Meadow can be put into a power-saving sleep state. In this state, your code stops executing and reduces the power draw to only what is required to recover from being in a sleep state. After resuming from a sleep state, your code will resume executing where it left off.
To put the Meadow into sleep mode, call Sleep on the current platform OS object and providing either a TimeSpan or a DateTime. If you provide a TimeSpan, Meadow will sleep for that duration.
// Put Meadow to sleep for 5 seconds.
Device.PlatformOS.Sleep(TimeSpan.FromSeconds(5));
If you provide a DateTime, Meadow will sleep until that time.
In order for this to work properly, you must set the current date via the Device.PlatformOS.SetClock method.
Device.PlatformOS.SetClock(new DateTime(2022, 10, 19, 21, 58, 27));
...
// Put Meadow to sleep until this time tomorrow.
Device.PlatformOS.Sleep(DateTime.Now.AddDays(1));
Sleep-related events
Additionally, you can respond to the sleep state changes in application lifecycle events, specifically BeforeSleep and AfterWake. BeforeSleep is called right before your application goes into sleep mode. And AfterWake is called right after Meadow resumes from sleep but before your code resumes.
These are exposed as events on the Device.PlatformOS object and can have event handlers added to them like any standard .NET event.
Device.PlatformOS.BeforeSleep += () => {...};
Device.PlatformOS.AfterWake += () => {...};
RC1 known issue
Note that there is a bug in the RC1 Meadow OS release where writing to the console output immediately after waking from sleep can cause your app to get stuck. To work around this, avoid writing to the console immediately after waking by adding a small delay before the first logging call.
Device.PlatformOS.AfterWake += () =>
{
// RC1 known issue workaround: small delay to avoid locking up app.
Thread.Sleep(TimeSpan.FromMilliseconds(500));
Resolver.Log.Info("Device has returned from sleep mode");
};