March is Ladies’s Historical past Month, and we wish to spotlight some superb girls who’ve made influential contributions to science and know-how you in all probability do not find out about! Immediately we’re speaking about Hedy Lamarr, who was born in Austria in 1914. She was a Hollywood actress identified for her gorgeous magnificence and fascinating performances on display screen. Nonetheless, many individuals are unaware of her contributions to the world of know-how and her groundbreaking innovations.
Hedy Lamar and her patent sketch. Supply: Wyld Networks
Her father was a profitable banker and her mom was a pianist. Hedy was raised in a Jewish household and had an early curiosity in appearing and the humanities. As a baby, Hedy was thought of a prodigy, displaying a pure aptitude for each arithmetic and music. She started appearing at school performs and made her skilled appearing debut on the age of 16 in a German movie.
In 1937, Hedy fled a wedding to an older man in Europe and moved to Hollywood and commenced her profession in American movies, altering her title to Hedy Lamarr. She rapidly turned identified for her gorgeous magnificence and appeared in a number of profitable movies within the Forties. Whereas Lamarr is finest identified for her appearing profession, she all the time had a eager curiosity in science and know-how and co-invented a radio steering system known as “frequency hopping” throughout World Conflict II.
All through her movie profession, Hedy stored pursuing her ardour of inventing
Collectively together with her collaborator George Antheil, an avant garde composer she was associates with, Lamarr got here up with the concept of frequency hopping whereas talking about their concern for the security of Allied ships through the struggle.
On the time, radio-controlled torpedoes had been rumored to be in improvement by the Allies. Lamarr was conscious that these torpedoes may simply be jammed by the enemy, rendering them ineffective. Radio jamming is the intentional transmission of radio indicators on the identical frequency as one other communication channel, with the purpose of disrupting or interfering with that communication. She believed that if the frequency used to manage the torpedo was always altering, it will be rather more tough for the enemy to jam the sign and stop the torpedo from reaching its goal.
Lamarr and Antheil, an unlikely pair who modified the world collectively
Antheil and Lamarr had been in a position to strategy this downside in an progressive approach because of their distinctive views, and his expertise as a composer got here in helpful right here. He was very eager about equipment, significantly in pianos, which gave them an concept of the way to maintain the 2 antennas in sync because the frequencies for the communications had been altering. The ship and the torpedo would every have an similar participant piano roll. As an alternative of controlling a musical instrument, the information on the rolls would set every antenna to a sure frequency. By studying the rolls on the similar velocity, the ship and torpedo may maintain leaping frequencies and nonetheless have their antennas synced.
Instance of how FHSS can allow communications to keep away from interference. Supply: ecomputernotes.com
In absolutely developed frequency hopping, the transmitter and receiver quickly change between completely different channels in a predetermined sequence. This sequence is understood to each the transmitter and the receiver, and it’s often designed to cowl a large frequency vary to extend the probability of discovering a transparent channel. Lamarr and Antheil obtained a patent for this know-how and donated it to the US Navy, by no means getting any cash from it.
Lamarr and Antheil’s Patent for the “Secret Communication System”, aka the Frequency Hopping Unfold Spectrum
The know-how was not applied by the army till the Sixties, however it has since grow to be the premise for contemporary applied sciences reminiscent of Bluetooth and Wi-Fi. Regardless of the importance of her invention, Lamarr didn’t obtain recognition for her work till later in life. She was inducted into the Nationwide Inventors Corridor of Fame in 2014, almost a decade after her demise in 2000. Lamarr’s invention has had a profound affect on trendy communications know-how, and her legacy as each an actress and inventor continues to encourage many individuals in the present day. In 2017, a biographical documentary known as Bombshell got here out about her life and accomplishments. Test it out to be taught extra about her!
Here is how frequency hopping works in in the present day’s wi-fi communication techniques:
WiFi: WiFi makes use of a way known as frequency-hopping unfold spectrum (FHSS), the place the sign is transmitted on completely different frequency channels in a pseudorandom sequence. The sign hops between channels a whole bunch of instances per second, and every hop lasts solely a fraction of a second. This helps to scale back interference from different gadgets which may be utilizing the identical frequency channel and improves the reliability and safety of wi-fi communication via WiFi.
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Bluetooth: Bluetooth additionally makes use of FHSS, however it hops between fewer channels than WiFi (sometimes 79 channels). Bluetooth gadgets use a primary-secondary structure, the place the first gadget controls the hopping sequence and timing. This helps to make sure that all gadgets are synchronized and that they’re hopping on the identical frequency channels. Bluetooth makes use of the two.4 GHz frequency band, which is shared by many different wi-fi applied sciences, together with Wi-Fi, cordless telephones, and child screens. By quickly hopping between completely different frequencies inside this band, Bluetooth can keep away from interference from different gadgets transmitting on the identical frequency.
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Instance of Bluetooth frequency utilization for a number of indicators
GPS: GPS doesn’t use FHSS as its major mode of operation, however quite makes use of a direct sequence unfold spectrum (DSSS) method for sign transmission. Nonetheless, FHSS can be utilized to enhance the reliability of GPS indicators in environments the place there may be important interference or jamming. By quickly altering frequencies, the GPS sign can keep away from interference from a narrowband jamming sign that’s centered on a selected frequency. To implement FHSS in GPS, a way known as Binary Offset Service (BOC) modulation is used, which mixes the advantages of DSSS and FHSS. BOC modulation permits for the transmission of a narrowband sign whereas additionally hopping between frequencies to keep away from interference, leading to improved reliability and accuracy.
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Have you ever used frequency hopping know-how? Thank Hedy Lamarr! We wish to hear about your work and what girls have impressed you thru their innovations. Shoot us a tweet @sparkfun, or tell us on Instagram, Fb or LinkedIn.