Integration examples
Home Assistant~
Use a LUA Script to publish the charger state, power, session energy, temperature, error states as MQTT topics, and accept commands to enable/disable charging and to set the charging current. Optionally announce everything to Home Assistant via MQTT autodiscovery so the entities appear automatically.
Set the values in the script directly overwriting the defaults or from the web UI: Scripting -> components -> "MQTT bridge to Home Assistant".
EVSE identifier is important in case of autodiscovery, as it is used as topic prefix, as node path to uniquely identify the charger and when generating entity ids.
File /usr/lua/ha_bridge.lua:
local evse = require("evse")
local energymeter = require("energymeter")
local mqtt = require("mqtt")
local json = require("json")
local STATE_NAMES = {
[evse.STATEA] = "A",
[evse.STATEB1] = "B1",
[evse.STATEB2] = "B2",
[evse.STATEC1] = "C1",
[evse.STATEC2] = "C2",
[evse.STATED1] = "D1",
[evse.STATED2] = "D2",
[evse.STATEE] = "E",
[evse.STATEF] = "F",
}
local function truthy(data)
data = tostring(data):lower()
return data == "on" or data == "1" or data == "true"
end
local function sanitize_identifier(value)
local s = tostring(value or ""):lower()
if not s:match("^[a-z0-9]+$") then
error("invalid EVSE identifier '" .. tostring(value) ..
"': use only a-z and 0-9 (no spaces, dashes, dots or other characters)")
end
return s
end
return {
id = "ha_bridge",
name = "MQTT bridge to Home Assistant",
description = "Home Assistant MQTT bridge with entity autodiscovery",
params = {
uri = { type = "string", name = "Broker URI", default = "mqtt://192.168.1.10:1883" },
username = { type = "string", name = "Username", default = "user" },
password = { type = "string", name = "Password", default = "pass" },
identifier = { type = "string", name = "EVSE identifier", default = "evse" },
interval = { type = "number", name = "Publish interval (s)", default = 5 },
discovery = { type = "boolean", name = "Publish HA discovery", default = true },
},
start = function(params)
print("starting Home Assistant bridge...")
local raw = params.identifier
if raw == nil or raw == "" then raw = "evse" end
local id = sanitize_identifier(raw)
local interval_ms = math.max(1, math.floor(params.interval or 10)) * 1000
local state_topic = id .. "/state"
local cmd_topic = id .. "/+/set"
-- empty credential fields -> nil (anonymous broker)
local user = (params.username ~= "") and params.username or nil
local pass = (params.password ~= "") and params.password or nil
local client = mqtt.client(params.uri, user, pass)
-- Home Assistant discovery: one device, all entities read the single
-- state topic through value_template. Config topics are retained.
local function announce()
local device = { identifiers = { id }, name = id, manufacturer = "esp32-evse", model = "esp32-evse" }
-- slug becomes the entity id suffix: <domain>.<id>_<slug>
local function disco(kind, slug, cfg)
cfg.object_id = id .. "_" .. slug -- HA derives entity_id from object_id
cfg.unique_id = id .. "_" .. slug
cfg.device = device
client:publish("homeassistant/" .. kind .. "/" .. id .. "/" .. slug .. "/config",
json.encode(cfg), 0, 1)
end
disco("sensor", "state", {
name = "State", state_topic = state_topic,
value_template = "{{ value_json.state }}", icon = "mdi:ev-station" })
disco("sensor", "power", {
name = "Power", state_topic = state_topic,
value_template = "{{ value_json.power }}",
unit_of_measurement = "W", device_class = "power", state_class = "measurement" })
disco("sensor", "session_energy", {
name = "Session energy", state_topic = state_topic,
value_template = "{{ value_json.session_energy }}",
unit_of_measurement = "Wh", device_class = "energy", state_class = "total_increasing" })
disco("sensor", "temperature", {
name = "Temperature", state_topic = state_topic,
value_template = "{{ value_json.temperature }}",
unit_of_measurement = "°C", device_class = "temperature", state_class = "measurement" })
disco("binary_sensor", "charging", {
name = "Charging", state_topic = state_topic,
value_template = "{{ 'ON' if value_json.charging else 'OFF' }}",
payload_on = "ON", payload_off = "OFF", device_class = "battery_charging" })
disco("binary_sensor", "error", {
name = "Error", state_topic = state_topic,
value_template = "{{ 'ON' if value_json.error else 'OFF' }}",
payload_on = "ON", payload_off = "OFF", device_class = "problem" })
disco("switch", "charging_enabled", {
name = "Charging enabled", state_topic = state_topic,
value_template = "{{ 'ON' if value_json.enabled else 'OFF' }}", icon = "mdi:ev-plug-type2",
command_topic = id .. "/enabled/set",
payload_on = "ON", payload_off = "OFF", state_on = "ON", state_off = "OFF" })
disco("number", "charging_current_limit", {
name = "Charging current limit", state_topic = state_topic,
value_template = "{{ value_json.current }}", icon = "mdi:current-ac",
command_topic = id .. "/current/set",
min = 6, max = evse.getmaxchargingcurrent(), step = "0.1",
unit_of_measurement = "A", mode = "slider" })
end
return coroutine.create(function()
repeat
print("connecting...")
until client:connect()
print("connected!")
if params.discovery then announce() end
-- one subscription with a wildcard; dispatch by the middle segment
client:subscribe(cmd_topic, function(topic, data)
-- topic is "<id>/<what>/set" -> extract <what>
local what = string.sub(topic, #id + 2)
what = string.sub(what, 1, #what - 4) -- strip "/set"
local methods = {
enabled = function() evse.setenabled(truthy(data)) end,
current = function()
local amps = tonumber(data)
if amps then
-- setchargingcurrent raises on out-of-range values
if not pcall(evse.setchargingcurrent, amps) then
print("ha_bridge: rejected current '" .. tostring(data) .. "'")
end
end
end,
}
if methods[what] then methods[what]() end
end)
while true do
local state = evse.getstate()
local payload = {}
payload.state = STATE_NAMES[state] or "?"
payload.charging = state == evse.STATEC2 or state == evse.STATED2
payload.enabled = evse.getenabled()
payload.error = evse.geterror() > 0
payload.power = energymeter.getpower()
payload.current = evse.getchargingcurrent()
payload.session_energy = energymeter.getconsumption()
payload.temperature = evse.gethightemperature()
client:publish(state_topic, json.encode(payload), 0, 1) -- retained
coroutine.yield(interval_ms)
end
end)
end
}
Note
Don't forget to add component.register(require("ha_bridge")) to your /usr/lua/init.lua file.
ThingsBoard cloud MQTT~
Implementing an integration to ThingsBoard cloud with a LUA Script:
File /usr/lua/thingsboard.lua:
local evse = require("evse")
local energymeter = require("energymeter")
local mqtt = require("mqtt")
local json = require("json")
return {
id = "thingsboard",
name = "ThingsBooard",
description = "ThingsBooard MQTT connector",
params = {
token = { type = "string", name = "Access token" }
},
start = function(params)
print("starting thingsboard connector...")
if not params.token then
error("require access token")
end
local client = mqtt.client("mqtt://demo.thingsboard.io:1883", params.token)
return coroutine.create(function()
repeat
print("connecting...")
until client:connect()
print("conected!")
client:subscribe("v1/devices/me/rpc/request/+", function(topic, data)
local payload = json.decode(data)
local reqid = string.sub(topic, #"v1/devices/me/rpc/request/" + 1)
local restopic = "v1/devices/me/rpc/response/" .. reqid
function response(value)
client:publish(restopic, json.encode({ value = value }))
end
local methods = {
["getEnabled"] = function()
response(evse.getenabled())
end,
["setEnabled"] = function(param)
evse.setenabled(param)
end,
["getChargingCurrent"] = function()
response(evse.getchargingcurrent())
end,
["setChargingCurrent"] = function(param)
evse.setchargingcurrent(param)
end
}
if methods[payload.method] ~= nil then
methods[payload.method](payload.params)
end
end)
while true do
local payload = {}
local state = evse.getstate()
payload["session"] = state >= evse.STATEB1 and state <= evse.STATED2
payload["charging"] = state == evse.STATEC2 or state == evse.STATED2
payload["enabled"] = evse.getenabled()
payload["available"] = evse.getavailable()
payload["error"] = evse.geterror() > 0
payload["consumption"] = energymeter.getconsumption()
payload["power"] = energymeter.getpower()
payload["temperature"] = evse.gethightemperature()
payload["uptime"] = os.clock()
payload["currentL1"], payload["currentL2"], payload["currentL3"] = energymeter.getcurrent()
payload["voltageL1"], payload["voltageL3"], payload["voltageL3"] = energymeter.getvoltage()
client:publish("v1/devices/me/telemetry", json.encode(payload))
coroutine.yield(60000)
end
end)
end
}
Note
Don't forget to add component.register(require("thingsboard")) to your /usr/lua/init.lua file.
EVCC~
Here's a mapping between REST API and EVCC. Replace EVSE_IP with your charger's address:
chargers:
- name: esp32evse
type: custom # continuous current control + built-in meter
# status: map ESP32-EVSE state (A,B1,B2,C1,C2,D1,D2,E,F) to EVCC's A..F
status:
source: http
uri: http://EVSE_IP/api/v1/state
jq: .state[0:1] # first letter only: B1/B2->B, C1/C2->C, D1/D2->D
enabled: # is charging enabled? -> bool
source: http
uri: http://EVSE_IP/api/v1/state
jq: .enabled
enable: # start/stop charging
source: http
uri: http://EVSE_IP/api/v1/state/enabled
method: POST
headers:
- content-type: application/json # required, else the firmware returns 415
body: "{{if .enable}}true{{else}}false{{end}}"
maxcurrent: # integer A
source: http
uri: http://EVSE_IP/api/v1/state/charging-current
method: POST
headers:
- content-type: application/json
body: "{{.maxcurrent}}"
maxcurrentmillis: # fractional A -> "dimmable"; device rounds to 0.1 A
source: http
uri: http://EVSE_IP/api/v1/state/charging-current
method: POST
headers:
- content-type: application/json
body: "{{.maxcurrentmillis}}"
# ---- built-in meter ----
power:
source: http
uri: http://EVSE_IP/api/v1/state
jq: .power # W
energy:
source: http
uri: http://EVSE_IP/api/v1/state
jq: .totalConsumption / 3600000 # Ws -> kWh (lifetime, monotonic)
currents: # must be exactly three entries
- { source: http, uri: "http://EVSE_IP/api/v1/state", jq: .current[0] }
- { source: http, uri: "http://EVSE_IP/api/v1/state", jq: .current[1] }
- { source: http, uri: "http://EVSE_IP/api/v1/state", jq: .current[2] }
voltages:
- { source: http, uri: "http://EVSE_IP/api/v1/state", jq: .voltage[0] }
- { source: http, uri: "http://EVSE_IP/api/v1/state", jq: .voltage[1] }
- { source: http, uri: "http://EVSE_IP/api/v1/state", jq: .voltage[2] }
loadpoints:
- title: Garage
charger: esp32evse
mode: pv
mincurrent: 6
maxcurrent: 16 # <= the device's maxChargingCurrent
phases: 1 # set to your wiring (1 or 3)
Note
This hasn't been thoroughly tested. Please give feedback if you try it.
Note
ESP32-EVSE stores charging current at 0.1 A (deci-amp) granularity, so the "milliamp" path really gives 100 mA steps. It's genuinely continuously dimmable, just not to 1 mA.
Energy uses totalConsumption, not consumption. EVCC treats the charger's energy as a monotonic counter and diffs
it for session energy; consumption resets to 0 each session and would produce negative diffs, so use the lifetime counter.
Set ESP32-EVSE so it doesn't require authorization for charging. If HTTP Basic credentials are set, add an auth: block (type: basic, user:, password:) to each plugin.
ESPHome~
The AT commands engine can be used to communicate from other open source projects like ESPHome with ESP32-EVSE.
This external ESPHome component implements accessing most EVSE parameters as ESPHome sensors, binary sensors, text sensors, switches, buttons, number inputs. These can appear in ESPHome and Home Assistant as native components.
It is intended to be used on a separate ESP32 microcontroller connected to ESP32-EVSE thorugh an UART. The biggest advantage here is that ESP32-EVSE doesn't have to deal with any of the above, can keep working independently as a mission critical piece of hardware, all this functionality can run separately without generating extra load on the charger.
The Things Network (LoRaWAN)~
Communication over LoRaWAN network, using a Dragino RS485-LN (ModBUS to LoRaWAN Converter).
Set RS-485 serial interface type for ModBUS mode, and default parameters for Dragino are: baud rate: 9600, data bits: 8, stop bits: 1, parity: disable.
Dragino configuration
Serial port parameters: AT+BAUDR, AT+PARITY, AT+DATABIT, AT+STOPBIT commands.
AT+TDC=60000
AT+DECRYPT=0
AT+MBFUN=0
AT+BAUDR=9600
AT+PARITY=0
AT+DATABIT=8
AT+STOPBIT=0
AT+DATAUP=0
AT+PAYVER=1
AT+CHS=0
AT+RXMODE=0,0
AT+COMMAND1=01 03 00 64 00 04, 1
AT+DATACUT1=13,2,4~9+11~11
AT+CMDDL1=0
AT+COMMAND2=01 03 00 c8 00 03, 1
AT+DATACUT2=11,2,4~9
AT+CMDDL2=0
AT+COMMAND3=01 03 00 cf 00 0c, 1
AT+DATACUT3=29,2,4~27
AT+CMDDL3=0
AT+COMMAND4=01 03 01 90 00 04, 1
AT+DATACUT4=13,2,4~7+10~11
AT+CMDDL4=0
The Things Network
After sucesffuly adding Dragino to your app, set JavaScript payload decoder:
function decodeUplink(input) {
function uint32(idx) {
return input.bytes[idx] << 24 | input.bytes[idx + 1] << 16 | input.bytes[idx + 2] << 8 | input.bytes[idx + 3];
}
function uint16(idx) {
return input.bytes[idx] << 8 | input.bytes[idx + 1];
}
function toSint16(value) {
if ((value & 1 << 15) > 0) { // value is negative (16bit 2's complement)
value = ((~value) & 0xffff) + 1; // invert 16bits & add 1 => now positive value
value = value * -1;
}
return value;
}
return {
data: {
state: String.fromCharCode(input.bytes[1]) + (input.bytes[2] > 0 ? String.fromCharCode(input.bytes[2]) : ''),
errors: uint32(3),
enabled: input.bytes[7] === 1,
power: uint16(8),
consumption: uint32(10),
voltage: [
uint32(14) / 1000,
uint32(18) / 1000,
uint32(22) / 1000,
],
current: [
uint32(26) / 1000,
uint32(30) / 1000,
uint32(34) / 1000,
],
uptime: uint32(38),
temperature: toSint16(uint16(42)) / 100,
},
warnings: [],
errors: []
};
}
After setup, you should see live data in TTN console:
