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Forum Index : Microcontroller and PC projects : Air Quality Sensors and Systems for MM?
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| Andrew_G Guru  Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Hi Phil (et al), My CCS811 arrived last week too but I couldn't play with it until yesterday. It worked straight out of the box - Geoff certainly is a Wizard! (such nice colours too) It is not yet 1/2 way through burning in. I have it in the same box as a SDS011. My plan is to isolate the two by poking a say 4mm thick gasket all around the CCS811 so that it only sees the outside air (otherwise it would also see dirty air from within the enclosure - including that sucked in by the SDS). (I too am seeing higher temperatures - my guess is that it is contributed to by the LCD and the other electronics in the box. I see this in my 6 other DS18B20s (with 1.8" LCDs). I reckon it is as much as 4+ degC with the 2.8" touch and about 2.5 for the 1.8"s). I now have all my DS18B20s poke outside the box but they are still compromised. One "test" I did was with a 1.8" LCD in a thermally stable room (bathroom with tiles and terrazzo all around). After I turned it on the temperature rose by 2.5 deg over 15-20 minutes then stabilised - I now can adjust the temperature readings at each station by sending an adjustment via HC-12.) Keep us posted. Cheers, Andrew |
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| zeitfest Guru Joined: 31/07/2019 Location: AustraliaPosts: 482 |
I don't want to be a killjoy here but.....be careful about burning wood that has been pressure-treated with preservative. In particular, a greenish preservative is often used to prevent munch by borer etc, namely copper arsenite, which will give you a nicely dispersed smoke containing serious amounts of arsenic. Not good for you at all.  |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Hi Zeitfest, Quite right about older treated pine but I think/hope that the newer stuff is less toxic (for that reason eg gets used in playgrounds etc)? But better not to burn any of it as softwood is no good any way (more smoke less heat etc and it clogs the flue). (I think it is Phil's neighbour that plans to burn it so it does get tricky.) Cheers, Andrew |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Not me that's planning on using the treated timber from the pallets. I am assuming that's what the neighbour is cutting them up for. Ours is a hundred year old weatherboard house that leaks some of the neighbouring smoke into certain rooms under particular conditions. Phil. |
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CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2076 |
ironic considering the thread  perhaps a test is in order? |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Stumbled across another sensor of interest just a while ago. Caught my eye as the name Sensirion is familiar to Davis Weather station users. Big thing that jumps out of the spec sheet is the life expectancy. >8 years with 24/7 operation. The 5 pin interface can be either UART or I²C with the Sel pin pulled low. RS's price is $84.00 (or a bit over $56 if you get a tray of 56). Might be an interesting on to play with down the track. 24/7 would be a bonus in the fire smoke monitoring situation mentioned above. I can just see myself smelling smoke & knowing I'm only getting 5 min readings as per Jim's previous suggestion. Re the lifespan of the SDS011, it gets a bit of a mention here. My SDS011 should turn up today, so will get the first taste of the readings. Phil. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Out of interest, this is Geoff's monitor after it spent the night in the bedroom again. The 12 hour mark corresponds to about 7:15pm & I called it quits a bit after 9:00. Was up about 2 hours before the graph ends.  Was up around the 1:00am mark & noticed an 1800ish reading & wonder if that's what disturbed me. Can't quite figure yet why the value rises so dramatically overnight. It's a 4x7m room with 3.2m ceiling. Renovated with new wall linings, paint & carpet about 10 years ago. All furnishings outdate that time frame. Cheers Phil. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
My SDS011 arrived today, So far have just run the Windows software that Andrew mentioned. Has anyone progressed further with their code? Was thinking of puting mine out in the inverter cabinet, where I already have an MM reading my energy meters. So would need to have it on Com2 & then incorporate the two sets of code. Maybe then way it up every 5 minutes @ times like 9:54:30 etc & take the readings @ 9:55:00 etc. Was thinking for testing an active LED would be helpful. Probably the simplest place to jump that would be across the fan pins. Other think I'd like to add is a HC-12 so my MM+ can poll it for data & log it. That would require a 3rd Com port, which could be done with the two CFunctions. but I don't think this could be interupt driven, which is what my polling from the "Coms Master" MM+ relies on. |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Phil, Here is my "code" (FWIW). I'm happy to explain if you need it. (and I'd really appreciate feedback, "why did you do that?" included) - this is just for the SDS011 (I have a separate program based on Geoff G's for the VOC (same hardware)). I'll get round to combining with the two sensors in due course). - the guts of it is Tassie Jim's work I just massaged it for my HC-12 network - my network has a GPS up a pole with the weather station sensors - this sends sentences via HC-12s - the Time and Date are updated every 2 hours (with a $AGD_T" sentence) or when any site sends a "$AGFST" sentence - it uses two serial comms ports - you'll need to change the TEXT fonts (the two Geoff G ones are from his VOC Monitor in Silicon Chip or on his website). OK? Andrew (Edit - I've left the typos/formatting errors in my code for your amusement) 'AirQual.BAS 'Based on "AirQual By Jim.BAS" (= TassieJim from The Back Shed) ' SDS011 dust sensor ' serial 9600 8 N 1 5V TTL ' ' device = &HFFFF for all connected devices. 'Fonts #2, #3, #6 (=GeoffG's #8), #7 (=GeoffG's #7) & #8 loaded into Library Dim String Prog(3) = ("AirQual", "v13"," ", "Stn ID=") Dim String StationID = "7" Prog(3) = Prog(3) + StationID 'zzz_to_do: 'Close down properly so it restarts better 'V13: 'Uses a 320x240 LCD - is upside down which means HC-12 aerial points down 'V12: 'Incorporates HC-12 and code from AmbiMon to send FST and receive and process time. 'Sends AGPPM message (zzz need to correct all AmbiMon devices) 'Saves Geoff G's fonts 7 and 8 to LIBRARY as 7 and 6 'v11: 'Supersedes v9 - Stick with Jim's from now on 'AG Changes: ' changed "l" to "L" (3 off in Function CS) Dim String arg$(20) 'The upto 21 arguments in the NMEA-like sentence 'zzz can reduce DIM FLOAT PM25, PM10, PM25Min, PM25Max, PM10Min, PM10Max DIM INTEGER x, readAvailable, sleepTime DIM k$, r$, reportMode$, state$, ID$ dim String OldTime OPEN "COM2:9600,256" AS #3 'Incoming SDS data OPEN "COM1:9600, 1024, HC12In, 4" as #1 'Data in/out HC-12 Cls Date$ = "01-01-2000" 'Enter a dummy date to check it has been updated properly Send_FST 'Tells the network that it is starting up and sends inital values ' 'Gets date and time in return. $AGD_T sentences update these every 2 hours. Print Prog1$;" ";Prog2$ Print "Station ID is "; StationID for I = 0 to 3 Text MM.Hres/2, MM.Vres/2 - 40 + 22*I), Prog(I) , CM, 1,2, RGB(Green) next I pause 3000 'This is to show the ID and allow FST to return date and time (2000 is adequate) For I = 1 to 10 'Should already have the Date and Time this just makes sure if Date$ = "01-01-2000" then Send_FST text mm.hres/2,mm.Vres/2 + 60, "PL.WAIT "+STR$(I),CM,1,2,RGB(CYAN) Pause 1000 else exit For endif next I Cls UpdateTime 'Updates the time on LCD and every minute thereafter 'Every 2 hours the AmbiMon base station sends a Time$/Date$ update x = sendCMD(8,1,0,&HFFFF) ' Duty cycle continuous to get the initial reading PAUSE 1000 x = sendCMD(2,0,0,&HFFFF) ' check report mode x = sendCMD(6,0,0,&HFFFF) ' check state x = sendCMD(8,1,5,&HFFFF) ' duty cycle 30 secs on every 5 minutes OldTime$ = Mid$(Time$, 1, 5) 'MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM_Start_Main_Loop: DO If OldTime <> Mid$(Time$, 1, 5) then OldTime = Mid$(Time$, 1, 5) UpdateTime End If IF LOC(#3) > 0 THEN k$ = INPUT$(1,#3) r$ = r$ + k$ IF ASC(k$) = 171 THEN doRead ' end of data flag rec ENDIF IF readAvailable THEN doDisplay If SleepTime > 0 and timer =>(SleepTime)*1000 then 'Just as it is due to awake check, and confirm that it is then awake Checkstate Timer = 0 end if LOOP 'mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm_End_Main_Loop: ENd Sub CheckState x = sendCMD(6,0,0,&HFFFF) ' check state End Sub 'Checkstate Sub UpdateTime 'Show the time each minute Text mm.Hres -1, 0, Mid$(Time$, 1, 5), RT, 6,1, RGB(Yellow) End Sub 'UpdateTime SUB doDisplay 'zzz can redo to only draw stuff that has changed PRINT TIME$;", PM2.5="; STR$(PM25,4,1);", PM10="; STR$(PM10,4,1);", Mode= "; reportMode$;", State= "; state$; IF SleepTime = 0 THEN PRINT ", Duty= continuous" ELSE PRINT ", Duty= "; (sleepTime + 30)/60;" mins" ENDIF if State$ = "Sleep" then text 0, 0, State$, LT,6,1, RGB(170,170,170) else text 0, 0, State$, LT,6,1, RGB(Green) Endif Text 0, 70, "PM2.5", LB, 6,1, RGB(170,170,170) Text 0, 180, "PM 10", LB, 6,1,RGB(170,170,170) text mm.Hres, 90, STR$(PM25,3,1), RB,7,1, RGB(Green) circle mm.Hres-50, 70, 5,,, RGB(Green),RGB(Green) text mm.Hres/2+20, 130, STR$(PM25Min,3,1), RB,6,1, RGB(Cyan) text mm.Hres, 130, STR$(PM25Max,3,1), RB,6,1, RGB(Red) text mm.Hres, 200, STR$(PM10,3,1), RB,7,1, RGB(Green) circle mm.Hres-50, 180, 5,,, RGB(Green),RGB(Green) text mm.Hres/2+20, mm.Vres, STR$(PM10Min,3,1), RB,6,1, RGB(Cyan) text mm.Hres, mm.Vres, STR$(PM10Max,3,1), RB,6,1, RGB(Red) readAvailable = 0 END SUB SUB doRead LOCAL INTEGER replyMode IF MID$(r$,2,1)= CHR$(&hC0) THEN replyMode = 1 IF MID$(r$,2,1)= CHR$(&hC5) THEN replyMode = ASC(MID$(r$,3,1)) SELECT CASE replyMode CASE 1 ' data PM25 = (ASC(MID$(r$,3,1)) + ASC(MID$(r$,4,1))*256)/10 PM10 = (ASC(MID$(r$,5,1)) + ASC(MID$(r$,6,1))*256)/10 Out$ = "$AGPPM"+","+Str$(PM25)+","+Str$(PM10)+"," + StationID Out$ = CRC$(Out$) Print #1,Out$ Print Out$, Tab(40);"Sent at ", Time$ if PM25Min = 0 then PM25Min = PM25 If PM25 > PM25Max then PM25Max = PM25 If PM25 < PM25Min then PM25Min = PM25 if PM10Min = 0 then PM10Min = PM10 If PM10 > PM10Max then PM10Max = PM10 If PM10 < PM10Min then PM10Min = PM10 ' 'The CO will report "Awake" Checkstate 'Immediately after a "CO" this should report "Sleep" Timer = 0 CASE 2 ' data reporting mode IF ASC(MID$(r$,5,1)) = 1 THEN reportMode$ = "query " ELSE reportMode$ = "active" ENDIF CASE 5 ' new ID 'zzz not used??? ID$ = HEX$(MID$(r$,8,1),2)+HEX$(MID$(r$,9,1),2) CASE 6 ' sleep mode IF ASC(MID$(r$,5,1)) = 1 THEN state$ = "Awake " ELSE state$ = "Sleep" ENDIF CASE 8 ' duty cycle SleepTime = ASC(MID$(r$,5,1))*60 - 30 'For a 5 min duty cycle SleepTime = 270 seconds (= 5*60 - 30) IF SleepTime < 0 THEN sleepTime = 0 END SELECT r$ = "" readAvailable = 1 END SUB Sub HC12In 'COM port directs to here if there are any incoming sentences 'zzz delete unused ones Local Integer II Again4: HCIn$ = "" Line Input #1, HCIn$ If LEN(HCIn$) = 0 then GoTo Again4 If CheckCRC(HCIn$) Then 'CRC Check is OK If Mid$(HCIn$, 1, 6) = "$AGD_T" Then For II = 1 to 2 arg$(II) = Field$(HCIn$, II+1) Next II Print "Old Date:", Tab(11), Date$; Date$ = arg$(1) Print Tab(22), "New Date: ", Tab(32), Date$ Print "Old Time:", Tab(11), Time$; Time$ = arg$(2) Print Tab(22), "New Time: ", Tab(32), Time$ Exit Sub End If Else Print "CRC Fail:", HCIn$, " ", Chksum HCIn$ = "" End If End Sub 'HC12In Sub Send_FST 'Out$ = "$AGFST"+","+Str$(temp)+","+Str$(humidity)+","+Str$(Voltage,0,2)+","+StationID 'zzzTemp = TEMPR(TemprPin) Temp = 0.0 'zzz 'Ex WS RemoteOut$ = "$AGFST"+","+Str$(temp)+","+Str$(humidity)+","+Str$(Raining)+","+StationID Out$ = "$AGFST"+","+Str$(Temp)+",0,0," + StationID Out$ = CRC$(Out$) Print #1,Out$ Print Out$, Tab(40);"Sent at ", Time$ End Sub 'Send_FST Function Field$(s As String, n As Integer) Const delim1 = "," ' set this to the field delimiter Const delim2 = "*" ' set this to the second field delimiter Local Integer i, StartIdx = 1, EndIdx ' get the start of the field in StartIdx For i = 2 To n StartIdx = Instr(StartIdx, s, delim1) + 1 If StartIdx = 1 Then StartIdx = Instr(StartIdx, s, delim2) + 1 If StartIdx = 1 Or StartIdx > Len(s) Then Exit Function Next i ' get the end of the field in EndIdx and extract the field EndIdx = Instr(StartIdx, s, delim1) If EndIdx = 0 Then EndIdx = Instr(StartIdx, s, delim2) If EndIdx = 0 Then EndIdx = 255 Field$ = Mid$(s, StartIdx, EndIdx - StartIdx) End Function 'Field FUNCTION CRC$(Txt$ AS String) 'Returns the Txt$ passed to it with "*hh" added, where hh is the NMEA Hex checksum 'Local String Txt$ Local Integer n Chksum = 0 FOR n = 2 TO LEN(Txt$) 'n=2 makes it skip the leading $ Chksum=Chksum XOR ASC(MID$(Txt$,n,1)) NEXT n CRC$=Txt$+"*"+HEX$(Chksum,2) END FUNCTION FUNCTION CheckCRC(Txt$ AS String) 'Txt is the full NMEA sentence ie "$ . . .*hh" 'Function returns Chksum and CheckCRC = 1 if Calculated CRC = received CRC Local Integer n Chksum = 0 CheckCRC = 0 'zzz Not strictly necessary FOR n = 2 TO LEN(Txt$)-3 'n=2 makes it skip the leading $ and -3 stops before the * Chksum=Chksum XOR ASC(MID$(Txt$,n,1)) 'The standard NMEA checksum calculation NEXT n IF RIGHT$(Txt$,3) = "*"+HEX$(Chksum,2) THEN ' Crc match CheckCRC = 1 Else CheckCRC = 0 ENDIF END FUNCTION 'CheckCRC FUNCTION sendCMD( c AS INTEGER, d AS INTEGER, e AS INTEGER, device AS INTEGER) AS INTEGER LOCAL s$ s$ = CHR$(&hAA)+CHR$(&hB4)+CHR$(c)+CHR$(d)+CHR$(e)+STRING$(10,0)+CHR$(device\256)+CHR$(device AND 255) s$ = s$ + cs$(s$,17)+CHR$(&hAB) PRINT #3,s$; END FUNCTION FUNCTION cs$(s$,L AS INTEGER)' L should be 7 for reply or 17 for command LOCAL n, k FOR n = 3 TO L k = k + ASC(MID$(s$,n,1)) NEXT n cs$ = CHR$(k AND 255) END FUNCTION Edited 2020-03-16 15:08 by Andrew_G |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Phil, I'm also interested in an LED to show when it is "asleep" or "awake". I couldn't get one working off the power to the fan - please let me know if you do. I partially got around this by testing its status ( "state$" above) just before/after it was meant to be asleep or awake and then reporting that on the LCD. Andrew |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Hi Andrew, Just reposting your code for the sake of readability. Also, can you post a pic of you display for the hell of it. Pic is worth a thousand words; & beats deciphering code. Cheers. |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Hi Phil, Thanks for tidying up my "code" - I guess that is what the "Code" button is for?? (Jim's MMEdit formats things to look better so the typos are less apparent.) Here are two pictures:   The display shows current P2.5 and P10 values, in larger font, and the minimum and maximum values to date (Cyan and Red). The grey word "Sleep" changes to a green "Awake" when the sensor is working. The top left time is from my HC-12 network as described above. There is no graph (yet) but I graph all my HC-12 inputs on my PC. The other pic shows you can just fit both sensors, an HC-12 and a LCD BackPack in the box. There is a bend in the tube feeding the SDS011 (and its covered in black heat shrink) to reduce the light getting to the sensor. I've enlarged the 4 holes at the back of the box to exhaust air from the SDS fan. I have yet to isolate the VOC sensor from the air inside the box. OK? Andrew |
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Quazee137 Guru Joined: 07/08/2016 Location: United StatesPosts: 572 |
If a good detection system can be done low cost it could be used to turn on electrostatic based air purifier in rooms not being occupied. One that is low current and very high voltage would pull the particles out of the air. This would even help slow down air born viruses from spreading. Here is an updated page Air Ionizers Just today's rambling thoughts. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Interesting, I have an Ozone Generator on my Spa. Built it from components from Ali, with output potentially 10x above the overpriced commercial offerings for the task. It runs at a low level, but does a superb job. Phil. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Andrew, Good to see the pics & particularly the assurance that I'm not the only one that still uses strip board. I'm sure I could learn to do my own PCB's, but work has me sitting behind screens enough in a day, let alone learning another PC based task. Still trying to get my head around the graphs module here, but will get back to it. Phil. |
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lew247 Guru Joined: 23/12/2015 Location: United KingdomPosts: 1702 |
Has anyone seen these? Enviroment Sensor  and Pm1, PM2.5, PM10 Particulate Sensor  They work really well, Python code is Here With a Pi Zero+ I'm sure MM could do a great job displaying, storing and uploading the results Enviro + Air Quality features BME280 temperature, pressure, humidity sensor (datasheet) LTR-559 light and proximity sensor (datasheet) MICS6814 analog gas sensor (datasheet) ADS1015 analog to digital converter (ADC) (datasheet) MEMS microphone (datasheet) 0.96" colour LCD (160x80) Connector for particulate matter (PM) sensor (available separately) Pimoroni breakout-compatible pin header pHAT-format board Fully-assembled Compatible with all 40-pin header Raspberry Pi models Pinout Python library Dimensions: 65x30x8.5mm PM1.0, PM2.5 and PM10.0 concentration in both standard & enviromental units Particulate matter per 0.1L air, categorized into 0.3um, 0.5um, 1.0um, 2.5um, 5.0um and 10um size bins I'm sure the right person could convery the Python code to Basic to use with Pi-Cromite? Edited 2020-03-18 21:04 by lew247 |
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| BrianP Senior Member  Joined: 30/03/2017 Location: AustraliaPosts: 292 |
Strip board ist gut!!!  B |
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| Andrew_G Guru Joined: 18/10/2016 Location: AustraliaPosts: 847 |
Phil, For such a simple circuit - yes! I'm hanging out for a 3D printer that can do simple PCB-like boards. Now that would be good Andrew |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Hi All, Received the Sensirion SPS30 I ordered a week or so back.  First stumbling block was that it's interface connector is a ZHR-5. 1.5mm pin spacing.... Received the plugs & pins from RS today & managed to get it connected to a USB port via the CH340 USB-Serial adaptor that came with my SDS011. Sensirion's Evaluation software was quite happy to connect to the device & read it regardless of me not having their USB device. Won't do too much with it of the SDS011 just yet as I'd like to get my head around Geoff's graphing code first so I can add more traces.  |
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| CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2076 |
I never really like strip board, only used it for basic stuff. I preferred paperboard with the land around each hole or eurocard style ones laid out for ICs. Then backwire from a net list. These days, I don't do either (for single sided stuff), I etch a single PCB. Circuit ends up in Eagle anyway, lay-up a board - which I find quite therapeutic. Then save out the track, pads & vias image of the board as a PNG, covert to SVG with Inkscape and cut it onto a bit of black-painted board and etch. The export, convert, cut, etch takes less than an hour and I have a guaranteed working hookup - barring mistakes. I did two yesterday alone. I lay the board up as two-sided, avoiding the top as much as possible and then use that to top-links where I get stuck. Can't do really fine stuff though as my laser etcher is a only cheapie, but it can just about do down to tracks of 32 thou. Prefer 50 thou as a standard which give a very robust board. |
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