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3
votes
4answers
187 views

How to read values from an clamp-on ammeter with an raspberry pi?

I want to use a clamp-on ammeter (like this one) to detect whether a table saw (230V) is switched on or not. The clamp-on ammeter is meant to be used with a volt meter and has an 1 mVAC / A output ...
0
votes
0answers
55 views

Measure input voltage of Raspberry Pi B+ running Ubuntu

I just learned that a red flashing LED indicates voltage below 4.63V on a Raspberry Pi Model B+. Thus, the Pi seems to "know" about it's input voltage. So my question is: Is there a command to ...
0
votes
1answer
60 views

Does RB URF02 ultra sonic sensor give false readings?

There's only 1 raspberry pi shop in my country and he offers only two ultra sonic sensors HC - SR04 and RB URF02 there's a pdf on the pages I linked to for more information. RB URF02 is so much more ...
0
votes
2answers
7k views

Count RPM/Frequency/Pulses on GPIO ports (Maximum?)

I'm planning to count the RPM of a RC Car which is controlled with a PI B+. But while planning the question occurs, how to count the RPM. My Idea is via a Sensor, which gives a Pulse every Round, and ...
1
vote
1answer
1k views

Measuring frequency via GPIO

I'm trying to input the frequency of a 3.3V square wave on a GPIO pin as a program feedback parameter. The input frequency range would be 1000 to 100,000 Hz and data polling would happen at 30 Hz. ...
1
vote
1answer
1k views

How to measure DC current RPi?

I have recently bought a Raspberry Pi, and I would like to be able to measure the current flowing through the circuit in our Greenpower electric racing car. It would also be useful to record this for ...
2
votes
1answer
78 views

Can GPIO measure 3-10ms input spike?

I want to measure speed with one infra gate. The width of the bypassing object is known therefore I could calculate the speed. However the infrared gate would be interrupted only for 3-10ms. I ...
0
votes
1answer
209 views

How to measure mains frequency safely via GPIO

I would like to measure the mains power (120vac/60hz) to know precisely when the voltage drops to 0, but in a safe manner for the pi - one solution would be to use a high-value resistor bridge that ...
1
vote
1answer
57 views

Mesure weight using force [closed]

Is it possible to use this force-sensitive resistor to measure weight between 10g-5kg(0,4oz-176oz)?
1
vote
1answer
4k views

Are my GPIO ports not working?

On my Raspberry Pi, I tried to do some experiments with GPIO, without success. Measuring the voltage between GND and GPIO11, for example, always helds a result of 0. I am using /sys/class/gpio ...
11
votes
3answers
5k views

How do I measure the current power consumption?

Is it possible to measure (with software, like powertop) the current power consumption on my Raspberry Pi?
5
votes
3answers
3k views

How to detect whether there is voltage between two points via GPIO?

I'd like to detect whether an external device is switched on or off. I found two pins where there should be 5V between in the first case, but the voltage may vary a bit and I don't wont to break the ...