Fan Timer

Had a need to turn on a fan after a period of the light being on then turn it off at some point after the light has been turned off. Came up with the following to do it and seems to work fine for me. Logic on the output unit wasn't an option. Add the mappings to the table in the below script and it should be good to go.

Resident 1 second script

Code:

-- Script runs each second (or whatever you want) and checks for stored values based on the timer_mappings table
-- Add an entry for each light and fan combination needing to be controlled


on_delay = 60                                                                -- Set the time period from light ON to fan ON
off_delay = 120                                                                -- Set the time period from light OFF to fan OFF

if not timer_mappings then                                                        -- set up light to fan mappings table
    timer_mappings = {
        {input = 'test_light', output = 'test_fan', status='idle'},
        {input = 'downstairs_bath_light', output = 'downstairs_bath_fan', status='idle'},
        {input = 'upstairs_toilet_light', output = 'upstairs_toilet_fan', status='idle'},
    }
end


for _, timer in ipairs(timer_mappings) do                                        -- Loop through each line in the table

    
    keyval = storage.get(timer.input, 0)                                        -- Get the stored value matching the input if it exists
    now = os.time()


    if (keyval > 0) then                                                        -- If the storage key exists (ie, greater than a value of zero)

        delta = now - keyval                                                    -- Calculate the difference between now and the stored value
        
        objLight = GetCBusByKW(timer.input, 'or')                                    -- Get the lighting object and extract the current state into light_state
        light_state = objLight[1].value

        objFan = GetCBusByKW(timer.input, 'or')
        local send_to_log = objFan[1].log                                        -- Get the groups 'log' flag

        
        if (delta >= on_delay and timer.status == 'idle') then                -- Turn on the fan if required
            if(light_state == 255) then                                            -- Check if the light is still on and if so, turn ON the fan
                SetCBusByKW({timer.output}, 'or', {target = 255, ramprate = 0})    -- Set the fan ON
                timer.status = 'fan_on'                                        -- Set OFF delay time
                storage.set(timer.input, os.time())                                -- Save current time and light keyword to storage
                
                if(send_to_log) then
                    log(string.format('FAN CONTROL: Turning Fan \'%s\' ON', timer.output))
                end
                
            else
                -- Set op back to idle if light if now OFF
                timer.op = 'idle'
                storage.delete(timer.input)
                
            end
            
        elseif (timer.status == 'fan_on' and light_state == 255) then                -- If light and fan are both ON
            storage.set(timer.input, os.time())                                    -- Keep resetting the current time for when light goes OFF
            
        elseif (delta >= off_delay and timer.status == 'fan_on' and light_state == 0) then
            SetCBusByKW({timer.output}, 'or', {target = 0, ramprate = 0})        -- Light off, timer expired, turn fan OFF
            storage.delete(timer.input)                                            -- Delete the storage variable
            timer.status = 'idle'                                                        -- Set timer op back to nothing
            
            if(send_to_log) then
                log(string.format('FAN CONTROL: Turning Fan \'%s\' OFF', timer.output))
            end
        else
        
        end
    
    elseif (keyval == 0 and timer.status ~= 'idle') then                                -- In case something messes up and gets out of sync
        timer.op = 'idle'
    else
    end
end

Lighting Group Event Script

Code:

value = event.getvalue()

-- DB Call to return object based on the raw id number
local objLight = db_GetObjectById(event.dstraw)

if (objLight == false) then
    log(string.format('FAN TIMER: Object \'%s\' was not found', event.dstraw))
else

    -- Pull out tagcache table
    local tagcache = split(objLight[1].tagcache, ',')
    local light_keyword = tagcache[1]

    -- Substitute the tags to get the fan keyword
    fan_keyword = string.gsub(light_keyword, "_light", "_fan")

    -- Get CBUS Level
    objFan = GetCBusByKW(fan_keyword, 'or')

    key = light_keyword

    -- If the light is switched on AND the fan is currently off, add to the storage variable
    if (value == 255 and objFan[1].value == 0) then
        log(string.format('FAN CONTROL: Light \'%s\' ON', light_keyword))
        storage.set(key, os.time())
    
    elseif (value == 0) then
        log(string.format('FAN CONTROL: Light \'%s\' OFF', light_keyword))

    end

end

And a couple of user library functions that didn't seem to already exist.

Code:

function db_GetObjectById(id)

    -- Return a table of object parameters based on the id
    local query = string.format('SELECT * FROM objects WHERE id = "%u"', id)
    liste = db:getall(query)

    if (table.maxn(liste) ~= 0) then
        return liste
    else
        return false
    end
    
end


function db_GetObjectTagById(id)

    -- Return a table of object parameters based on the id
    local query = string.format('SELECT * FROM objecttags WHERE object = "%u"', id)
    liste = db:getall(query)

    if (table.maxn(liste) ~= 0) then
        return liste
    else
        return false
    end
    
end

Only limitation of this is that the fan and lighting groups require that the first keyword aligns with the format of *_light and *.fan. Would be easy enough to add some logic to pull out a keyword with an identifier prefixed to enable it to be placed at any position but I really couldn't be bothered.