diff options
Diffstat (limited to 'mh-z19.lua')
| -rw-r--r-- | mh-z19.lua | 37 |
1 files changed, 19 insertions, 18 deletions
@@ -1,28 +1,29 @@ -local mhz19 = {} +local mh_z19 = {} -local c_read = string.char(0xff, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79) +mh_z19.c_query = string.char(0xff, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79) -mhz19.co2 = nil -mhz19.temp = nil -mhz19.tt = nil -mhz19.ss = nil -mhz19.uu = nil +mh_z19.co2 = nil +mh_z19.temp = nil +mh_z19.abc_count = nil +mh_z19.abc_ticks = nil -function mhz19.query() - return c_read +function checksum(b1, b2, b3, b4, b5, b6, b7) + return 0xff - ((b1 + b2 + b3 + b4 + b5 + b6 + b7) % 0x100) + 1 end -function mhz19.parse_frame(data) - local head, cmd, co2h, co2l, temp, tt, ss, uh, ul = struct.unpack("BBBBBBBBB", data) - if head ~= 0xff or cmd ~= 0x86 then +function mh_z19.parse_frame(data) + local start, cmd, co2h, co2l, temp, u1, abc_ticks, abc_count, cksum = struct.unpack("BBBBBBBBB", data) + if start ~= 0xff or cmd ~= 0x86 then return false end - mhz19.co2 = co2h * 256 + co2l - mhz19.temp = temp - 40 - mhz19.tt = tt - mhz19.ss = ss - mhz19.uu = uh * 256 + ul + if checksum(cmd, co2h, co2l, temp, u1, abc_ticks, abc_count) ~= cksum then + return false + end + mh_z19.co2 = co2h * 256 + co2l + mh_z19.temp = temp - 40 + mh_z19.abc_ticks = abc_ticks + mh_z19.abc_count = abc_count return true end -return mhz19 +return mh_z19 |