122 lines
3.8 KiB
Lua
122 lines
3.8 KiB
Lua
--------------------------------------------------------------------------------
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-- DS18B20 one wire module for NODEMCU
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-- by @voborsky, @devsaurus
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-- encoder module is needed only for debug output; lines can be removed if no
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-- debug output is needed and/or encoder module is missing
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--
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-- by default the module is for integer version, comment integer version and
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-- uncomment float version part for float version
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--------------------------------------------------------------------------------
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return({
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pin=3,
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sens={},
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temp={},
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conversion = function(self)
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local pin = self.pin
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for i,s in ipairs(self.sens) do
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if s.status == 0 then
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print("starting conversion:", encoder.toHex(s.addr), s.parasite == 1 and "parasite" or " ")
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ow.reset(pin)
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ow.select(pin, s.addr) -- select the sensor
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ow.write(pin, 0x44, 1) -- and start conversion
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s.status = 1
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if s.parasite == 1 then break end -- parasite sensor blocks bus during conversion
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end
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end
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tmr.create():alarm(750, tmr.ALARM_SINGLE, function() self:readout() end)
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end,
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readTemp = function(self, cb, lpin)
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if lpin then self.pin = lpin end
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local pin = self.pin
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self.cb = cb
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self.temp={}
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ow.setup(pin)
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self.sens={}
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ow.reset_search(pin)
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-- ow.target_search(pin,0x28)
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-- search the first device
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local addr = ow.search(pin)
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-- and loop through all devices
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while addr do
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-- search next device
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local crc=ow.crc8(string.sub(addr,1,7))
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if (crc==addr:byte(8)) and ((addr:byte(1)==0x10) or (addr:byte(1)==0x28)) then
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ow.reset(pin)
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ow.select(pin, addr) -- select the found sensor
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ow.write(pin, 0xB4, 1) -- Read Power Supply [B4h]
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local parasite = (ow.read(pin)==0 and 1 or 0)
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table.insert(self.sens,{addr=addr, parasite=parasite, status=0})
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print("contact: ", encoder.toHex(addr), parasite == 1 and "parasite" or " ")
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end
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addr = ow.search(pin)
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tmr.wdclr()
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end
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-- place powered sensors first
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table.sort(self.sens, function(a,b) return a.parasite<b.parasite end)
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node.task.post(node.task.MEDIUM_PRIORITY, function() self:conversion() end)
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end,
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readout=function(self)
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local pin = self.pin
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local next = false
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if not self.sens then return 0 end
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for i,s in ipairs(self.sens) do
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-- print(encoder.toHex(s.addr), s.status)
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if s.status == 1 then
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ow.reset(pin)
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ow.select(pin, s.addr) -- select the sensor
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ow.write(pin, 0xBE, 0) -- READ_SCRATCHPAD
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data = ow.read_bytes(pin, 9)
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local t=(data:byte(1)+data:byte(2)*256)
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if (t > 0x7fff) then t = t - 0x10000 end
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if (s.addr:byte(1) == 0x28) then
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t = t * 625 -- DS18B20, 4 fractional bits
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else
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t = t * 5000 -- DS18S20, 1 fractional bit
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end
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if 1/2 == 0 then
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-- integer version
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local sgn = t<0 and -1 or 1
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local tA = sgn*t
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local tH=tA/10000
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local tL=(tA%10000)/1000 + ((tA%1000)/100 >= 5 and 1 or 0)
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if tH and (tH~=85) then
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self.temp[s.addr]=(sgn<0 and "-" or "")..tH.."."..tL
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print(encoder.toHex(s.addr),(sgn<0 and "-" or "")..tH.."."..tL)
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s.status = 2
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end
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-- end integer version
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else
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-- float version
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if t and (math.floor(t/10000)~=85) then
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self.temp[s.addr]=t/10000
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print(encoder.toHex(s.addr), t)
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s.status = 2
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end
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-- end float version
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end
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end
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next = next or s.status == 0
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end
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if next then
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node.task.post(node.task.MEDIUM_PRIORITY, function() self:conversion() end)
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else
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self.sens = nil
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if self.cb then
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node.task.post(node.task.MEDIUM_PRIORITY, function() self.cb(self.temp) end)
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end
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end
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end
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})
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