Modifying a Blood Pressure Pump to Switch an LED

[budm]

Re: Modifying a Blood Pressure Pump to Switch an LED

See post 15.

[capwizard]

Re: Modifying a Blood Pressure Pump to Switch an LED

You're a PRO!

[Winston Chadwick]

Re: Modifying a Blood Pressure Pump to Switch an LED

Dump valve impedance is 40 ohms.

There is no resistor between the ATMega128A and Gate 2 of Q1. Gate 2 is 5V above ground potential when the dump valve is closed.

R4 is connected to pin 2 (trigger) of the 555 timer.

[budm]

Re: Modifying a Blood Pressure Pump to Switch an LED

What is the supply Voltage for the valve, 12V? Just trying to find out how much current is being used by the valve.

[Winston Chadwick]

Re: Modifying a Blood Pressure Pump to Switch an LED

Supply for the dump valve is 6.27V from the voltage regulator

[budm]

Re: Modifying a Blood Pressure Pump to Switch an LED

That is odd Voltage for regulator.
That will be about 157mA for the coil.
Based on the resistors as shown in the circuit, that is about right, around 6VDC.