Fluidic sensor is used to measure passage of film without mechanical contact with counting device. Same sensor system may be used for different sizes of film. System has two fluidic sensors and operates on principle of electrically recording interruptions in air stream

Maciel, A., Jr.

English

NASA Technical Reports Server

Fluidic Sensor
(Interruptible-Jet)
ply 
Fluidic-To-Electric
Switch
sor 
)le-
Flu,,,-.
	 Film 
Switch
August 1972
	 B72-10501 
NASA TECH BRIEF 
Manned Spacecraft Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Indexing Film with a Fluidic Sensor
Film Output of 
Fluidic-To-Electric
Switch 
Perforated Film 
The problem: 
In order to measure the travel of film, rotating sproc-
kets (for perforated film) and pinch rollers (for non-
perforated film) are mechanically coupled to counting 
devices. This method requires changing the sprocket 
when the film size is changed and places a drag on the 
film, especially when pinch rollers are used. 
The solution: 
A fluidic sensor is used to measure the passage of 
the film without mechanical contact with the counting 
device. The same sensor system may be used for different 
sizes of film.
Non-perforated Film 
How it's done: 
A fluidic sensor electrically records interruptions in 
an air stream (see figure). This system has two fluidic 
sensors: one measures the passage of perforated film and 
the other, the passage of nonperforated film. In one 
sensor the perforated edge of the film moves through 
the jet of air. As the film between perforations interrupts 
the air stream, a signal is generated. Since each frame has 
a certain number of perforations, the frames can be 
counted by setting an accumulating register to the 
number of perforations per frame. 
In order to count the frames of nonperforated film, 
the film is run under a pinch roller, which is not con-
nected directly to the counter as in conventional 
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19720000500 2020-03-17T03:34:24+00:00Z
systems. The roller has a shaft attached to a disc. Portions 
of the edge of the disc are cut out, and as it rotates, 
the edge of the disc passes through the air stream of 
the second sensor. Each time a tooth on the disc 
interrupts the air stream in the sensor, a millimeter of 
film travel is recorded. 
The entire assembly can be mounted on a suitable 
track to allow positioning and detenting of the indicator 
assembly at the proper location for each film size. 
Note: 
Requests for further information may be directed to: 
Technology Utilization Officer 
Manned Spacecraft Center 
Code JM7 
Houston, Texas 77058 
Reference: TSP72-10501
Patent status: 
No patent action is contemplated by NASA. 
Source: Anthony N. Maciel, Jr. of

Link Division of

Singer - General Precision Inc.

under contract to
Manned Spacecraft Center

(MSC-14117) 
B72-10501	 Category 02


Indexing film with a fluidic sensor

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