Reading absolute pressure with Bosch MAP sensor with Arduino #1 (actual measurements)

Practical way to read absolute pressure with Bosch MAP sensor and Arduino. My Bosch MAP sensor (0-2.5bars) number: 0281002593 or 8200225971 (amazon UK): https://amzn.to/2Bsykx7 or ebay: https://ebay.us/NvfSBa If you find this video useful, buy me a coffee: https://www.paypal.com/paypalme/morem... All my car-related purchases: https://www.amazon.co.uk/shop/moremol... This video shows how one can use a second-hand car Manifold Absolute Pressure (MAP) sensor with Arduino. One can use it to measure absolute pressure, for example atmospheric pressure or any other source. The formulae behind the sensor and the ones in the code are explained in the second video. Arduino Code. Angle brackets or less than do not get out very well. So, I have put LESS_THAN instead of the angle bracket. int mapsen = 0; // Set MAP sensor input on Analog port 0 int NUM_SAMPLES=300; // number of samples float sum = 0; // sum of samples taken int sample_count = 0; // current sample number float input_voltage = 4.90; //measured with multimeter void setup() { Serial.begin(9600); } void loop() { sum = 0; sample_count = 0; while (sample_count LESS_THAN NUM_SAMPLES) { sum += float(analogRead(mapsen)); sample_count++; delay(0.5); } float out_voltage = (sum / NUM_SAMPLES * input_voltage) / 1024; float Pabs = out_voltage*2705.8824/input_voltage-16.4706; //absolute pressure in mbar //Bosch 20-250 kPa MAP sensor min pressure measured: 200mbar with 0.4V (typical) //Bosch 20-250 kPa MAP sensor max pressure measured: 2500mbar with 4.65V (typical) //Bosch 20-250 kPa MAP sensor linear model formula is: //Ua=Uv*(Pabs*0.85/230 + 0.0061); Uv=supply voltage; Ua=output voltage; Pabs is absolute pressure //Ua is proportional to the supplied voltage, so Ua is always divided by Uv //from this formula the linear model for absolute pressure in mbar: //slope = dy/dx = (2500mbar-200mbar) / (Ua_max-Ua_min)/Uv_input = 2300mbar / (4.65V-0.4V)/5V = 2300/0.85 ~2705.882353 //generalised linear model y=ax+b; then the y-intercept (b) is calculated as follows with Uv=5V: //200=(0.4/5)*(2300/0.85)+b; b=200-(0.4/5)*(2300/0.85)=200-0.08*2705.8824=200-216.4706=16.4706 //slope = dy/dx ~ 2705.8824; y-intercept ~ -16.4706, so y=ax+b or y(abs pressure in mbar)=2705.8824*(Ua/Uv)-16.4706 Serial.println(Pabs); //Serial.print("\t"); //Serial.println(out_voltage,4); } Disclaimer: Use the information provided in this video at Your Own Risk. More molecules provides this video for informational purposes only and assumes no liability for any damage or loss incurred as a result of the use of the information or tools presented in this video. The information provided here may contain inaccuracies and more molecules cannot guarantee the correctness or reliability of the content. As an Amazon Associate I earn from qualifying purchases. As such I have included affiliate links that may earn a small commission if you click through and make a purchase. I am an independent youtuber and I am in no way influenced by any advertiser or commercial initiative. As an Ebay Partner when you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.