Hello guys.

For my second year project i'm working on a control circuit for a solenoid valve which is attached to an accusump of a car. Basically the circuit has to monitor when the pressure in the oil tank drops, when it does the solenoid valve has to be opened to allow oil from the accusump to flow to the cars engine.

I've only just begun the project and only have a vague idea of the layout;

I'm going to put a pressure sensor into the oil tank to monitor the pressure. Then the signal from the pressure sensor will be connected to a microcontroller (at the minute I think thats going to be a PIC16F819 as it has analog and digital input ports).

Then i'm going to program the chip so when the signal from the pressure sensor reaches a certain threshold, it will put one of the output ports of the chip high. From the output port I will use a simple transistor circuit to amplify the current to a useable level by the solenoid valve. The current will then open the valve permitting the oil flow.

I have a few questions:

1. Firstly, have I overlooked and/or omitted any critical process?

2. Secondly, referring to the signal from the pressure sensor. What will I have to do to it before I can connect it to an input port of a PIC Chip?

Any feedback is greatly appreciated, thanks.

 

"when the pressure in the oil tank drops"
in my best hair splitting mode, isnt the accusump a reserve oil supply,(would the oil tank be pressurised?) so wont you be monitoring the engine oil pressure,?

"Secondly, referring to the signal from the pressure sensor. What will I have to do to it before I can connect it to an input port of a PIC Chip?
presumably this will be an analogue sender varying between 0 to 12 volts or can it be treated as a variable resistor,
d

 

ps
im a learner, but a couple of simple points before the expert reply,
voltages will be critical so include a voltage reg,
a diode in the solenoid coil circuit,
sound like youve got the hard work- doing the programming.
d

 

Yes tibbles, you're correct about monitoring the engine oil pressure, I didn't phrase that part very well sorry.

The voltage regulator is going to have to be implemented before the input reaches the microcontroller, is this correct?


Thanks for your input tibbles.