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-1
votes
1answer
51 views

Not able to use Raspberry pi as a FM transmitter

I have refered to this video https://www.youtube.com/watch?v=6smyUoLugsg .The problem is, in it he has used a Raspberry pi (first model). I tried the things he told me but it wouldn't work. I urgently ...
0
votes
1answer
51 views

How to measure the frequency of the audio output

I was wondering how I can measure the frequency of the audio output of my raspberry pi. Currently I am trying to create a script to control an RGB led to the music that is being played through the ...
0
votes
1answer
52 views

New Raspberry Pi SPI Interface Question

I was looking at the new Raspberry Pi. I wanted to know if the SPI Interface will be able to sample at a higher sampling rate. Does anyone have any information on this? According to this page, the ...
0
votes
0answers
81 views

Raspberry Pi Frequency Calculator

I'm trying to make a simple program that calculates the frequency at a pin on the board. I'm using Python for the programming. I wrote two different programs and they gave the same (wrong!) results. I ...
0
votes
2answers
308 views

Underclock raspberry pi without rebooting

I want to reduce the frequency of operation of my raspberry pi without rebooting. Is there a way to do it ?? I know I can change the frequency by changing the config.txt but it requires a reboot.
1
vote
1answer
146 views

How to access SPI on Raspberry Pi B+

I tried searching here and other places. What is the best way to access the SPI and get the fastest speed out of it. My project involves interfacing the Pi with an ADC that is rated for 5Msps ...
2
votes
2answers
126 views

What is the maximum frequency to count the pulses?

I am new to Raspberry pi. I have an input of continuous pulses. Each pulse width is around 100 nanoseconds . I need to count the pulses for 100 microsecond. Is it possible to do this? Please ...
1
vote
1answer
305 views

how to generate smooth frequency ramp

I want to drive a stepper motor driver hardware by its pulse and direction inputs. I need to use a ramp function in order not to make stepper motor stuck. I need to increase the pulse frequency ...
0
votes
2answers
3k 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 ...
0
votes
1answer
596 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. ...
0
votes
1answer
160 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 ...
3
votes
2answers
782 views

Problems with Pifm legality

There is a lot of discussion online about whether using Pifm is okay because it is low powered, or whether it is very bad because the square waves cause a lot of interference outside the FM band. ...
2
votes
2answers
411 views

PiFM not transimmiting to some frequencies

I was playing with the PiFm on my Pi and successfully transmitted the sound.wav on a specific frequency. That is 94.5 . But when I am trying to do the same on 89.7 , it does nothing. I changed ...
1
vote
2answers
54 views

Why don't I need time:sleep() for talking with a 10MHz chip?

I'm learning to control a MCP4131 digital potentiometer with the RPi. I've successfully used the MCP4131 by sending my data to the SDI pin, and then a HIGH value to the CLK followed by sending a LOW ...
2
votes
1answer
934 views

ADC for ultrasonic frequency recording?

I'm trying to create a prototype using a breadboard that is able to record sounds at the ultrasonic frequency range. I am looking into purchasing this microphone. The problem is that the Raspberry Pi ...
2
votes
1answer
798 views

Set HDMI refresh rate

I would like to set my HDMI refresh rate to 100 MhZ as supported by my TV, however using the code below always set it to 60 MhZ: hdmi_group=1 hdmi_mode=40 Any idea why or suggestions on how to ...
4
votes
1answer
4k views

How does the RF/FM GPIO transmitter hack work?

A while ago, a few guys figured out that they could transmit FM signals using the Raspberry Pi's GPIO ports, and another person realized that he could use the RasPi for controlling his home automation ...
3
votes
1answer
102 views

Power consumption and instruction cycle frequency

I am making a small, mobile device that depends on batteries. It will only require a high CPU frequency occasionally and is at a low frequency the rest of the time. The default frequency is 700MHz. ...
0
votes
1answer
939 views

I²C frequency changeable?

Is the I²C frequency meanwhile changeable? I read a few articles a while ago, that the frequency is not changeable.
0
votes
2answers
202 views

How can I change the frequency?

I would like to change the frequency of the RPI, how can I do that, I'm using low level programming. Also how can I get the used memory and free memory?