The Mars Mean-Solar-Day Clock displays local solar time for any location on Mars.
Preface:
A day on Mars is a little longer than on Earth, about 24 hours and 37 minutes.
The oscillator circuit presented here produces a frequency of 58.3947 Hz, which has the same ratio to 60Hz as the length
of a Mars' mean-solar-day to Earth's solar-day, namely 1.0274913:1.
The output of the quartz oscillator is fed to the input of the 4059. The output of
the 4059 is applied to the flip-flop (IC2B) - at Q of IC2B we have a nice 50/50 rectangle signal.
This clock signal is then fed into the clock module.
The timebase:
Timebase generation begins with the 2.4576-MHz pi-network oscillator formed by the quartz crystal and the U1
inverter. The resulting squarewave is applied to the 4059 programmable divide-by-n counter (set to a division by 21043).
The output of the 4059 divider is applied to a flip flop (wired as divide-by-2)
to produce a nice 50% duty-factor squarewave at the desired 58.3947 Hz.
The 4059 (IC3) requires a reset at power-up: This is accomplished with IC1B.
The presets of the 4059 (J1-J16), the mode set Ka, Kb and the latch enable LE are either wired to VCC or GND. Kc is
connected to U1B to provide a nice power-up reset for the 4059.
The 4059 is set to "divide-by-n mode 8" (see the datasheet for details):
n = 8*(1000 + 15*100 + 13*10 + 0*1) + 3 = 21043
The clock:
Here is the clock schematic with the MM5387! If you can't get a MM5387, the LM8361 is the same IC.
The 7-segment displays have a common kathode - see the schematic for the pin assignment for a common display.
The current thru the LED's is regulated with a LM337. Use R3 (1k potentiometer) for brightness adjustment.
I used a red/green dual-LED for AM/PM display - you can use 2 regular LED's aswell. The LM5387 is just wired as
clock, not as alarm-clock. See the PDF datasheet below for more details. If you want to add a seconds-LED, just
wire a LED to pin 39.
Time on Mars - Sunrise, sunset, Earth-rise and Earth-set on Mars
