Purchase a kit from the Schematix Store: Click here
Index:
Smart Coffee Software Features
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:
4/6 wire Load Cell Input
I2C display screen interface
2x Pressure transducer inputs
2x Boiler water level detection probes
Brew Switch input
Espresso mode selection input
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
Ultrasonic distance sensor (for measuring water level inside a reservoir tank)
2x MAX31865 temperature sensors (compatible with 2, 3, and 4 wire probes. PT100 and PT1000 series compatible)
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
7x 5VDC relay control outputs: (used to control external relays for high current loads)
2x Boiler element
1x Pump
4x Programable relays
Smart Coffee Software Features:
Single and Dual boiler compatible with a single group head
PID and PWM logic boiler control
Boiler target can be programmed as Temperature or Pressure
Boiler water level probes (used to trigger a refill when required)
Display metric units (kPa, Celsius, grams, mls) or imperial units (PSI, Fahrenheit, Ounces, fluid ounces)
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)
Momentary or latching switch compatible for Brew and Espresso mode switches
Pressure transducer inputs to control/monitor pressure
Programmable pressure safety limits (machines shuts down when safety limits are exceeded)
Thermocouple temperature sensors to monitor any temperature on the machine
Programmable pressure safety limits (machines shuts down when safety limits are exceeded)
Espresso shot output (when espresso mode is activated by the user)
Espresso shot timer
Espresso shot by weight target (requires loadcell)
Espresso shot by volume target (requires flow meter)
Pause boiler refill (pauses a boiler refill if an espresso extraction is currently taking place)
Ultrasonic distance sensor (used for machines with a reservoir tank to measure the water level)
Reservoir empty standby mode (prevents the machine from operating until the reservoir is refilled)
Programming and wiring guides:
Download the programming guide: click here
Download the wiring guide: click here
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 send an email describing your software configuration, the sensors you are using, and the bug you have encountered to mail@schematix.co.nz
Updates for Smart Coffee:
Change log and updates:
V1.0 Base version published
PCB Dimensions:
Width: 101mm (3.97")
Length: 153mm (6.02")
Mounting hole spacing: 145mm (5.7") x 93mm (3.66")
Mounting hole size: 3.7mm
I am thinking of DIY an expresso machine, would like to understand more on your control board, The current design support two thermocouples for steam and brew boilers, what about adding the 3rd one for brew head ? On the pump control, I am considering using PWM control for gear or DC rotary pump. Can the board extended the PWM control for Pump in addition to control the heat element ?
I am designing an enclosure for this new board. what kind of air flow should I build in for it? should I add a provision for a cooling fan?
I am thinking about swapping my vibratory pump out with a fluid-o-tech gear motor. The one i have runs on a 24v DC stepper style motor. I figured I can have the motor relay switch on the power to a motor power supply, but what would be nice is the ability to adjust the motor RPMS via the control wire(you send it 0-5v )
Also why bother with connecting these via USB when the boards have wifi?
(it's a little bit messy I apologize) I would like to use the ultrasonic distance sensor to monitor both of these. The green is my water Reservoir that gets pumped into the coffee machine and beside it is the water waste. My thinking here is I could use what you've shared with the pogo connecters when I need to remove these as the cords would obviously be external. Sound doable?
Question for the presence sensor probably a lot more to come lol.. My Rocket Espresso Giotto Evoluzione R does 9 bar so should I get 1.2 MPa (1200 kPa) to be a more suitable option to handle the higher pressure and provide a safety margin?
Im currently using Smart Coffee with the Arduino Mega. I originally was trying to use the flow meters to control shot time, but the way my machine is plumbed, I would really need 3 meters to get a truly accurate reading, so I have switched to just a timer based setup which works ok. If I upgrade to this new board, I will definitely go with the scale function. I know the little screen does not have a lot of real-estate but what I would really like is to have the high pressure flow meter as well and be able to see the weight, dispensed water volume and a shot timer all on the screen.
Neat update! To upgrade from the original smart coffee, we would just need your custom board, 2 ESP32's, and additional sensors such as the load cell?