Re: arduino grount to chassis ground??
You mean, the probe is able to break through this oxidized layer. Probes should have a very sharp point. Enen if you use a (soft) copper wire, you will probably measure conductivity, the question is if this conductivity will last during the lifetime of the machine.
In Europe this toothed washer is a safety requirement.
Re: arduino grount to chassis ground??
Quote:
Originally Posted by
tkms002
I am using a laptop that is not always plugged in.
Which changes things because most laptops don't even have a third pin for ground (at least in Oz). So you need a way of locally grounding your arduino and, indeed, the laptop via the USB connection so everyone's talking the same reference zero voltage. Star point ground, even consider soldering a nice fat wire to the board next to the USB connector's shield to that star point as a low impedance path for normalising voltages from the laptop.
Quote:
Originally Posted by
hfjbuis
You mean, the probe is able to break through this oxidized layer. Probes should have a very sharp point. Enen if you use a (soft) copper wire, you will probably measure conductivity, the question is if this conductivity will last during the lifetime of the machine.
In Europe this toothed washer is a safety requirement.
Most places it is. Don't forget that brushing a probe on continuity sense has a very low current and thus minimal voltage drop across the connection. Crank up the current and you may find that the connection to an oxidised ali surface creates such a high voltage drop it becomes next to useless.
Re: arduino grount to chassis ground??
Quote:
Originally Posted by
hfjbuis
You mean, the probe is able to break through this oxidized layer. Probes should have a very sharp point. Enen if you use a (soft) copper wire, you will probably measure conductivity, the question is if this conductivity will last during the lifetime of the machine.
In Europe this toothed washer is a safety requirement.
thanks I will add them
Re: arduino grount to chassis ground??
Quote:
Originally Posted by
dharmic
Which changes things because most laptops don't even have a third pin for ground (at least in Oz). So you need a way of locally grounding your arduino and, indeed, the laptop via the USB connection so everyone's talking the same reference zero voltage. Star point ground, even consider soldering a nice fat wire to the board next to the USB connector's shield to that star point as a low impedance path for normalising voltages from the laptop.
Most places it is. Don't forget that brushing a probe on continuity sense has a very low current and thus minimal voltage drop across the connection. Crank up the current and you may find that the connection to an oxidised ali surface creates such a high voltage drop it becomes next to useless.
my laptop does have a third wire on the charging cord. When I created my electronics box I added a grounded 120v power outlet that I plug the laptop into.
So, I will run a wire from the Arduino GRD to my common ground(a bus bar). I will add star washers in between the ground bus and the chassis.
Thanks