ANTHONY NISTOR // LINE FOLLOWER

Stackr Line Follower

A front add-on for Stackr. Five reflective sensors on a custom board read a black line, and the robot steers to stay on it.

WATCH IT FOLLOW VIEW THE PHOTOS
// SYSTEM ARCHITECTURE

How the Add-On Reads the Line

A printed housing bolts to the front of Stackr and holds a custom sensor board just above the floor. Five QRE1113GR reflective sensors look down through windows in the housing. A ribbon cable carries those readings to the controller on the robot, which steers the wheels to keep the black line under the bar.

  • Five Reflective Sensors QRE1113GR sensors sit in a row on the board. Each one reports whether the floor under it is the black line or the white surface.
  • Printed Front Mount Purple brackets and a slotted cover bolt to the nose of Stackr and hold the board at a fixed height.
  • Ribbon Cable A seven-wire cable runs from the board header up to the controller on top of the robot.
LINE_TRACK.LOG ACTIVE
1. SENSE

Five sensors look at the floor under the bar

LINE
↓ Send the readings
2. READ

The ribbon cable carries the signals to Stackr

CABLE
↓ Stay on the oval
3. STEER

The robot turns to keep the line under the bar

TRACK
// LINE RUN

Following the Oval

Stackr with the sensor bar on a black oval drawn on a white surface.

LINE_RUN.MP4 LIVE DEMO

On the Line

The add-on rides at the front while Stackr follows the black oval.

// HARDWARE & SOFTWARE

System Component Breakdown

01

Sensor Board

A custom PCB marked RobotiX One, with five sensor channels and a seven-pin header.

02

QRE1113GR

Five reflective optical sensors, one for each window in the printed housing.

03

Printed Housing

Purple side brackets, a tray with five square windows, and a cover with a cable slot.

04

Stackr

The host robot. The bar bolts to the front and the cable plugs into the controller on top.

// PROJECT MEDIA

Build Photos

The bar on Stackr, the sensor board, the printed parts, and the CAD and KiCAD drawings.

On Stackr
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On Stackr

The purple sensor bar bolted to the front, with the ribbon cable up to the controller.

Side View
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Side View

The bar sits ahead of the wheel so the sensors lead the robot.

Sensor Board
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Sensor Board

The finished board with five reflective sensors and the header along the near edge.

Printed Parts
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Printed Parts

Two brackets, the sensor tray, and the cover before assembly.

Schematic
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Schematic

The KiCAD schematic: five QRE1113GR channels and a seven-pin connector.

CAD Assembly
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CAD Assembly

The FreeCAD model of Stackr with the purple bar on the front.

// SLIDESHOW

All Project Pictures

26 photographs and drawings from this build.

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// TECHNICAL SPECIFICATIONS

System Parameters & Metrics

PARAMETER SPECIFICATION / VALUE
Host Stackr
Sensors Five QRE1113GR reflective sensors
Board Custom PCB marked RobotiX One
Connector Seven-pin header and ribbon cable
Mount Printed purple brackets and sensor housing
Track Black oval line on a white surface
Design FreeCAD assembly and KiCAD schematic