[image of digits] Encoders
An Introduction to Encoders by Odd Parts
Gray code definition from the National Institute of Standards and Technology
Gray code conversion from Numerical Recipes in C

Sensors - Actuators - Encoders - Steppers - Switches
- Realworld Interfacing - Circuits - Robots
Encoders are basically an array of switches arranged in some systematic pattern.
Like their predecessors in pre-computer days, they may be linear, rotary or arranged around a drum.

Paper Tape Reader

An electromechanical device which reads 1-5/8 inch paper tape punched in two groups of 6 levels, for a total of 12.

The mechanical precursor:
player piano paper roll.

Airflite Electronics Drum Encoder
Model: XV-7

An electromechanical device with 26 tracks, unusual circuitry and coding.

Quantity 1


The mechanical precursor:
music box drum.

Hexadecimal Thumbwheel

An electromechanical array of 8 thumbwheel switches.
Each has 16 hexadecimal positions (0-9 and A-F)
and each provides a 4-bit binary coded output.

Muirhead Microswitch Rotary Encoder

Six electromechanical microswitches are arranged in rotary fashion and interconnected with a complex circuit of 6 diodes to provide 8 codings for a bipolar stepper motor.

Sharp Incremental Disk Encoder
Family of
and Similar Device

9 slotted disks rotating inside 9 photointerruptors. Part of the Raster Technologies control panel show at right (the center column of controls is an inset of the rear view).

Quantity 1

Absolute Rotary Encoder Code Disk
Large Image

A radial array of optical sensors reads the pattern on the disk which determins its rotational angle. The resolution is 256 per revolution. Coding is mised: binary for the low order 4 bits and strange for the high order 4 bits.

The mechanical precursor:
music box disk.

Disc Instruments Rotaswitch
Rotary Shaft Incremental Encoder
Surplus Listing
Disc Instruments, Inc. 102 East ... tel: (800)-752-0900

Optical resolution: , 2000 per rotation. TTL compatible.

Quantity 1

Digilog Librascope Shaft-to-Digital Encoder
Model 758

An electromechanical device with two 26-pin connectors.

Teledyne Gurley Versatec Incremental Encoder
Part Number: C-000-012287

Optical resolution:

Quantity 1

Litton Shaft Incremental Encoder
Model: BIC35-362G1A

Optical resolution:

Quantity 1

DATEX Shaft Position Absolute Linear Encoder

Manufacturer's Website

Optical resolution:

Quantity 1

DATA TECHnology Incremental Encoder

Manufacturer's Website

Optical resolution: 500 per revolution, parallel A, B two-bit output.

Quantity 1

TWK Single Turn Absolute Encoder
CE 58-1024 G A 01

Specifications Sheet for CE 58
Specifications Sheet for CE 58-1024 G A01

12V, Optical resolution: 1024 per revolution, Gray code, parallel 10-bit output.

Quantity 3

BEI - Two Axis Gimbal with Absolute Encoders
Big Photo

Optical resolution:
Really complicated, big and heavy (weighs 200 pounds)...

Quantity 1