Reading current

Bea926

[noparse][[/noparse]CLEARED]

Post Edited (Bea926) : 4/23/2009 9:54:58 PM GMT

Phil Pilgrim (PhiPi)

How much current, approximately? How much voltage can you stand to drop to accommodate the measurement?

-Phil

Bea926

The idea is that the Stamp will be reading between 1 to 3 amps at any given time. The stamp is connect in parallel to a resistor to read a differential across that resistor. The current will diminish in a (1/x)-like function (with some variance of course). My plan is to take a reading every 5 minutes and keep a "log" of about 4 plots. These 4 plots will be compared to one another right after taking a value down. If the values are not within a certain range, it will delete one of those values and substitute it 5 minutes later. When the 4 plots logged are within a range of each other, the Stamp will cut power to a connected relay switch and kill the current. The Stamp will not take readings anymore and the relay will remain off until a momentary switch is activated.

I hope this clarifies what you can assist me with. Thanks in advance!

vaclav_sal

Connecting a resistor in parallel with your Basic Stamp power source will not give you required reading. You need to connect the resistor in series with the power source and read voltage across this resistor. Than calculate the current and power.
Of course you could just connect the ampermeter in series with the power source and than calculate the power input that way.
Either way – check the datasheet for the PIC processor and datasheet for the Stamps regulator. You may readjust your estimated current accordingly before you even start your experiment. (Somewhere around 50 mA would be my guess – I have newer measured it or looked it up).