periodic wakeup from suspend

hosts/yodaHedgehog/configuration.nix

@@ -50,7 +50,7 @@
       #../../modules/ntfs.nix
       #../../modules/veracrypt.nix
       #../../modules/btrbk
-      #../../modules/spin-down.nix # TODO
+      #../../modules/spin-down.nix
 
       ../../modules/btrfs-scrub.nix
       ../../modules/btrfs-mount-options.nix

hosts/yodaHedgehog/host-specific.nix

@@ -1 +1,31 @@
-{}
+{ config, pkgs, ... }:
+
+{
+  # Suspend system:
+  #   sudo systemctl suspend
+
+  # Power consumption:
+  #   2.4W powered off
+  #   2.6W suspended, with 1 RAM, 1 SSD
+
+  # journalctl -u regular-wakeup
+
+  systemd.timers."regular-wakeup" = {
+    wantedBy = [ "multi-user.target" ];
+    timerConfig = {
+      OnCalendar = [
+        # Testing
+        "Sun 16:15:00"
+        # Daily
+        # *-*-* 00:00:05
+      ];
+      WakeSystem = true;
+      };
+   };
+  systemd.services."regular-wakeup" = {
+    script = ''
+      set -eu -o pipefail
+      printf '%s%s\n' 'Wokeup at ' "$(date)"
+    '';
+  };
+}