Quick OBS script in lua to write the local date/time to a text source.

local-datetime.lua

obs = obslua

module_description = "Sets a text source to act as a digital clock."

source_name = ""
date_format = "%c"

last_text = ""
last_timer = 30

function set_time_text()
  local text = os.date(date_format)

  if text ~= last_text then
    local source = obs.obs_get_source_by_name(source_name)
    if source ~= nil then
      if obs.obs_source_active(source) then
        local settings = obs.obs_data_create()
        obs.obs_data_set_string(settings, "text", text)
        obs.obs_source_update(source, settings)
        obs.obs_data_release(settings)
      end
      obs.obs_source_release(source)
    end
  end

  last_text = text
end

function script_load(settings)
  last_timer = obs.obs_data_get_int(settings, "timer")

  set_time_text()
  obs.timer_add(set_time_text, last_timer * 1000)
end

function script_update(settings)
  source_name = obs.obs_data_get_string(settings, "source")
  date_format = obs.obs_data_get_string(settings, "format")
  
  local timer = obs.obs_data_get_int(settings, "timer")
  if timer ~= last_timer then
    obs.timer_remove(set_time_text)
    obs.timer_add(set_time_text, timer * 1000)
    last_timer = timer
  end
end

function script_properties()
  local props = obs.obs_properties_create()
  
  local p = obs.obs_properties_add_list(props, "source", "Text Source", obs.OBS_COMBO_TYPE_EDITABLE, obs.OBS_COMBO_FORMAT_STRING)
  local sources = obs.obs_enum_sources()
  if sources ~= nil then
    for _, source in ipairs(sources) do
      source_id = obs.obs_source_get_unversioned_id(source)
      if source_id == "text_gdiplus" or source_id == "text_ft2_source" then
        local name = obs.obs_source_get_name(source)
        obs.obs_property_list_add_string(p, name, name)
      end
    end
  end
  obs.source_list_release(sources)

  obs.obs_properties_add_int_slider(props, "timer", "Update frequency", 1, 60, 1)

  local p = obs.obs_properties_add_text(props, "format", "Date format", obs.OBS_TEXT_DEFAULT)
  obs.obs_property_set_long_description(p, "Lua date format tags:\
  %a	abbreviated weekday name (e.g., Wed)  \
  %A	full weekday name (e.g., Wednesday)  \
  %b	abbreviated month name (e.g., Sep)  \
  %B	full month name (e.g., September)  \
  %c	date and time (e.g., 09/16/98 23:48:10)  \
  %d	day of the month [01-31]  \
  %H	hour, using a 24-hour clock [00-23]  \
  %I	hour, using a 12-hour clock [01-12]  \
  %M	minute [00-59]  \
  %m	month [01-12]  \
  %p	either `am` or `pm`  \
  %S	second [00-61]  \
  %w	weekday number [0-6 = Sunday-Saturday]  \
  %x	date (e.g., 09/16/98)  \
  %X	time (e.g., 23:48:10)  \
  %Y	full year  \
  %y	two-digit year [00-99]  \
  %%	the character `%´")

  return props
end

function script_defaults(settings)
  obs.obs_data_set_default_string(settings, "format", "%c")
  obs.obs_data_set_default_int(settings, "timer", 30)
end

function script_description()
  return module_description
end