MorningTown: A silent alarm clock

Description

MorningTown is a silent alarm clock system for a Raspberry Pi Pico W.

At 7:15am, it lights a single green LED. At 8am, it additionally lights a red LED. Around midday, it turns them both off. It does literally nothing else. Oh, apart from synchronising the Pico's real-time clock using NTP.

Why???

Awareness of the exact time is bad for your sleep. If you're having trouble getting to sleep, knowing how late it is only increases your stress level, making it even harder to sleep. Similarly, knowing that your alarm will go off shortly can prevent you from relaxing in the morning, and grabbing a valuable few minutes' extra sleep.

All that you really need is an indicator of whether or not it's a sensible time to get up, or whether you should go back to sleep. That's all that MorningTown will give you.

In contrast to a clock radio or "artificial sunrise" lamp, there is no danger of disturbing any other beings who share the room and may run on different schedules.

Obviously, you should set an audible alarm clock for important wake-up calls. But, in combination with regular sleep hygiene, two LEDs might be all you need to synchronise your sleep pattern!

Hardware

You'll need a Raspberry Pi Pico W. Solder red and green LEDs to GPIOs 21 and 22 respectively, each with a 1.5 kOhm series resistor (you won't need much brightness). There is a ground pad conveniently placed between the two pins.

Circuit diagram

(Hopefully your soldering is a little neater than mine).

Optionally solder a small button between GPIO 16 and GND. This will be a test button for checking the device is working properly (not illustrated above).

You can use other GPIOs if you prefer - just change the definitions of LED_RED, LED_GREEN and TEST_BUTTON in morningtown.c. The positions of 16, 21 and 22 just happen to work well for the geometry of my own nightstand.

Software

Edit compile to set the path to the Pico SDK, as well as your WLAN name and password.

Set your offset from UTC in ntp_client.h, e.g. if you live in time zone UTC+1:

#define UTC_OFFSET_SEC 3600

Sorry, there's no automatic handling of daylight savings yet.

To set different wake-up times, edit routine check_clock() in morningtown.c.

Run compile, then copy build/morningtown.uf2 to the Pico.

Operation

Connect the Pico to any USB power supply. All three LEDs (red, green and the one on Pi board itself) will light briefly. The device will then attempt to connect to the WLAN and synchronise its clock. During this phase, the red LED will be lit continuously and the board LED will light as long as the WLAN is connected. Once an NTP reply is received, all the LEDs will go dark until morning.

When the (optional) test button is pressed (and held), the board LED will indicate a current WLAN connection, the green LED will indicate that NTP is synchronised, and the red LED (hopefully not lit) indicates some kind of error condition.

Licence

MorningTown is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

MorningTown is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with MorningTown. If not, see http://www.gnu.org/licenses/.

About the name

It's like a railway signal for your sleep:

Somewhere there is sunshine
Somewhere there is day
Somewhere there is Morning town
Many miles away

The Seekers, 1966