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Casio F-91W

February 12, 2024

The Casio F-91W is a digital watch manufactured by Japanese electronics company Casio. Introduced in June 1989[1] as a successor of the F-87W,[2] it is popular for its low price and long battery life.[3]

Casio F-91W
Casio F-91W-1 watch with a resin case and resin strap
ManufacturerCasio
TypeQuartz
DisplayDigital
IntroducedJune 1989[1]

Specifications edit

Design edit

Designed by Ryusuke Moriai as his first design for Casio,[4] the case of the F-91W measures 37.5 by 34.5 by 8.5 millimetres (1.48 by 1.36 by 0.33 in). The case is primarily made of resin,[5] with a stainless steel caseback and buttons, with the manufacturer's module number, 593, stamped on the caseback. The resin strap is 18 millimetres (0.71 in) at the fitting and 22 mm across the widest part of the lugs. The total weight is 21 grams (0.74 oz).

Features edit

The F-91W is a chronograph, featuring a 1⁄100 second stopwatch with a count up to 59:59.99 (nearly one hour). The stopwatch also has the feature to mark net and split time (lap). Other features include an hourly time beep and a single daily alarm lasting 20 seconds and an annual calendar, with adjustment for leap years not supported as the watch does not record the year. February is always counted as 28 days.[6] The watch uses a faint, green LED backlight located to the left of the display for illumination (in earlier versions it was an amber microlight). According to manufacturer estimates, the watch is reported to be accurate to ±30 seconds per month.[6]

The quartz movement, designated Module 593, is powered by a single CR2016 3-volt lithium button cell.[7]

Water resistance edit

The watch front is marked "Water Resist",[6] but Casio reports different values for different variants of the watch. The black version (F91W-1)[8] is "30 meter / 3 bar" (i.e. 100 feet / 44 psi), the ISO standard meaning of which is: "Suitable for everyday use. Splash/rain resistant. NOT suitable for showering, bathing, swimming, snorkeling, water related work and fishing".

Operation edit

 
Casio F-91W, in regular timekeeping mode and using the 24-hour display option. The watch is currently set to sound the alarm and hourly chime

The watch is controlled by three side-mounted push-buttons.

  • The upper left button, labeled "Light", turns on the light, cancels the alarm, resets the stopwatch or marks the split (lap) time, and is used for selecting settings.
  • The lower left button, labelled "Mode", cycles the modes of the watch: time display, alarm, stopwatch, and time/date adjustment.
  • The right button, labeled "Alarm On-Off/24hr", is the function button: when used, it starts and stops the stopwatch, changes the settings currently being adjusted, or switches between the 12- and 24-hour modes, depending on what mode the watch is currently in. Pressing all three buttons at the same time will fill all the cells on the LCD until any button is pressed again.[9]

The time or date is adjusted by pressing the lower left button three times to bring the watch to time adjustment mode. The top left button is used to cycle through seconds, hours, minutes, month, date, day and normal mode. The right button is used to adjust the flashing value displayed. Unlike any other value, the seconds can only be zeroed. Should this happen before 30 seconds, the watch will zero in at the beginning of the current minute. After 30 seconds it will start the next minute as displayed. When the adjustments are finished, the bottom left button can be pressed once to return the watch to normal mode.

The watch display shows the day of the week, day of the month, hour, minute, seconds and the signs PM in the afternoon – or 24H (24-hour clock) – at all times, the alarm signal status (bar of vertical lines), and the hourly signal status (double beep on the hour, shown as a bell) are present when activated in the alarm mode.

In stopwatch mode, minutes, seconds and hundredths of a second are shown.

Usage in terrorism edit

Further information: Seton Hall reports § Detainees' profile
 
This improvised timer for a time bomb was captured in the early 2000s.

The US government became suspicious of Afghans who wore Casio watches due to their ability to be used as timers for improvised explosive devices, a tactic favored by al-Qaeda.[10][11]

According to secret documents issued to interrogators at Guantanamo Bay, obtained[12] and released by The Guardian, "the Casio F-91W digital watch was declared to be 'the sign of al-Qaeda' and a contributing factor to continued detention of prisoners by the analysts stationed at Guantanamo Bay. Briefing documents used to train staff in assessing the threat level of new detainees advise that possession of the F-91W and the A159W, available online for as little as £4, suggests the wearer has been trained in bomb making by al-Qaeda in Afghanistan."[13] United States military intelligence officials have identified the F-91W as a watch that terrorists use in constructing time bombs.[14][15][16][17]

This association was highlighted in the Denbeaux study, and may have been used in some cases at Guantanamo Bay.[18] An article published in The Washington Post in 1996 reported that Abdul Hakim Murad, Wali Khan Amin Shah, and Ramzi Ahmed Yousef had developed techniques to use commonly available Casio digital watches to detonate time bombs.[19] Casio watches were mentioned almost 150 times in prisoner assessments from Guantanamo.[20]

On 12 July 2006, the magazine Mother Jones provided excerpts from the transcripts of a selection of the Guantanamo detainees.[16] The article informed readers:

More than a dozen detainees were cited for owning cheap digital watches, particularly "the infamous Casio watch of the type used by Al Qaeda members for bomb detonators."

The article quoted Abdullah Kamel Abdullah Kamel Al Kandari:

When they told me that Casios were used by Al Qaeda and the watch was for explosives, I was shocked... If I had known that, I would have thrown it away. I'm not stupid. We have four chaplains [at Guantanamo]; all of them wear this watch.

Variants edit

Model name Description
F-91W-3, F-91WG-9 Similar to the original F-91W, but including a green and gold trim respectively on the face.[21]
F-91-WC series Neon colors for case, face and strap: orange, blue, green, pink, beige and yellow.[22]
F-91-WM series Metallic colored cases with black straps: grey, army green, silver and gold.
F-91-WS series Translucent straps with muted case colors: blue, pink, white, and grey[23]
F-84W Japanese Domestic Market (JDM) model. Uses the same 593 module, but the case design is more similar to the older F-28W and F-87W. It has lugs instead of an embedded strap.
F-94W Circular icon arrangement in the display.
W59 Black case with rounded corners and blue accents on the face. Waterproof up to 50 meters.
A158W, A159W, A163W, A164W Stainless steel band.
A159WGEA-1 Stainless steel band, gold color.
F-105W, A168W, A168WG, A168WEGM, A168WEM, W-86 Equipped with electroluminescent backlighting instead of the LED backlight in the other variants. Available in black color with a resin strap or in silver or gold colors with a stainless steel bracelet. Slightly different icon arrangement on the display and a thicker case due to the backlight system. Some versions also feature a negative display.
LA680 A smaller variant, marketed towards women

Counterfeits edit

 
Holding the right button for 3 seconds in the main timekeeping mode leads the display to show "CASIo", which is useful to spot a counterfeit model (applicable for newer models of the F-91W and its variants, including F-94W and A158W)

Counterfeits of this watch are very common, despite its low price tag. These counterfeits generally have a lower plastic build quality, narrower LCD viewing angles, louder and higher-pitched beeps, and significantly less accurate timekeeping than genuine models.[24] The newer modules with the green LED light can be tested by holding the right button for over 3 seconds in the main timekeeping mode; this will lead the display to show "CASIo", as a test for authenticity. With the advancement in technology, however, some counterfeit models have also been developed to show this sign, although these are fairly uncommon. This leaves the only method of distinguishing them as assessing the overall build quality, timekeeping accuracy, display viewing angle and the printing on the screen glass.[24][25]

Upgrades edit

References edit

  1. ^ a b Moyer, Phillip (June 15, 2019). "The case of an iconic watch: how lazy writers and Wikipedia create and spread fake 'facts'". KSNV. Retrieved June 19, 2019.
  2. ^ Casio: General Catalog (1984): The Casio Collection. A Superb Selection of Modern Timepieces
  3. ^ "Casio F91W-1: The retro watch with a strange double life". Montredo. February 4, 2020. Retrieved April 19, 2020.
  4. ^ Ariel Adams (April 16, 2017). "An Afternoon In Tokyo With The Man Who Designs Casio G-Shock Watches". [A Blog To Watch. Retrieved July 6, 2019.
  5. ^ "F-91W-1 | Digital | Youth | Timepieces | CASIO". CASIO Official Website. Retrieved February 16, 2022.
  6. ^ a b c "F91W-1 Classic Timepiece". Casio. Retrieved April 27, 2011.
  7. ^ "F91W-1 | Steel Black Digital Watch | CASIO". CASIO Official Website.
  8. ^ . Casio. Archived from the original on May 30, 2011. Retrieved May 22, 2013.
  9. ^ "Manual" (PDF). Casio. Retrieved November 26, 2014.
  10. ^ "Guantánamo Bay files: Casio wristwatch 'the sign of al-Qaida'". The Guardian. April 25, 2011.
  11. ^ "Casio F-91W: The strangely ubiquitous watch". BBC NEWS. April 26, 2011.
  12. ^ "Guantánamo files: How interrogators were told to spot al-Qaida and Taliban members". the Guardian. April 25, 2011. Retrieved April 10, 2019.
  13. ^ James Ball (April 25, 2011). "Guantánamo Bay files: Casio wristwatch 'the sign of al-Qaida'". The Guardian. London.
  14. ^ "USA v. al Qahtani" (PDF). US Department of Defense. November 7, 2005. Retrieved February 27, 2007.
  15. ^ "Combatant status review board for Mohammed Ahmad Said el Edah". The New York Times. October 6, 2004.
  16. ^ a b "Why Am I in Cuba?". Mother Jones. July 12, 2006.
  17. ^ (PDF). October 13, 2004. Archived from the original (PDF) on July 31, 2006.
  18. ^ . National Journal. February 3, 2006. Archived from the original on July 4, 2008.
  19. ^ R. Jeffrey Smith (July 21, 1996). "New Devices May Foil Airline Security". The Washington Post. pp. A01. Retrieved March 14, 2008.
  20. ^ Batya (July 9, 2020). "How did the Casio F91W Become a Terrorist Icon?". Reaper Feed.
  21. ^ "F-91WG-9 | VINTAGE SERIES | Timepieces | CASIO". CASIO Official Website. Retrieved December 12, 2021.
  22. ^ . www.casio.co.uk. Archived from the original on May 30, 2011. Retrieved June 8, 2019.
  23. ^ "Casio International | Timepieces | Digital | F-91WS-2 | CASIO". www.casio-intl.com. Retrieved April 8, 2020.
  24. ^ a b "Comparing a genuine Casio F91-W with a fake". July 2018. Retrieved March 25, 2019.
  25. ^ Nguyen, Khoi (August 31, 2018). "Casio F91W Review - Retro Digital Sport Watch". Gentleman Within (review). Retrieved August 28, 2019.
  26. ^ Castillo, Jose (October 2, 2023), The Sensor Watch, retrieved October 4, 2023
  27. ^ "Sensor Watch". Sensor Watch. Retrieved October 3, 2023.
  28. ^ "Sensor Watch". Crowd Supply. Retrieved October 3, 2023.
  29. ^ "Converting My Casio F-91W to a Sensor Watch - Spencer Bywater". www.spencerbywater.com. Retrieved October 4, 2023.
  30. ^ Aufranc (CNXSoft), Jean-Luc (January 11, 2022). "Microchip SAM L22 board makes Casio F-91W watch more customizable (Crowdfunding) - CNX Software". CNX Software - Embedded Systems News. Retrieved October 4, 2023.
  31. ^ Horsey, Julian (July 22, 2022). "Iconic Casio F-91W watch converted into a smartwatch". Geeky Gadgets. Retrieved October 4, 2023.
  32. ^ Beschizza, Rob (August 14, 2023). "Sensor Watch, a replacement board for the legendary Casio F-91W wristwatch". Boing Boing. Retrieved October 4, 2023.
  33. ^ Lewin, Day (February 24, 2022). "Remoticon 2021 // Joey Castillo Teaches Old LCDs New Tricks". Hackaday. Retrieved October 4, 2023.

External links edit

  •   Media related to Casio F-91W at Wikimedia Commons
  • F91W-1 product page, Casio website

February 12, 2024
casio, digital, watch, manufactured, japanese, electronics, company, casio, introduced, june, 1989, successor, popular, price, long, battery, life, watch, with, resin, case, resin, strapmanufacturercasiotypequartzdisplaydigitalintroducedjune, 1989, contents, s. The Casio F 91W is a digital watch manufactured by Japanese electronics company Casio Introduced in June 1989 1 as a successor of the F 87W 2 it is popular for its low price and long battery life 3 Casio F 91WCasio F 91W 1 watch with a resin case and resin strapManufacturerCasioTypeQuartzDisplayDigitalIntroducedJune 1989 1 Contents 1 Specifications 1 1 Design 1 2 Features 1 3 Water resistance 2 Operation 3 Usage in terrorism 4 Variants 5 Counterfeits 6 Upgrades 7 References 8 External linksSpecifications editDesign edit Designed by Ryusuke Moriai as his first design for Casio 4 the case of the F 91W measures 37 5 by 34 5 by 8 5 millimetres 1 48 by 1 36 by 0 33 in The case is primarily made of resin 5 with a stainless steel caseback and buttons with the manufacturer s module number 593 stamped on the caseback The resin strap is 18 millimetres 0 71 in at the fitting and 22 mm across the widest part of the lugs The total weight is 21 grams 0 74 oz Features edit The F 91W is a chronograph featuring a 1 100 second stopwatch with a count up to 59 59 99 nearly one hour The stopwatch also has the feature to mark net and split time lap Other features include an hourly time beep and a single daily alarm lasting 20 seconds and an annual calendar with adjustment for leap years not supported as the watch does not record the year February is always counted as 28 days 6 The watch uses a faint green LED backlight located to the left of the display for illumination in earlier versions it was an amber microlight According to manufacturer estimates the watch is reported to be accurate to 30 seconds per month 6 The quartz movement designated Module 593 is powered by a single CR2016 3 volt lithium button cell 7 Water resistance edit The watch front is marked Water Resist 6 but Casio reports different values for different variants of the watch The black version F91W 1 8 is 30 meter 3 bar i e 100 feet 44 psi the ISO standard meaning of which is Suitable for everyday use Splash rain resistant NOT suitable for showering bathing swimming snorkeling water related work and fishing Operation edit nbsp Casio F 91W in regular timekeeping mode and using the 24 hour display option The watch is currently set to sound the alarm and hourly chimeThe watch is controlled by three side mounted push buttons The upper left button labeled Light turns on the light cancels the alarm resets the stopwatch or marks the split lap time and is used for selecting settings The lower left button labelled Mode cycles the modes of the watch time display alarm stopwatch and time date adjustment The right button labeled Alarm On Off 24hr is the function button when used it starts and stops the stopwatch changes the settings currently being adjusted or switches between the 12 and 24 hour modes depending on what mode the watch is currently in Pressing all three buttons at the same time will fill all the cells on the LCD until any button is pressed again 9 The time or date is adjusted by pressing the lower left button three times to bring the watch to time adjustment mode The top left button is used to cycle through seconds hours minutes month date day and normal mode The right button is used to adjust the flashing value displayed Unlike any other value the seconds can only be zeroed Should this happen before 30 seconds the watch will zero in at the beginning of the current minute After 30 seconds it will start the next minute as displayed When the adjustments are finished the bottom left button can be pressed once to return the watch to normal mode The watch display shows the day of the week day of the month hour minute seconds and the signs PM in the afternoon or 24H 24 hour clock at all times the alarm signal status bar of vertical lines and the hourly signal status double beep on the hour shown as a bell are present when activated in the alarm mode In stopwatch mode minutes seconds and hundredths of a second are shown Usage in terrorism editFurther information Seton Hall reports Detainees profile nbsp This improvised timer for a time bomb was captured in the early 2000s The US government became suspicious of Afghans who wore Casio watches due to their ability to be used as timers for improvised explosive devices a tactic favored by al Qaeda 10 11 According to secret documents issued to interrogators at Guantanamo Bay obtained 12 and released by The Guardian the Casio F 91W digital watch was declared to be the sign of al Qaeda and a contributing factor to continued detention of prisoners by the analysts stationed at Guantanamo Bay Briefing documents used to train staff in assessing the threat level of new detainees advise that possession of the F 91W and the A159W available online for as little as 4 suggests the wearer has been trained in bomb making by al Qaeda in Afghanistan 13 United States military intelligence officials have identified the F 91W as a watch that terrorists use in constructing time bombs 14 15 16 17 This association was highlighted in the Denbeaux study and may have been used in some cases at Guantanamo Bay 18 An article published in The Washington Post in 1996 reported that Abdul Hakim Murad Wali Khan Amin Shah and Ramzi Ahmed Yousef had developed techniques to use commonly available Casio digital watches to detonate time bombs 19 Casio watches were mentioned almost 150 times in prisoner assessments from Guantanamo 20 On 12 July 2006 the magazine Mother Jones provided excerpts from the transcripts of a selection of the Guantanamo detainees 16 The article informed readers More than a dozen detainees were cited for owning cheap digital watches particularly the infamous Casio watch of the type used by Al Qaeda members for bomb detonators The article quoted Abdullah Kamel Abdullah Kamel Al Kandari When they told me that Casios were used by Al Qaeda and the watch was for explosives I was shocked If I had known that I would have thrown it away I m not stupid We have four chaplains at Guantanamo all of them wear this watch Variants editModel name DescriptionF 91W 3 F 91WG 9 Similar to the original F 91W but including a green and gold trim respectively on the face 21 F 91 WC series Neon colors for case face and strap orange blue green pink beige and yellow 22 F 91 WM series Metallic colored cases with black straps grey army green silver and gold F 91 WS series Translucent straps with muted case colors blue pink white and grey 23 F 84W Japanese Domestic Market JDM model Uses the same 593 module but the case design is more similar to the older F 28W and F 87W It has lugs instead of an embedded strap F 94W Circular icon arrangement in the display W59 Black case with rounded corners and blue accents on the face Waterproof up to 50 meters A158W A159W A163W A164W Stainless steel band A159WGEA 1 Stainless steel band gold color F 105W A168W A168WG A168WEGM A168WEM W 86 Equipped with electroluminescent backlighting instead of the LED backlight in the other variants Available in black color with a resin strap or in silver or gold colors with a stainless steel bracelet Slightly different icon arrangement on the display and a thicker case due to the backlight system Some versions also feature a negative display LA680 A smaller variant marketed towards womenCounterfeits edit nbsp Holding the right button for 3 seconds in the main timekeeping mode leads the display to show CASIo which is useful to spot a counterfeit model applicable for newer models of the F 91W and its variants including F 94W and A158W Counterfeits of this watch are very common despite its low price tag These counterfeits generally have a lower plastic build quality narrower LCD viewing angles louder and higher pitched beeps and significantly less accurate timekeeping than genuine models 24 The newer modules with the green LED light can be tested by holding the right button for over 3 seconds in the main timekeeping mode this will lead the display to show CASIo as a test for authenticity With the advancement in technology however some counterfeit models have also been developed to show this sign although these are fairly uncommon This leaves the only method of distinguishing them as assessing the overall build quality timekeeping accuracy display viewing angle and the printing on the screen glass 24 25 Upgrades editSensor Watch an unofficial open source hardware circuit board replacement for original F 91W and A158W watches based on ARM Cortex M0 microchip with various additional sensors 26 27 28 29 30 31 32 33 References edit a b Moyer Phillip June 15 2019 The case of an iconic watch how lazy writers and Wikipedia create and spread fake facts KSNV Retrieved June 19 2019 Casio General Catalog 1984 The Casio Collection A Superb Selection of Modern Timepieces Casio F91W 1 The retro watch with a strange double life Montredo February 4 2020 Retrieved April 19 2020 Ariel Adams April 16 2017 An Afternoon In Tokyo With The Man Who Designs Casio G Shock Watches A Blog To Watch Retrieved July 6 2019 F 91W 1 Digital Youth Timepieces CASIO CASIO Official Website Retrieved February 16 2022 a b c F91W 1 Classic Timepiece Casio Retrieved April 27 2011 F91W 1 Steel Black Digital Watch CASIO CASIO Official Website F 91W 1XY Casio Archived from the original on May 30 2011 Retrieved May 22 2013 Manual PDF Casio Retrieved November 26 2014 Guantanamo Bay files Casio wristwatch the sign of al Qaida The Guardian April 25 2011 Casio F 91W The strangely ubiquitous watch BBC NEWS April 26 2011 Guantanamo files How interrogators were told to spot al Qaida and Taliban members the Guardian April 25 2011 Retrieved April 10 2019 James Ball April 25 2011 Guantanamo Bay files Casio wristwatch the sign of al Qaida The Guardian London USA v al Qahtani PDF US Department of Defense November 7 2005 Retrieved February 27 2007 Combatant status review board for Mohammed Ahmad Said el Edah The New York Times October 6 2004 a b Why Am I in Cuba Mother Jones July 12 2006 Summary of Evidence memo pdf prepared for Sabri Mohammed Ebrahim Al Qurashi s Combatant Status Review Tribunal page 216 PDF October 13 2004 Archived from the original PDF on July 31 2006 Empty Evidence National Journal February 3 2006 Archived from the original on July 4 2008 R Jeffrey Smith July 21 1996 New Devices May Foil Airline Security The Washington Post pp A01 Retrieved March 14 2008 Batya July 9 2020 How did the Casio F91W Become a Terrorist Icon Reaper Feed F 91WG 9 VINTAGE SERIES Timepieces CASIO CASIO Official Website Retrieved December 12 2021 Casio Collection Timepieces Products CASIO www casio co uk Archived from the original on May 30 2011 Retrieved June 8 2019 Casio International Timepieces Digital F 91WS 2 CASIO www casio intl com Retrieved April 8 2020 a b Comparing a genuine Casio F91 W with a fake July 2018 Retrieved March 25 2019 Nguyen Khoi August 31 2018 Casio F91W Review Retro Digital Sport Watch Gentleman Within review Retrieved August 28 2019 Castillo Jose October 2 2023 The Sensor Watch retrieved October 4 2023 Sensor Watch Sensor Watch Retrieved October 3 2023 Sensor Watch Crowd Supply Retrieved October 3 2023 Converting My Casio F 91W to a Sensor Watch Spencer Bywater www spencerbywater com Retrieved October 4 2023 Aufranc CNXSoft Jean Luc January 11 2022 Microchip SAM L22 board makes Casio F 91W watch more customizable Crowdfunding CNX Software CNX Software Embedded Systems News Retrieved October 4 2023 Horsey Julian July 22 2022 Iconic Casio F 91W watch converted into a smartwatch Geeky Gadgets Retrieved October 4 2023 Beschizza Rob August 14 2023 Sensor Watch a replacement board for the legendary Casio F 91W wristwatch Boing Boing Retrieved October 4 2023 Lewin Day February 24 2022 Remoticon 2021 Joey Castillo Teaches Old LCDs New Tricks Hackaday Retrieved October 4 2023 External links edit nbsp Media related to Casio F 91W at Wikimedia Commons F91W 1 product page Casio website Retrieved from https en wikipedia org w index php title Casio F 91W amp oldid 1203336588, wikipedia, wiki, book, books, library,

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