Purchase a kit from the Schematix Store: Click here
Programming and wiring guides:
Download the programming guide: click here
Download the wiring guide: click here
Specifications of the Smart Coffee board:
Power in: 100~240VAC
On board DC power supply: 5VDC, 2A
On board 3.3V power supply: 1A
On board, Solid-Sate relays 100~240VAC live outputs:
2x Boiler element (10A)
1x Pump (10A)
2x Programmable relays (usually connected to solenoid valves) (1A)
Total combined output current limit from relays: 20A
Element 1, and Pump combined max current: 10A
Element 2, RLY1, and RL2 combined max current: 10A
7x 5VDC relay control outputs: (used to control external relays for high current loads)
2x Boiler element
1x Pump
4x Programable relays
Fuse:
2x 5x20mm, 10A
ESP32:
Model: 30pin Development Board
Quantity required: 2
Purchasing link: https://s.click.aliexpress.com/e/_DFc08KN
Inputs/Outputs:
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4/6 wire Load Cell Input
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I2C display screen interface
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2x Pressure transducer inputs
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2x Boiler water level detection probes
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Brew Switch input
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Espresso mode selection input
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Reservoir water level detection options:
Reservoir touch-sensitive probe (for detecting water)
Reservoir float switch (compatible with NO and NC switches)
Ultrasonic water level detection
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Ultrasonic distance sensor (for measuring water level inside a reservoir tank)
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2x MAX31865 temperature sensors (compatible with 2, 3, and 4 wire probes. PT100 and PT1000 series compatible)
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6x User programable GPIO pins (M1, M2, S1, S2, S3, and PT3) write your own code to make use of these pins to really customize your coffee experience
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7x 5VDC relay control outputs: (used to control external relays for high current loads)
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2x Boiler element
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1x Pump
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4x Programable relays
Smart Coffee Software Features:
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Single and Dual boiler compatible with a single group head
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PID and PWM logic boiler control
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Boiler target can be programmed as Temperature or Pressure
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Boiler water level probes (used to trigger a refill when required)
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Display metric units (kPa, Celsius, grams, mls) or imperial units (PSI, Fahrenheit, Ounces, fluid ounces)
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Pre-Infusion cycle for every coffee extraction (3 stages consisting of: Prime the system > Cycle pump on/off > Extract coffee until the programmed amount has been dispensed)
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Momentary or latching switch compatible for Brew and Espresso mode switches
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Pressure transducer inputs to control/monitor pressure
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Programmable pressure safety limits (machines shuts down when safety limits are exceeded)
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Thermocouple temperature sensors to monitor any temperature on the machine
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Programmable pressure safety limits (machines shuts down when safety limits are exceeded)
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Espresso shot output (when espresso mode is activated by the user)
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- Espresso shot timer
- Espresso shot by weight target (requires loadcell)
- Espresso shot by volume target (requires flow meter)
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Pause boiler refill (pauses a boiler refill if an espresso extraction is currently taking place)
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Ultrasonic distance sensor (used for machines with a reservoir tank to measure the water level)
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Reservoir empty standby mode (prevents the machine from operating until the reservoir is refilled)
Purchase Sensors and Hardware:
ESP32:
Model: 30pin Development Board
Quantity required: 2
Purchasing link: https://s.click.aliexpress.com/e/_DFc08KN
Pressure transducer:
Max voltage input from pressure transducer: 5V
Recommended signal range: 0.5 to 4.5V
Recommended pressure rating: 200 kPa (0.2mPa)
(pressure rating should be at minimum 20% higher than your running pressure)
Purchasing link: https://s.click.aliexpress.com/e/_DkQsvxd
Optional G1/4 to 1/4BSP thread adapter (select type 2): https://s.click.aliexpress.com/e/_DdueKDl
Right angle adapter: https://s.click.aliexpress.com/e/_DE8J34X
Display screen:
Model: OLED SH1107
Interface: I2C
Pixels: 128x128
Input power: 5V
Purchasing link: https://s.click.aliexpress.com/e/_DlH1C43
Load cell:
Weight rating: 1kg
Wiring: 4wire
Purchasing link: https://s.click.aliexpress.com/e/_DdDwihl
4 Pin pogo connector:
Purchasing link: https://s.click.aliexpress.com/e/_DB2fN7N
Small size flow meter:
Model: USN-HS06P
Voltage: 5V
Barb Size: 5mm OD
Flow range: 30 ~ 150ml/min
Purchasing link: https://s.click.aliexpress.com/e/_DCCjQh5
Medium-size flow meter:
Model: USN-HS06PS
Voltage: 5V
Barb size: 7mm OD
Flow range: 0.1 ~ 1.5L/min
Purchasing link: https://s.click.aliexpress.com/e/_DFVTRbV
High-pressure Gicar flow meter:
Purchasing link: https://s.click.aliexpress.com/e/_Dlr1vgB
Thermocouple:
Compatible wiring: 2/3/4 wire
Type: PT100 and PT1000 compatible
Purchasing link for screw mount type: https://s.click.aliexpress.com/e/_DkV2nuB
Purchasing link for threaded mount type: https://s.click.aliexpress.com/e/_DD0nYYx
Ultrasonic Distance Sensor:
Model: A02YY
Output signal: PWM
Input: 5V
Purchasing link: https://s.click.aliexpress.com/e/_DFYOL3z
Switches:
Chrome LED lit momentary switch: https://s.click.aliexpress.com/e/_Dd0BleB
(can be used for the brew and espresso mode switches)
USB panel mount connector:
Purchasing link: https://s.click.aliexpress.com/e/_DksmHhh
Shielded multi-core cable:
28AWG, 2meter
Purchasing link: https://s.click.aliexpress.com/e/_DkdDW87
M3 Brass standoff:
These are handy for mounting the PCB
Purchasing link: https://s.click.aliexpress.com/e/_Dn3mUKB
Bug reporting and suggestions:
If you happen to find a bug in the software. Please write a comment below and describe the issue with as much detail as possible.
Updates for Smart Coffee:
Change log and updates:
- V1.0 Base version published
- v1.1 Added Shot Stopwatch feature to time the duration of brewing
PCB Dimensions:
Width: 101mm (3.97")
Length: 166mm (6.53")
Mounting hole size: 3.7mm
(click image to enlarge)
