Tutorial: Pan-Tilt Head

This tutorial presents the construction of a motorized pan-tilt head as an example of using the design approach of the kit. This device could be used to position a camera, mirror, gel, prop, etc. It uses two stepper motors, assumed to be driven using the grbl firmware for Arduino CNC motion as discussed in Tutorial: Stepper Motor Motion.

This tutorial has no specific deliverables, it is instead a design discussion and an opportunity to build and experiment with a a pan-tilt head. It does not use the kit parts, each element has been individually designed, but it follows a similar approach. The primary design objective has been to minimize cost by reducing component count and fabricating as many parts as possible out of plywood using a laser cutter. This design could certainly be adapted for higher precision using other materials and processes.

Pan-Tilt Parts

CAD sketch of a pan-tilt head. CAD sketch of a pan-tilt head.

This structure uses the following wooden parts cut from 6 mm plywood, ordered roughly from top to bottom. This may all be downloaded from the pan-tilt DXF folder.

Quantity DXF file
2 tilt-tray-flange.DXF
1 tilt-tray.DXF
1 set XL-timing-pulleys.DXF
2 drive-pulley-key.DXF
1 pan-tray-flange-no-motor.DXF
1 pan-tray-flange-with-stepper.DXF
1 pan-brace.DXF
1 pan-tray.DXF
1 pan-axis-spacer-6mm.DXF
2 pan-axis-spacer-30mm.DXF
1 pan-base.DXF

One additional part is cut from either felt or a slippery plastic:

The device uses the following components and hardware:

Quantity Component
2 NEMA-17 Stepper Motor, e.g. KL17H248-15-4A
2 XL timing belt, 60 tooth, 1/4 inch wide
8 M3 x 10 Socket Head Cap Screws (for motors)
2 6mm x 20mm Shoulder Screw
1 6mm x 14mm Shoulder Screw
3 M5 nut (for shoulder screws)
3 M5 x 10mm washer
2 M6 x 18mm washer
4 M6 x 20 Socket Head Cap Screws
4 M6 nut
8 #3 x 1/2 inch flat head wood screws (for pulleys)
4 #4 x 1 inch flat head wood screws (for base)

Configuring Grbl Units

The pan-tilt head has the following drive parameters:

motor steps 200/rev
microstepping ratio 16:1
timing belt drive ratio 48:112

If the desired calibration is in degrees: 200*16*(112/48)/360 = 20.741 microsteps/degree.

Assuming that pan and tilt are on the X and Y axes respectively, the following constitute reasonable grbl parameters for testing. Depending on your application, you may be able to increase the acceleration and speed substantially.

$100=20.741 X axis steps/degree
$110=2700 X axis max rate, degree/minute
$120=45 X axis acceleration, degree/sec/sec
$130=90 X max travel, degrees
$101=20.741 Y axis steps/degree
$111=2700 Y axis max rate, degree/minute
$121=45 Y axis acceleration, degree/sec/sec
$131=45 Y max travel, degrees