We originally thought of a PC & slave board but realized how difficult it is to maintain a stable PC in the back of a truck; our sun temperatures exceed 50 °C in summer, voltage levels, efficient watchdog, operating system damage due to sudden crashes, etc.; PCs greatly facilitates wifi, internet and databases but they are difficult to use outdoor on a 24x7 basis. We are open to continue with this model if you provide us a viable solution.
Our model is to have a board that we can install hardware as needed depending on the user level, we have four user levels:
Cars: Utility vehicles without propane meter, we are interested in passive gps tracking and automatic download to our database on GPS detected Wi-Fi hotspots. Bobtails: Propane delivery trucks with tank and meter, passive GPS tracking, GPS enabled Wi-Fi hotspots to upload and download data, 2 solenoids to run the meter, Adc12 for pressure and temperature of the tank and pump, Adc14 for tank magnetorestrictive level gauge. Stations: Just like a regular gasoline station, upload/download internet data by Wi-Fi, 2 solenoids to run the meter, Adc12 for pressure, Adc14 for tank magnetorestrictive level [url removed, login to view]: Propane cylinder filling station using up to 4 concurrent scales, 4 solenoids, 4 Adc 12 and 2 Adc14 for tank magnetorestrictive level gauge. Biometric controls are very desirable to prevent password theft and vandalism.
Software development will be primarily focused on sample code on how to use Wi-Fi, internet, interrupts and analog/digital ports; the low-level utilities that will be required in the main program in addition to consultancy on general design concepts but it does not include developing the whole system. We are interested in using fram, we consider it very reliable.