Need to control a relay based on a few inputs and conditions.
Small device like Arduino Pro Micro
Atmel MEGA328P processor
Two analog 0-5v inputs:
1. CO2 sensor (actually 0-4VDC output but we'll make it easy and call it 0-5 = 0-255)
2. Light sensor (photocell -analog input level TBD)
2 inputs connect to a SPDT switch so use can select between three CO2 levels
1 input to override light sensor
1 input to select that we will use the light sensor override input
Device will connect to 5VDC, GND & V-OUTPUT from CO2 sensor (0-4VDC)
0-4V = 0-2000ppm CO2
want to be able to control CO2 level so that the level can be set to 1300ppm, 1200ppm & 1100ppm with differential of 200 (hysterisis)
If set for 1300ppm, the relay will turn ON when the CO2 level drops below 1100 and turn OFF when the desired level of 1300ppm is reached.
If set for 1200ppm, the relay will turn ON when the CO2 level drops below 1000 and turn OFF when the desired level of 1200ppm is reached.
If set for 1100ppm, the relay will turn ON when the CO2 level drops below 900 and turn OFF when the desired level of 1100ppm is reached.
Relay only turns on when photocell detects light (no CO2 needed in the dark)
For safeguard (sensor failure), the relay will not turn on of the CO2 level detected falls below 300.
I know that for somebody who does this programming all the time can do this in 15 minutes but for me, it would take a day or two and I still might not get it right! I would like somebody to write this code for me so that I can change the inputs outputs levels, etc (please leave comments in the code so I know what is what). Any future tweaking will be on an hourly basis with a minimum (I know nobody wants to get paid for five minutes).
I'll be using an Arduino UNO & breadboard for testing so if we can go ahead and output on digital out pin 13
Digital in from select switches pins 2,4,7,8
Use analog pins A0 for CO2 levele, A1 for input from photocell (straight connection 5v through cell)
(I'll make changes in I/O if needed - I can figure that out myself!)
Might later need to add an I2C display to show CO2 level and relay state, etc - Not needed for current project because CO2 unit has display onboard.
I don't mean to discriminate but my only language is english so need designer with good english writing ability so we can effectively communicate.
Please only bid if you have time to do this immediately.
Thanks! Dan Weddle / DX Hydro