A self-pulsing oscillator transmits a pulsed signal. The time between pulses and the frequency are controlled by two networks. Variations in the component values in each of the two networks, due to environmental changes, appear as changes in frequency and time between pulses in the transmitted signal. Such a sensor is used to measure physical magnitudes

Mossino, R. L.

Robinson, G.

English

NASA Technical Reports Server

ONE FORM OF CIRCUIT FOR MEASUREMENT 
OF PRESSURE AND TEMPERATURE 
BASIC CIRCUIT 
C2
ure-Se 
Indu
Variable 
Temperature 
November 1964	 Brief 63-10561 
NASA TECH BRIEF	
-I& 
This NASA Tech Brief is issued by the Technology Utilization Division to acquaint 
industry with the technical content of an innovation derived from the space program. 
Tiny Sensor-Transmitter Can Withstand Extreme Acceleration, Gives

Digital Output 
Variable Pressure 
The problem: The measurement and simultaneous 
transmission of physical magnitudes, e.g., pressure 
and temperature, on a projectile. 
The solution: A compact, dual mode, radio-
frequency transmitter, capable of withstanding severe 
accelerations and shocks. 
How it's done: The transmitter is a self-pulsing 
oscillator that transmits a signal in pulses. The time 
between pulses is controlled by the RC, network, 
and the frequency is controlled by the LC 2 network. 
With proper choice of component values, the basic 
circuit transmits at a frequency of 136 mc. Variations 
in the component values in each of the two networks 
due to environmental (e.g., pressure and temperature) 
changes will appear as changes in frequency and time
between pulses in the transmitted signal. To measure 
pressure, the basic oscillator frequency can be varied 
by a pressure-sensitive inductance in place of L or by a 
pressure-sensitive capacitor in place of C 2. To measure 
temperature, the time between pulses can be varied by 
a thermistor in place of R or by a temperature-sensi-
tive capacitor in place of C 1 . The second illustration 
shows the circuit using a pressure-sensitive inductance 
and thermistor for measurement of pressure and 
temperature. 
The sensor-transmitter has a 60-hour operating life 
on its self-contained batteries and a range of 25 feet 
without an antenna. Its transmitting range can be 
considerably increased with the addition of an antenna. 
The device, including batteries, potted in a cylindrical 
(continued overteal) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern-
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights; or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method, 
or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19630000110 2020-03-11T16:48:29+00:00Z
container measures only 7/16 inch o.d. by 7/8 inch in 
length and weighs 2.5 grams. It has successfully trans-
mitted data from projectiles during flight at hyper-
sonic speeds in the ballistic ranges and continued to 
function normally after impact. 
Notes: 
1. Because of its unique ability to withstand high 
accelerations, this device might find application in 
situations where data transmission is required after 
launch to remote locations and subsequent impact. 
Examples of such inaccessible areas might be 
mountainous regions, mines, and oil wells. 
2. The device may also be useful as a sensor and 
transmitter in meteorological, military, police, and 
rescue work.
Inquiries concerning this invention may be directed 
to:
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California, 94035 
Reference: B63-10561 
Patent status: NASA encourages the immediate 
commercial use of this invention. It is owned by 
NASA, and a patent application has been filed. When 
patented, royalty-free nonexclusive licenses for its 
commercial use will be available. Inquries concerning 
license rights should be made to NASA Headquarters, 
Washington, D.C., 20546. 
Source: Gilbert Robinson and Ralph L. Mossino 
(ARC-22) 
Brief 63-10561	 Category No. 01


Tiny sensor-transmitter can withstand extreme acceleration, gives digital output

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