Setting up device¶

The device can operate in two modes and must be in configuration mode in order for the web server to be active.

One of the following conditions will place the device in configuration mode:

Gyro has not been calibrated
Sleep mode has been disabled in the web interface
Placed in horizontal mode 85-90 degrees
Charger connected >4.15V

Status¶

Configuration is accessed by entering the URL for the device, this will be the mDNS name device.local or the IP adress. The following chapter assumes the device name is gravmon.

The main page shows the device readings; gravity, angle, temperature and battery charge. If the checkbox is active then the device will never go into sleep mode. This is useful if you are collecting angle/tilt for calibration. If this is unchecked the device will change mode as explained before.

Tip

If you are connected to the device via a serial console (speed: 115200) you can see the connection sequence and get the Unique ID and IP adress from there.

Device¶

URL: (http://gravmon.local/device)

Version:

Installed version of the code and html files.
Device name:

This is unique name of the device.
Device ID:

This is unique identifier for the device (ESP8266 id), this is required when using the API as an API Key to safeguard against faulty requests.

Configuration¶

URL: (http://gravmon.local/config)

Device Setting¶

Device name:

This is unique name for the device. It will be used in pushing data as well as mDNS name on the network (<name>.local)
Temperature format:

Choose between Celsius and Farenheight
Interval:

This defines how long the device should be sleeping between the readings when in gravity monitoring mode. You will also see the values in minutes/seconds to easier set the interval. 900s is a recommended interval.

Note

The sleep interval can be set between 10 - 3600 seconds (60 minutes).

Calibration values:

These are calibration data for the gyro. Place the device flat on a table and press the button to save the default orientation values. Without this calibration we cannot calculate the correct angle/tilt.

Warning

The device will not go into gravity monitoring mode unless calibrated

Push Settings¶

Note

When enabling SSL this will not validate the root CA of the remote service, this is a design decision based on two aspects. Enabling CA validation will take 3-4s extra on each connection which means way less battery life, so the decision is to prioritize battery life over security. The data transmitted is not really that sensitive anyway so I belive this is a good balance.

HTTP URL 1:

Endpoint to send data via http. Default format used Format used iSpindle format. You can customize the format using Format editor.

If you add the prefix https:// then the device will use SSL when sending data.
HTTP URL 2:

Endpoint to send data via http. Default format used iSpindle format. You can customize the format using Format editor.

If you add the prefix https:// then the device will use SSL when sending data.
Brewfather URL:

Endpoint to send data via http to brewfather. Format used Brewfather format

SSL is not supported for this target.
Influx DB v2 URL:

Endpoint to send data via http to InfluxDB. Format used Influx DB v2. You can customize the format using Format editor.

SSL is not supported for this target. Raise a issue on github if this is wanted.
Influx DB v2 Organisation:

Name of organisation in Influx.
Influx DB v2 Bucket:

Identifier for bucket.
Influx DB v2 Token:

Token with write access to bucket.
MQTT server:

IP or name of server to send data to. Default format used MQTT. You can customize the format using Format editor.
MQTT Port:

Which port should be used for communication, default is 1883 (standard port). For SSL use 8883 (any port over 8000 is treated as SSL).
MQTT user:

Username or blank if anonymous is accepted
MQTT password:

Password or blank if anonymous is accepted

Gravity Settings¶

Gravity format:

Gravity format can be eihter SG or Plato. The device will use SG Internally and convert to Plato when displaying data.
Gravity formula:

Gravity formula is compatible with standard iSpindle formulas so any existing calculation option can be used. You can also use the feature to create the formula by supplying the raw data. See Create formula
Temperature correct gravity:

Will apply a temperature calibration formula to the gravity as a second step.

Warning

This formula assumes that the calibration has been done at 20°C / 68°F.

Formula used in temperature correction.

gravity*((1.00130346-0.000134722124*temp+0.00000204052596*temp^2-0.00000000232820948*temp^3)/
(1.00130346-0.000134722124*cal+0.00000204052596*cal^2-0.00000000232820948*cal^3))

Hardware Settings¶

Voltage factor:

Factor used to calcualate the battery voltage. If you get a too low/high voltage you can adjust this value.
Temperature correction:

This value will be added to the temperature reading (negative value will reduce temperature reading). This is applied when the device starts. So changing this will not take affect until the device is restarted.
Gyro Temperature:

Enable this feature will use the temp sensor i the gyro instead of the DS18B20, the benefit is shorter run time and longer battery life (this is an experimental feature). The value used is the first temperature reading from when the device is activated, since the gyro should be cool this is reflecting the surronding temperature. After it has been running the value would be totally off.
OTA URL:

Should point to a URL where the .bin file + version.json file is located.

For the OTA to work, place the following files (version.json + firmware.bin) at the location that you pointed out in OTA URL. If the version number in the json file is newer than in the code the update will be done during startup.

If you have the previx https:// then the device will use secure transfer without CA validation.

Example; OTA URL (don’t forget trailing dash), the name of the file should be firmware.bin

http://192.168.1.1/firmware/gravmon/

Format editor¶

To reduce the need for adding custom endpoints for various services there is an built in format editor that allows the user to customize the format being sent to the push target.

Warning

Since the format templates can be big this function can be quite slow on a small device such as the esp8266.

You enter the format data in the text field and the test button will show an example on what the output would look like. If the data cannot be formatted in json it will just be displayed as a long string. The save button will save the current formla and reload the data from the device.

Tip

If you save a blank string the default template will be loaded.

These are the format keys available for use in the format.

Directory structure¶
key	description	example
${mdns}	Name of the device	gravmon2
${id}	Unique id of the device	e422a3
${sleep-interval}	Seconds between data is pushed	900
${temp}	Temperature in format configured on device, one decimal	21.2
${temp-c}	Temperature in C, one decimal	21.2
${temp-f}	Temperature in F, one decimal	58.0
${temp-unit}	Temperature format C or F	C
${battery}	Battery voltage, two decimals	3.89
${rssi}	Wifi signal strength	-75
${run-time}	How long the last measurement took, two decimals	3.87
${angle}	Angle of the gyro, two decimals	28.67
${tilt}	Same as angle.	28.67
${gravity}	Calculated gravity, 4 decimals for SG and 1 for Plato.	1.0456
${gravity-sg}	Calculated gravity in SG, 4 decimals	1.0456
${gravity-plato}	Calculated gravity in Plato, 1 decimal	8.5
${corr-gravity}	Temperature corrected gravity, 4 decimals for SG and 1 for Plato.	1.0456
${corr-gravity-sg}	Temperature corrected gravity in SG, 4 decimals	1.0456
${corr-gravity-plato}	Temperature corrected gravity in Plato, 1 decimal	8.5
${gravity-unit}	Gravity format, G or P	G

Create formula¶

Here you can enter up to 5 values (angles + gravity) that is then used to create the formula. Angles equal to zero will be regarded as empty even if there is a gravity reading.

Once the formula is created a graph over the entered values and a simulation of the formula will give you a nice overview on how the formula will work.

REST API¶

All the API’s use a key called ID which is the unique device id (chip id). This is used as an API key when sending requests to the device.

GET: /api/config¶

Retrive the current configuation of the device via an HTTP GET command. Payload is in JSON format.

temp-format can be either C or F
gravity-format is always G (plato is not yet supported)

Other parameters are the same as in the configuration guide.

{
   "mdns": "gravmon",
   "id": "ee1bfc",
   "ota-url": "http://192.168.1.50:80/firmware/gravmon/",
   "temp-format": "C",
   "brewfather-push": "http://log.brewfather.net/stream?id=Qwerty",
   "http-push": "http://192.168.1.50:9090/api/v1/Qwerty/telemetry",
   "http-push2": "http://192.168.1.50/ispindel",
   "influxdb2-push": "http://192.168.1.50:8086",
   "influxdb2-org": "Qwerty",
   "influxdb2-bucket": "Qwerty",
   "influxdb2-auth": "Qwerty",
   "mqtt-push": "192.168.1.50",
   "mqtt-port": 1883,
   "mqtt-user": "Qwerty",
   "mqtt-pass": "Qwerty",
   "sleep-interval": 30,
   "voltage-factor": 1.59,
   "gravity-formula": "0.0*tilt^3+0.0*tilt^2+0.0017978*tilt+0.9436",
   "gravity-format": "G",
   "temp-adjustment-value": 0,
   "gravity-temp-adjustment": false,
   "gyro-temp": true,
   "gyro-calibration-data": {
      "ax": -330,
      "ay": -2249,
      "az": 1170,
      "gx": 99,
      "gy": -6,
      "gz": 4
   },
   "angle": 90.93,
   "gravity": 1.105,
   "battery": 0.04
}

GET: /api/device¶

Retrive the current device settings via an HTTP GET command. Payload is in JSON format.

{
   "app-name": "GravityMon ",
   "app-ver": "0.0.0",
   "id": "ee1bfc",
   "mdns": "gravmon"
}

GET: /api/status¶

Retrive the current device status via an HTTP GET command. Payload is in JSON format.

temp-format can be either C or F

Other parameters are the same as in the configuration guide.

{
   "id": "ee1bfc",
   "angle": 89.86,
   "gravity": 1.1052,
   "gravity-tempcorr": 1.1031,
   "temp-c": 0,
   "temp-f": 32,
   "battery": 0,
   "temp-format": "C",
   "sleep-mode": false,
   "rssi": -56
}

GET: /api/config/formula¶

Retrive the data used for formula calculation data via an HTTP GET command. Payload is in JSON format.

a1-a4 are the angles/tilt readings (up to 5 are currently supported)
g1-g4 are the corresponding gravity reaadings in SG or Plato depending on the device-format.

{
   "id": "ee1bfc",
   "a1": 22.4,
   "a2": 54.4,
   "a3": 58,
   "a4": 0,
   "a5": 0,
   "g1": 1.000,
   "g2": 1.053,
   "g3": 1.062,
   "g4": 1,
   "g5": 1,
   "gravity-format": "G",
   "gravity-formula": "0.0*tilt^3+0.0*tilt^2+0.0017978*tilt+0.9436"
}

POST: /api/config/device¶

Used to update device settings via an HTTP POST command. Payload is in JSON format.

temp-format can be either C (Celcius) or F (Farenheight)

{
   "id": "ee1bfc",
   "mdns": "gravmon",
   "temp-format": "C",
   "sleep-interval": 30
}

POST: /api/config/push¶

Used to update push settings via an HTTP POST command. Payload is in JSON format.

{
   "id": "ee1bfc",
   "http-push": "http://192.168.1.50/ispindel",
   "http-push2": "",
   "brewfather-push": "",
   "influxdb2-push": "http://192.168.1.50:8086",
   "influxdb2-org": "Qwerty",
   "influxdb2-bucket": "Qwerty",
   "influxdb2-auth": "Qwerty"
   "mqtt-push": "192.168.1.50",
   "mqtt-port": 1883,
   "mqtt-user": "Qwerty",
   "mqtt-pass": "Qwerty",
}

POST: /api/config/gravity¶

Used to update gravity settings via an HTTP POST command. Payload is in JSON format.

gravity-formula keywords temp and tilt are supported.
gravity-format can be either G (SG) or P (PLATO)

Note

gravity-temp-adjustment is defined as “on” or “off” when posting since this is the output values from a checkbox, when reading data it’s sent as boolean (true,false).

{
   "id": "ee1bfc",
   "gravity-formula": "0.0*tilt^3+0.0*tilt^2+0.0017978*tilt+0.9436",
   "gravity-format": "P",
   "gravity-temp-adjustment": "off"
}

POST: /api/config/hardware¶

Used to update hardware settings via an HTTP POST command. Payload is in JSON format.

Note

gyro-temp is defined as “on” or “off” when posting since this is the output values from a checkbox, when reading data it’s sent as boolean (true,false).

{
   "id": "ee1bfc",
   "voltage-factor": 1.59,
   "temp-adjustment": 0,
   "gyro-temp": "off",
   "ota-url": "http://192.168.1.50/firmware/gravmon/"
}

POST: /api/config/formula¶

Used to update formula calculation data via an HTTP POST command. Payload is in JSON format.

a1-a4 are the angles/tilt readings (up to 5 are currently supported)
g1-g4 are the corresponding gravity reaadings (in SG)

{
   "id": "ee1bfc",
   "a1": 22.4,
   "a2": 54.4,
   "a3": 58,
   "a4": 0,
   "a5": 0,
   "g1": 1.000,
   "g2": 1.053,
   "g3": 1.062,
   "g4": 1,
   "g5": 1
}

Calling the API’s from Python¶

Here is some example code for how to access the API’s from a python script. Keys should always be present or the API call will fail.

import requests
import json

host = "192.168.1.1"           # IP adress (or name) of the device to send these settings to
id = "ee1bfc"                  # Device ID (shown in serial console during startup or in UI)

def set_config( url, json ):
   headers = { "ContentType": "application/json" }
   print( url )
   resp = requests.post( url, headers=headers, data=json )
   if resp.status_code != 200 :
      print ( "Failed "  )
   else :
      print ( "Success "  )

url = "http://" + host + "/api/config/device"
json = { "id": id,
         "mdns": "gravmon",             # Name of the device
         "temp-format": "C",            # Temperature format C or F
         "sleep-interval": 30           # Sleep interval in seconds
      }
set_config( url, json )

url = "http://" + host + "/api/config/push"
json = { "id": id,
         "http-push": "http://192.168.1.1/ispindel",
         "http-push2": "",
         "brewfather-push": "",
         "influxdb2-push": "",
         "influxdb2-org": "",
         "influxdb2-bucket": "",
         "influxdb2-auth": "",
         "mqtt-push": "192.168.1.50",
         "mqtt-port": 1883,
         "mqtt-user": "Qwerty",
         "mqtt-pass": "Qwerty"
         }
set_config( url, json )

url = "http://" + host + "/api/config/gravity"
json = { "id": id,
         "gravity-formula": "",
         "gravity-format": "P",
         "gravity-temp-adjustment": "off"        # Adjust gravity (on/off)
         }
set_config( url, json )

url = "http://" + host + "/api/config/hardware"
json = { "id": id,
         "voltage-factor": 1.59,                 # Default value for voltage calculation
         "temp-adjustment": 0,                   # If temp sensor needs to be corrected
         "gyro-temp": "on",                      # Use the temp sensor in the gyro instead (on/off)
         "ota-url": ""                           # if the device should seach for a new update when active
      }
set_config( url, json )

url = "http://" + host + "/api/formula"
json = { "id": id,
         "a1": 22.4,
         "a2": 54.4,
         "a3": 58,
         "a4": 0,
         "a5": 0,
         "g1": 1.000,
         "g2": 1.053,
         "g3": 1.062,
         "g4": 1,
         "g5": 1
         }
set_config( url, json )

Data Formats¶

iSpindle format¶

This is the format used for standard http posts.

corr-gravity is an extended parameter containing a temperature corrected gravity reading.
gravity-format is an extended parameter containing the gravity format (G or P).
run-time is an extended parameter containing the number of seconds the execution took.

{
   "name" : "gravmon",
   "ID": "2E6753",
   "token" : "gravmon",
   "interval": 900,
   "temperature": 20.5,
   "temp-units": "C",
   "gravity": 1.0050,
   "angle": 45.34,
   "battery": 3.67,
   "rssi": -12,

   "corr-gravity": 1.0050,
   "gravity-unit": "G",
   "run-time": 6
}

This is the format template used to create the json above.

{
 "name" : "gravmon", "
 "ID": "${id}", "
 "token" : "gravmon", "
 "interval": ${sleep-interval}, "
 "temperature": ${temp}, "
 "temp-units": "${temp-unit}", "
 "gravity": ${gravity}, "
 "angle": ${angle}, "
 "battery": ${battery}, "
 "rssi": ${rssi}, "
 "corr-gravity": ${corr-gravity}, "
 "gravity-unit": "${gravity-unit}", "
 "run-time": ${run-time} "
}

Brewfather format¶

This is the format for Brewfather. See: Brewfather API docs

{
   "name" : "gravmon",
   "temp": 20.5,
   "temp_unit": "C",
   "battery": 3.67,
   "gravity": 1.0050,
   "gravity_unit": "G",
}

Influx DB v2¶

This is the format for InfluxDB v2

measurement,host=<mdns>,device=<id>,temp-format=<C|F>,gravity-format=SG,gravity=1.0004,corr-gravity=1.0004,angle=45.45,temp=20.1,battery=3.96,rssi=-18

This is the format template used to create the json above.

measurement,host=${mdns},device=${id},temp-format=${temp-unit},gravity-format=${gravity-unit} gravity=${gravity},corr-gravity=${corr-gravity},angle=${angle},temp=${temp},battery=${battery},rssi=${rssi}

MQTT¶

This is the format used to send data to MQTT. Each of the lines are specific topics

ispindel/device_name/tilt 89.96796
ispindel/device_name/temperature 21.375
ispindel/device_name/temp_units C
ispindel/device_name/battery 0.04171
ispindel/device_name/gravity 33.54894
ispindel/device_name/interval 1
ispindel/device_name/RSSI -58

This is the format template used to create the json above.

Tip

Each line in the format is treated as one topic. The | is used as separator between lines and the first : is used as separator between topic and value. Each line is formatted as <topic>:<value>

ispindel/${mdns}/tilt:${angle}|
ispindel/${mdns}/temperature:${temp}|
ispindel/${mdns}/temp_units:${temp-unit}|
ispindel/${mdns}/battery:${battery}|
ispindel/${mdns}/gravity:${gravity}|
ispindel/${mdns}/interval:${sleep-interval}|
ispindel/${mdns}/RSSI:${rssi}|

This is a format template that is compatible with v0.6. Just replace the topic with the topic you want to post data to.

topic:{"name":"gravmon","ID":"${id}","token":"gravmon","interval": ${sleep-interval},"temperature": ${temp},"temp-units": "${temp-unit}","gravity":${gravity},"angle": ${angle},"battery":${battery},"rssi": ${rssi},"corr-gravity":${corr-gravity},"gravity-unit": "${gravity-unit}","run-time": ${run-time}}|

version.json¶

Contents version.json. The version is used by the device to check if the this version is newer. The html files will also be downloaded if the are present on the server. This way it’s easy to upgrade to a version that serve the html files from the file system. If they dont exist nothing will happen, the OTA flashing will still work. If the html files are missing from the file system they can be uploaded manually afterwards.

{
   "project":"gravmon",
   "version":"0.7.0",
   "html": [
      "index.min.htm",
      "device.min.htm",
      "config.min.htm",
      "format.min.htm",
      "calibration.min.htm",
      "about.min.htm"
   ]
}