it back to the print dialog.

So we measure every board.

Each one gets checked with calipers across a three-square span before it ships, and the measured square size is printed on the board itself. You type in what we measured, not what we intended.

Boards are printed on a 36″ wide-format plotter with pigment ink, bordered, at 100% — no scaling anywhere in the chain, and the pattern is generated as true vector, never rasterized.

Every board

Pattern
ChArUco
Dictionary
5×5_1000
Square size
Measured
Finish
Matte

Specs are printed on the face of the board, so the numbers you need during calibration are in your hand instead of in an email.

Rolled — ships in a tube
SKUSizePrice
RT-R-0403400 × 300 mm$29
RT-R-0604600 × 450 mm$45
RT-R-0806800 × 600 mm$65
RT-R-0909900 × 900 mm$85

Tape it to something flat. Cheapest way to get a big board.

Mounted — 3 mm aluminium composite
SKUSizePrice
RT-M-0403400 × 300 mm$75
RT-M-0604600 × 450 mm$110
RT-M-0806800 × 600 mm$150

Rigid and flat out of the box. Limelight will not calibrate properly against a board that bows.

Shipping not included, will ship anywhere in North America.

Who makes these

I'm Greg. I build autonomous racing robots, and I got tired of calibration targets — either taping wrinkled letter paper to plywood, or paying to ship a plate across the Atlantic and waiting.

So I bought a wide-format plotter and worked out how to print big boards that hold their dimensions. Then I found out my own first print was 0.7% oversized because of a borderless setting, which is exactly the failure nobody catches. Now every board gets measured before it leaves.

These are made one at a time in Port Orchard, Washington. If you need an odd size, a different dictionary, or an AprilGrid for Kalibr, just ask — it's a parameter, not a tooling change.

— Greg Maxwell · gregmaxwell.com

Order

Email what you need. I'll reply with a total.

Tell me the SKU or just the size, and whether you want it rolled or mounted. Teams can be invoiced for purchase orders.

Need a custom size, a different dictionary, or a full 2026 field AprilTag set? Say so.

[email protected]