Hi, I am posting a custom SNMP integration example here so that others might find it. I was trying to write an SNMP integration with OID string transformation and had to cobble together a configuration I found from several different forum posts (all were very helpful, thanks).
My requirement is pretty simple: I want to monitor the status of an ancient Datum Tymserve 2100 that I have running as an NTP server. There are three LEDs on the front panel of the device that correspond to three SNMP OIDs that need to be polled. I also want to transform the string returned by the device for each OID into custom text, with a custom icon depending on the value of the OID string.
There may be a better way to do this with platform templates, but this example works for me and I actually like having the original sensor (sensor.datum_tymserve_2100_foo) and transformed sensor (sensor.template_datum_tymserve_2100_foo) available.
My configuration.yaml:
sensor:
- platform: snmp
name: "Datum Tymserve 2100 tymingStatus"
# DESCRIPTION "This variable reflects the current status information on the 2100 Time and Frequency Processor."
# Tracking or Flywheeling
host: 192.168.0.19
# version: 1
community: public
baseoid: 1.3.6.1.4.1.601.1.1.2.1.2.2.0
accept_errors: true
scan_interval: 15
- platform: snmp
name: "Datum Tymserve 2100 tymingMode"
# DESCRIPTION "Operating mode of the timing engine."
# timecode (1)
# freerun (2)
# internal (3)
# gps (7)
host: 192.168.0.19
# version: 1
community: public
baseoid: 1.3.6.1.4.1.601.1.1.2.1.2.3.0
accept_errors: true
scan_interval: 15
- platform: snmp
name: "Datum Tymserve 2100 gpsAllinView"
# DESCRIPTION "Satellites in view packet from GPS."
# Example: Auto 3-D Sats: 3 28 27 16 9 26 31
host: 192.168.0.19
# version: 1
community: public
baseoid: 1.3.6.1.4.1.601.1.1.2.1.3.5.0
accept_errors: true
scan_interval: 60
template:
- sensor:
- name: template_datum_tymserve_2100_tymingstatus
state: >
{% if is_state("sensor.datum_tymserve_2100_tymingstatus", "Tracking") %}
Tracking
{% elif is_state("sensor.datum_tymserve_2100_tymingstatus", "Flywheeling") %}
Flywheeling
{% else %}
Error
{% endif %}
icon: >
{% if is_state("sensor.datum_tymserve_2100_tymingstatus", "Tracking") %}
mdi:satellite-variant
{% else %}
mdi:alert-circle
{% endif %}
- sensor:
- name: template_datum_tymserve_2100_tymingmode
state: >
{% set states = states("sensor.datum_tymserve_2100_tymingmode") | int %}
{% set text = {
1: "Timecode",
2: "Freerun",
3: "Internal",
7: "GPS"} %}
{{ text[states] if states in text.keys() else "Error" }}
icon: >
{% if is_state("sensor.datum_tymserve_2100_tymingmode", "7") %}
mdi:satellite-variant
{% else %}
mdi:alert-circle
{% endif %}
- sensor:
- name: template_datum_tymserve_2100_gpsallinview
state: >
{% set original_state = states("sensor.datum_tymserve_2100_gpsallinview") %}
{{ original_state | replace("Auto 3-D Sats: ", "") }}
icon: mdi:satellite-variant
Then I added it to my dashboard like this:
- square: false
type: grid
cards:
- type: tile
entity: sensor.template_datum_tymserve_2100_tymingstatus
name: tymingStatus
icon: ''
color: green
show_entity_picture: true
hide_state: false
vertical: false
icon_tap_action:
action: more-info
features_position: bottom
- type: tile
entity: sensor.template_datum_tymserve_2100_tymingmode
name: tymingMode
icon: ''
color: green
show_entity_picture: true
hide_state: false
state_content: state
vertical: false
icon_tap_action:
action: more-info
features_position: bottom
- type: tile
entity: sensor.template_datum_tymserve_2100_gpsallinview
name: gpsAllinView
icon: ''
color: green
show_entity_picture: true
hide_state: false
state_content: state
vertical: false
icon_tap_action:
action: more-info
features_position: bottom
columns: 2
title: Tymserve 2100
Which looks like this:
Is HA also an NMS 
?