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#762 HamClock

Exploring HamClock, the kiosk-style application that displays real time space weather, radio propagation models, operating events and other information particularly useful to the radio amateur. Trying it on macOS, Ubuntu and Raspberry Pi. With the Raspberry Pi, hook up the BME280 environmental sensor and satellite, alarm, and timer indicators. As of 2026, HamClock has reached end-of-life, so I also cover potential replacements.

Build

Notes

I learned about Geochron clocks (analog and digital) on Ham Radio Workbench 230. These are beautiful displays of the current time over a live map of the earth, and support overlays for all manner of interesting details.

They are expensive though! I did find out though (via a tip from Mike Deal N7URH) that there is an open source alternative specifically designed for amateur radio called HamClock.

HamClock is a kiosk-style application that provides real time space weather, radio propagation models, operating events and other information particularly useful to the radio amateur.

HamClock was introduced in an October 2017 QST article and continues to be maintained and expanded. It supports a range of platforms:

  • ESP8266 - the original design, still available but no longer maintained
  • Raspberry Pi
  • Linux-style systems
  • macOS

Feb-2026 Update

In early 2026, the community of HamClock enthusiasts was sad to learn that the creator of HamClock was now an SK and that the HamClock site announced:

HamClock has reached end-of-life, the last release is version 4.22. All HamClocks will cease to function in June 2026. Thank you for your interest. Elwood Downey, WB0OEW, ecdowney@clearskyinstitute.com

So what is the future of HamClock? In the immediate future, HamClock services will start to degrade, as backend dependencies go offline.

I have captured a full archive of HamClock front-end releases at https://github.com/tardate/ESPHamClock.

A few projects that are potential successors for HamClock include:

macOS

I’m running macOS with an Apple Silicon M1 chip, so it is an obvious place to start. Can we run HamClock? Yes!

Installing XQuartz (for XWindows support) with brew:

brew install --cask xquartz

Then run the installation steps per the documentation:

curl -O https://www.clearskyinstitute.com/ham/HamClock/ESPHamClock.zip
unzip ESPHamClock.zip
cd ESPHamClock
make -j 4 hamclock-800x480
sudo make install

The sources can then be removed:

cd ..
rm -fR ESPHamClock
rm ESPHamClock.zip

To run HamClock, first start XQuartz

open -a XQuartz

Then within XQuartz, choose “Applications > Terminal”, and run the “hamclock” command in the xterm

macos-run-hamclock

After entering call sign, lat lng options etc, HamClock starts and I can start to play with the display options - see the user guide https://www.clearskyinstitute.com/ham/HamClock/HamClockKey.pdf.

macos-hamclock01

Nice! Works great.

Ubuntu

I also routinely use Ubuntu (currently version 24.04). Let’s try.

Make sure pre-requisites are installed:

sudo apt install curl make g++ xorg-dev xdg-utils

Run the installation steps per the documentation (this time a slightly larger 1600x960):

curl -O https://www.clearskyinstitute.com/ham/HamClock/ESPHamClock.zip
unzip ESPHamClock.zip
cd ESPHamClock
make -j 4 hamclock-1600x960
sudo make install

The sources can then be removed:

cd ..
rm -fR ESPHamClock
rm ESPHamClock.zip

Run HamClock from the console:

hamclock

ubuntu-hamclock01

Nice! Also works great.

Raspberry Pi

I have an old Raspberry Pi 1 Model B+. Current documentation recommends an RPi model 4b with 1 GB RAM. Maybe it is possible to use a Raspberry Pi B+?

I grabbed a copy of the latest Raspberry Pi OS and ran the HamClock RPi installation per the docs:

curl -O https://www.clearskyinstitute.com/ham/HamClock/install-hc-rpi
chmod u+x install-hc-rpi
./install-hc-rpi

The installation took a very long time (I left it for an hour or so), but completed successfully. After installation, start from the command line:

hamclock

HamClock runs fine, albeit a little sluggishly.

Rebuilding for Headless operation

I removed the previous installation:

rm -fr ESPHamClock
rm ~/Desktop/hamclock.desktop
sudo rm /usr/local/bin/hamclock*

Then downloaded the latest sources to build a web-only 1600x960 version:

$ wget <https://www.clearskyinstitute.com/ham/HamClock/ESPHamClock.zip>
$ unzip  ESPHamClock.zip
$ cd ESPHamClock
$ make help

The following targets are available (as appropriate for your system)

    hamclock-800x480          X11 GUI desktop version, AKA hamclock
    hamclock-1600x960         X11 GUI desktop version, larger, AKA hamclock-big
    hamclock-2400x1440        X11 GUI desktop version, larger yet
    hamclock-3200x1920        X11 GUI desktop version, huge

    hamclock-web-800x480      web server only (no local display)
    hamclock-web-1600x960     web server only (no local display), larger
    hamclock-web-2400x1440    web server only (no local display), larger yet
    hamclock-web-3200x1920    web server only (no local display), huge

    hamclock-fb0-800x480      RPi stand-alone /dev/fb0, AKA hamclock-fb0-small
    hamclock-fb0-1600x960     RPi stand-alone /dev/fb0, larger, AKA hamclock-fb0
    hamclock-fb0-2400x1440    RPi stand-alone /dev/fb0, larger yet
    hamclock-fb0-3200x1920    RPi stand-alone /dev/fb0, huge

Optional command line variables which may be set before the desired target:
    FB_DEPTH=16 or 32         - Specify a given frame buffer pixel size (default is 32 on all but fb0)
    WIFI_NEVER=1              - Disable WiFi fields in setup (already the default on all but fb0)

$ make -j 4 hamclock-web-1600x960
$ sudo make install

And then startup in the background:

$ hamclock &
[1] 1202
$

I am using the default ports and the Raspberry Pi is on 192.168.10.36, so I can now access hamclock interfaces

The web view:

rpiweb-01a

To start this automatically on each boot, run crontab -e then add the following as the last line:

@reboot /usr/local/bin/hamclock

When running headless, it wasn’t clear how to access the configuration screens reliably. I’ve found the best approach is to choose “Restart HamClock” from the HamClock menu, and staying on the web page will present an opportunity to go into configuration.

Exercising GPIO Support

Since it is running on the Pi, I can play with some of the GPIO support. This requires first visiting setup page 4 and turning on “GPIO”.

The features I’ve enabled include:

  • Satellite up LED indicator
  • BME280 environmental sensor
  • On-the-air button
  • Countdown timer indicators and start/reset button
  • Alarm indicator and cancel button

I’ve redrawn the schematic with Fritzing, see HamClock.fzz.

HamClock_schematic

HamClock_bb

Wired up an breadboard for testing:

HamClock_bb_build

Note: I subsequently made a DIY hat to mount the circuit directly on the Pi. See LEAP#831 HamClock Hat.

Satellite Up Indicator

I am testing the “Satellite up” indicator per the user guide:

  • Output terminal SA_1 (GPIO20, pin 38) indicates satellite visibility from DE.
  • Normally low
  • Cycles high at 1Hz for 1 minute before rise
  • Stays high during the pass
  • Cycles at 2 Hz during the last minute
  • Stays low again after set.

I just tested it with a ACS3 satellite pass near my location (Singapore 1.3521° N, 103.8198° E). Works perfectly as described!

satellite_up01

Watching the screen for satellites overhead …

satellite_up02

BME280 Environmental Sensor

Additional pre-requisites for BME280 support:

  • Run sudo raspi-config and enable ARM I2C support under “3. Interface Options”
  • Verify the /dev/i2c-1 device is present
  • HamClock setup page 4: set I2C file to /dev/i2c-1

The BME280 is wired to the Raspberry Pi I²C bus on pins 3 (SDA1) & 5 (SCL1), while also taking 3.3V power and ground.

After restarting HamClock, I can verify the sensor results being collected with the get_sensors API endpoint:

$ curl "http://192.168.10.36:8080/get_sensors.txt"
#   UTC ISO 8601      UNIX secs I2C  Temp,C   P,hPa   Hum,%  DewP,C
2026-02-09T07:38:23Z 1770622703  76   25.36 1003.45   33.27    8.04
2026-02-09T07:38:28Z 1770622708  76   25.35 1003.52   33.30    8.04
2026-02-09T07:38:34Z 1770622714  76   25.30 1003.49   33.34    8.02
2026-02-09T07:38:41Z 1770622721  76   25.28 1003.51   33.29    7.98
2026-02-09T07:38:54Z 1770622734  76   25.28 1003.46   33.55    8.09
2026-02-09T07:38:54Z 1770622734  76   25.29 1003.44   33.56    8.11
2026-02-09T07:39:05Z 1770622745  76   25.25 1003.46   33.86    8.20
2026-02-09T07:39:18Z 1770622758  76   25.07 1003.42   34.16    8.17
2026-02-09T07:39:33Z 1770622773  76   25.15 1003.44   34.10    8.22
2026-02-09T07:39:51Z 1770622791  76   25.09 1003.48   34.31    8.25
2026-02-09T07:40:13Z 1770622813  76   25.17 1003.41   33.98    8.18

Readings from the BME280 can be configured to display in the top panels, for example here is the temperature in pane 1, and BME readings in the narrow, right-most pane 4:

bme-01

On-the-air Button

The “On the Air” button simply signals OTA status to the HamClock.

This simply requires wiring a button to ground/pull-down OA_1 (GPIO21, pin 40)

The status is displayed in the call sign/title area:

ota-01

Countdown Timer Indicators and Start/Reset Button

The countdown time is configured by clicking on the stopwatch under the UTC seconds in the main screen. I have a 2 minute timer set:

countdown-alarm-01

The countdown hardware comprises:

  • green LED & resistors
    • on during countdown
    • blinks during the last 1 minute of the count down
    • controlled by the low-side signal CD_3 (GPIO19, pin 35)
  • red LED & resistors
    • on during the last 1 minute of the count down
    • blinks for 30 seconds after the count down is complete
    • controlled by the low-side signal CD_2 (GPIO13, pin 33)
  • push-button
    • starts or resets the count down
    • ground/pull-down CD_4 (GPIO26, pin 37)

countdown-02

Alarm Indicator and Cancel Button

Daily and one-time alarms are configured by clicking on the stopwatch under the UTC seconds in the main screen.

countdown-alarm-01

The alarm hardware comprises:

  • yellow LED & resistors
    • on when alarm goes off
    • controlled by the high-side signal AL_1 (GPIO6, pin 31)
  • push-button
    • starts or resets the count down
    • ground/pull-down AL_2 (GPIO5, pin 29)

NB: I did however discover that the alarm indicator GPIO was not being correctly set for output. I fixed that with a small code change, see my PR.

When the alarm goes of it is displayed in data pane 2:

alarm-03

And the LED lights up. The push-button can be used to cancel the alarm:

alarm-02

Credits and References

About LEAP#762 RadiomacOSUbuntuRaspberry PiBME280

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

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LEAP is my personal collection of electronics projects - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting.

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