#Gardener
A WIP demonstrating driving Atlas Scientific Industrial pH sensor and EC sensors through a single Arduino via Atlas's EZO pH circuit and EZO EC circuit.
Also controls a supply valve through which additional nutrient can be released into the garden, a pump through which spent nutrient can be evacuated, as well as a display that can indicate the status of the garden on-premisis.
In setup, the device onto which the firmware is loaded sits connected via USB to a Raspberry Pi, which is the gateway to the Internet. The Pi receives MQTT, WAMP/JSON-RPC, or other commands from an IoT service in the cloud, from which it then translates and messages to this device.
The hydroponic garden with which I used this software is described in the following diagram:
The Arduino is programmed to receive simple serial commands in the following language:
ECCALIL
Here, the first two characters represent the module (EC sensor, pH sensor, Valve, or Pump), and the next four characters represent a command to perform on that module, and the final character is a parameter, which some commands require and others do not. So, in this example, EC refers to the EC sensor module, CALI commands the EC sensor circuit to perform a calibration, and the L tells the EC sensor circuit that the type of calibration being performed is a calibration against low-conductivity test solution.
The full API is as follows:
| Module | Command | Param | Description |
|---|---|---|---|
| EC | READ | Read the value of the sensor | |
| EC | LEDS | 0 | Turn the LED on the EZO circuit off |
| EC | LEDS | 1 | Turn the LED on the EZO circuit on |
| EC | TYPE | 0 | Set the circuit to read from K=0.1 devices |
| EC | TYPE | 1 | Set the circuit to read from K=1.0 devices |
| EC | TYPE | 2 | Set the circuit to read from K=10.0 devices |
| EC | CALI | D | Perform a dry calibration |
| EC | CALI | L | Perform a calibration with low-conductivity calibration solution |
| EC | CALI | H | Perform a calibration with high-conductivity calibration colution |
| PH | READ | Read the value of the sensor | |
| PH | LEDS | 0 | Turn the LED on the EZO circuit off |
| PH | LEDS | 1 | Turn the LED on the EZO circuit on |
| PH | CALI | L | Perform a calibration with low-pH calibration solution |
| PH | CALI | M | Perform a calibration with mid-level-pH calibration solution |
| PH | CALI | H | Perform a calibration with high-pH calibration solution |
| PH | CALI | ? | Read the calibration status |
| PM | STRT | Start the drain pump | |
| PM | STOP | Stop the drain pump | |
| VL | OPEN | Open the supply valuve | |
| VL | CLOS | Close the supply valuve |
In addition to returning any values as appropriate, commands may return one of the following status codes:
| Status | Description |
|---|---|
| ERMODU | An invalid module has been supplied in the first two characters of the command |
| ERPARA | An invalid command or parameter has been supplied in the third through sixth or third through seventh characters of the command |
| ERCOMM | The gardener was not able to communicate with the specified device |
| OK | Worked |
 The Gardener |
 Inside the Gardener |
There is cruft in here, as it was a very quick pass to get the job done.
This work is licensed under a Creative Commons Attribution 4.0 International License.
