---

**Controlling an Espresso Machine**
* This project was undetaken to repair a faulty Delonghi Cafe Venezia Espresso Machine.
* The Cafe Venezia is a "pump" machine, with "coffee" and "steam" modes.
* Heat is controlled by two snap action disc thermostats, 95C for coffee, 125C for steam.
* The thermostats are somewhat light duty for the 1100 watt boiler
* Consequently, they fail after several years if use.
* This project replaces thermostats with relays controlled by an AVR ATTiny24 .
* Boiler temperature is monitored by a type K thermocouple through an Analog Devices ADC595 thermocouple interface.
* Power to the relays is interlocked through a 130C thermostat serving as a safety shutdown.
* MCU and ADC595 are powered with 5V using a 9V "wall wart" through a 78L05 5V regulator.
* The project was built with "Programmer's Notepad 2"
* The MCU was programmed using the SPI se-ri-@l bus.

*AVR ATTiny 24
*Type K thermocople connects to an Analog Devices ADC595 thermocouple interface
*The ADC595 outputs 10mV/degC and wires directly to PA0, pin 13.
*Analog to Digital Conversions are triggered at a 2Hz rate by Timer1.
*To ensure clean conversions, the ADC Noise Reduction feature is used.
*
*Outputs to Opto Isolators:
* PB0 - Relay 1
* PB1 - Relay 2
*
* Temperature thresholds:
* 1: Off @ 97C
* 1: On @ 95C
* 2: Off @ 123C
* 2: On @ 121C

---