CO2 Detector

5 years ago

Open source license: Public Domain

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Description

Uses MH-Z19 or MH-Z16 CO2 detector and DHT-22 (or DHT-11) Temperature/Humidity sensor to give air quality readout and actuate relays if CO2 level goes above 1000ppm (Lo Alarm for turning on extraction fan) and High Alarm at 5000ppm to sound an alarm etc. Uses large 20 x 4 HD44780 display

Hardware is 100% Complete. Software is about 90% Complete (Works but untested and buzzer/silence not yet worked out) Will post code back here and on my website when 100% have attached Work In Progress MPLABX XC8 Code (incomplete but which will display CO2 levels)

Has spare UART brought out to header to attach MODBUS/WiFi/Bluetooth if required. PCB footprint suitable for mounting in standard industrial 158x90x65mm Plastic Enclosure

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BOM

ID	Value	Qty.	Package	Components
1	ICSP	1	1X05_LOCK	J2
2	BUZZER	1	BUZZER-12MM-NS	SG3
3	RLA-LO-ALM	1	REY5-19.0X15.0X15.0MM	K1
4	MH-Z19	1	MH-Z19	U1
5	RLA-HI-ALM	1	REY5-19.0X15.0X15.0MM	K2
6	HLK-PM01 - AC-DC-converter 5V 600mA	1	POWERSUPPLY MODULE HLK-PM01	U2
7	fuse	1	FUSE-5X20-PCB	U4
8	ALM HI	1	SCREW TERMINAL 5MM 2P	RLA-HI
9	ALM LO	1	SCREW TERMINAL 5MM 2P	RLA-LO
10	11.0592Mhz	1	HC49UP	Y1
11	mh-z16	1	JST-PH7	U5
12	HT1117-33_SOT223	1	SOT-223	U8
13	SMD1210R075SF	1	F1210	F1
14	240VAC	1	SCREW TERMINAL 5MM 2P	PWR
15	100nF	4	C0805	C8,C1,C4,C5
16	IRLML2502TRPBF	3	SEEED-SOT-23	Q1,Q2,Q3
17	HI ALM	1	SEEED-LED-0805	D1
18	LO ALM	1	SEEED-LED-0805	D2
19	10K	1	R0805	R3
20	1K	5	R0805	R2,R4,R5,R6,R7
21	100R	1	R0805	R1
22	22pF	2	C0805	C6,C9
23	DHT22	1	SNR4-2.54-15.5X12.0X5.5MM	U10
24	PIC18F23K22	1	SOIC-28	U6
25	PWR	1	SEEED-LED-0805	D4
26	1N4007	2	SEEED-DO-214AC	D3,D5
27	ERM2004 (buydisplay.com)	1	HDR1X16	X1
28	S20K250	1	CHOKE_HORIZONTAL_RM10MM_REVB	VAR1
29	5.1K	1	R0805	R8
30	panel	1	HDR1X4	U3