So I’ve decided that I’d like the ability for the Arduino / Silvia Duetto to be able to maintain the time and consequently warm her belly up at specific times during the day. As any Silvia owner knows, it is extremely important to have both Silvia’s boiler as well as the group-head and portafilter up to temperature prior to pulling a shot.
I selected the Maxim / Dallas Semiconductors DS3232 as a suitable real-time clock (RTC). This handy little device has a built-in crystal (XTAL) oscillator and most importantly operates over an I2C bus. As pin space is limited on the Arduino Pro Mini, both the display I’ve selected and now this RTC have the ability to share the same two data pins. Moreover this RTC is rated for industrial temperatures at -40°C to 85°C and contains a built in temperature sensor to provide temperature compensation to the device (as the heat will fluctuate inside Silvia, so will the resonant frequency of the XTAL).
Maxim / Dallas Semiconductors also have a great sample program which means I got 4 of these chips for free! I’m off to wire up a test circuit. More to come soon!