Prevent your computer from going to sleep

If you have problems with your PC locking or going to sleep, caffeine will keep it awake. It works by simulating a keypress once every 59 seconds, so your machine thinks you're still working at the keyboard, so won't lock the screen or activate the screensaver.

The icon is shown above - it's the leftmost one in the task tray, and this is all you see. Double-clicking the icon empties the coffee pot (that's what the icon is) and temporarily disables the program. Double-clicking it again refills the pot, and will keep your machine awake.

By default the app starts enabled, and works every 59 seconds. There are some command line switches you can use to alter this behaviour:

• xx - where xx is a number which sets the number of seconds between simulated keypresses. This must be the first text on the commandline
• -startoff - application starts disabled.
• -exitafter:xx - application will terminate after xx minutes
• -activefor:xx - application will become inactive after xx minutes
• -inactivefor:xx - application will become active after xx minutes
• -appexit - terminates current running instance of application
• -appon - makes the current running instance of the application active
• -appoff - makes the current running instance of the application inactive
• -apptoggle - toggles the running state of the current running instance of the application
• -apptoggleshowdlg - toggles the running state, and shows dialog
• -replace - closes the current running instance, replacing it
• -noicon - does not show a task tray icon
• -useshift - simulate the shift key instead of F15
• -showdlg - shows a dialog indicating whether caffeine is active
• -ontaskbar - show a task bar button (use with -showdlg)
• -allowss - prevent sleep, but allow the screensaver to start
• -key:xx - simulate using virtual key code xx
  Note: the codes on the linked page are in Hex, convert them to decimal for use with this parameter
• -keypress - simulate a full key press, not just a key up event
• -oldicons - use more colourful tray icons
• -darkicons - use icons which work better for dark-on-light colour schemes
• -watchwindow:xx - active only when a window with xx in the title is found
• -activehours:....xxxxxxxx.... - put 24 . or x characters - which indicate from hour 0 to hour 23 of the day. Caffeine will be active only in hours with an x

Compatibility

Caffeine works by simulating an F15 key up event every 59 seconds. Of all the key presses available, F15 is probably the least intrusive, and least likely to interfere with your work.

Yesterday, my colleague Anthony ran an informative tutorial that does a good job covering two ways to keep your Mac from sleeping, dimming or showing a screensaver: one is based on a little bit of Terminal magic and the other involves using a free of charge utility, called Caffeine.

However, Caffeine might interfere with some apps:

• PowerPoint uses the F15 keypress to pause video in a slide
• Google Docs/Sheets
• Smartsheet
• Terminal emulation, e.g. Putty

1. Caffeine is used to prevent a computer from going into screensaver, sleep, suspend or hibernate modes.Caffeine Portable Online Installer will download Caffeine and set it up so that it it compatible with the Portable Apps Platform.
2. Caffeine demo v0.9.2 Linux Edition has been released today mainly fixing a number of bugs and implementing fixes for Oculus Rift. Caffeine 2014 demo 0.92 - linux demo Caffeine 2014 Demo v0.92 - Windows 64-Bit.
3. Caffeine; Versions; Download; Caffeine Prevent your computer from going to sleep. If you have problems with your PC locking or going to sleep, caffeine will keep it awake. It works by simulating a keypress once every 59 seconds, so your machine thinks you're still working at the keyboard, so won't lock the screen or activate the screensaver.

If you think any of these might cause you a problem, set the -useshift command line parameter.

Video

Caffeine user humancar2n has put together a short YouTube video showing how the app works.

Mac version

Do you need this functionality on your Mac? Lighthead Software have written a separate app, also named Caffeine, which can help you out.

Versions

v1.90 - October 2020

-darkicons command line option added

-activehours command line option added

Tooltip replaced with a new one which works more reliably

Menu appearance updated

v1.81 - May 2020

Bug with the -watchwindow command line fixed

v1.80 - January 2020

v1.64 - September 2017

Option for old icons added, 'cos not everyone likes the new ones

v1.63 - February 2017

Download Caffeine App

Icons updated slightly to show up better on a white background.

v1.62 - April 2016

New icons, designed by Rubén Gómez Radioboy

v1.61 - October 2015

Fixed bug with app not going active/inactive correctly when a timed period elapsed

v1.60 - July 2013

New command line options:

• -allowss
• -ontaskbar
• -apptoggleshowdlg
• -key:xx
• -keypress

Added menu items to go Active/Inactive

Type in About box corrected

-apptoggle will re-show the dialog if it was originally shown

v1.50 - November 2010

New command line options:

• -inactivefor
• -showdlg
• -apptoggle

Simulated keypress changed from right context menu key to F15 as this is likely to be even less intrusive.

v1.40 - July 2009

New command line options:

• -replace
• -noicon
• -useshift

Sony sound forge 8.0 keygen free download. Hovering over the tray icon now shows the status of the app

v1.35 - May 2009

Simulated keypress changed from shift to the right context menu key (at the suggestion of Kevin Kleinfelter) as this is likely to be less intrusive.

v1.30 - February 2009

Command line switches added to terminate the app after x minutes, disable the app after x minutes, and enable or disable the currently running instance of the app

v1.20 - March 2008

Command line switches added to set the interval and to start disabled

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