USB SPL Meter with RaspberryPI - Raspberry Pi Q&A, Help & Troubleshooting

is it possible to use USB SPL Meter with Raspberry Pi to detect high noise level 30-130 dB for an IoT project? which one is compatible for RPi?

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MHL to VGA

Are there MHL to VGA adapters available that are know to work with the 4x?
Or is MHL standardized enough that i can pick any MHL to VGA without any worrying about working?
I know HDMI is usually better but my HMD (tac eye) takes only VGA or SVideo (though SVideo quality really suxx, its only on for NV not for data).
Also I see some MHL to VGA adapters have a secondary USB port, can this be used only as client or could I somehow connect a pointing device to my phone?
If I were you i would take MHL to HDMI cable and then HDMI to VGA. Reason is simple. Sometime you may want to connect your phone to new TV so you will need HDMI as it is standard port.
Secondary USB port is microUSB and it is used to charge phone while conected to TV (at least thats how it works with MHL to HDMI cable).
Stevic Milos said:
If I were you i would take MHL to HDMI cable and then HDMI to VGA. Reason is simple. Sometime you may want to connect your phone to new TV so you will need HDMI as it is standard port.
Secondary USB port is microUSB and it is used to charge phone while conected to TV (at least thats how it works with MHL to HDMI cable).
Click to expand...
Click to collapse
Well, for me this would than look like: MHL-HDMI adapter connected to a HDMI-VGA adapter connected to VGA-"Proprietary HMD Port" thats in used space and weight more for the adapters than for the phone and HMD. As i intent to wear this on my body thats rather not cool. Also the HDMI-VGA adapter will want some juice what will be an additional drain on my batteries.
The "VGA-"Proprietary HMD Port" is passive, so if I like the setup I will probably cut the MHL-VGA adapter open and attache the signal lanes directly to a fitting plug for my HMD.
Also I don't own a TV just a 30" WQXGA Dell Monitor with a Duallink DVI port its one of the old models that had only Duallink DVI, no scaling no DVI no VGA and no other ports.
An other issue would be how to control the phone when it in my pocket, how can I attache some pointing device and would this even work with android OS?
Or would I have to wait for an unlocked bootloader and this cool ubuntu on phone projects that provide a full ubuntu desktop?
PS: is the micro usb port on the adapter only used for charging or is there still a USB signal on it?
David
If i got you right, you want to control phone, connected to PC monitor, over HDM goggles?
You can try something like this https://code.google.com/p/androidscreencast/
It is a software that enables remote control of your phone over WiFi, so if your goggles work on PC it should work here to. It does the same job as the cable connection (MHL to VGA)
As for the MHL to VGA adapter you have 4 connectors:
1) male microUSB (one you connect to your phone)
2) female microUSB (charger or power supply, so it doesn't use phone battery)
3) female VGA (for monitor)
4) 3,5 audio jack for sound
Stevic Milos said:
If i got you right, you want to control phone, connected to PC monitor, over HDM goggles?
Click to expand...
Click to collapse
Not exactly I don't want to use a PC at all. I want to connect the HMD (Vuzix-Tac-Eye-LT-Monocular) directly to the phone and use some pointing device or mini keyboard to control the phone.
I have the adapter and a problem,
the phone is only giving out its native screen resolution, my HMD cant handle.
How can I change the resolution so SVGA ?

[Q] RPi GPIO ribbon pin numbers??

Hi! I've just built a Raspberry Pi Gameboy by with parts and instructions from Adafruit, with all the controls hooked up tp GPIO pins. I was wondering specifically if anyone knew what wire numbers on the gpio ribbon corresponded to what pins on the Model B's gpio. For example, would Wire #3 correspond to GPIO pin #6? Or something like that. I need this information to map the keyboard controls using Adafruit Retrogame, because wire numbers on the ribon don't seem to be the same as the GPIO numbers they're connected to. Any help would be appreciated!
Gameboy project: search Adafruit PiGrrl (Grrl is not a typo in this case) - First Result
GPIO ribbon: Go to adafruit . com / products / 862
I'm apparently not allowed to post links yet.
EDIT: Fbcp's framerate is so low because it screenshots the HDMI output and transfers it to the mini screen about every 25ms, giving about 28FPS. Any way I can change the delay?
Go to raspberry.org and look at the pin out for the gpio header.

Raspberry pi on car dvd touch screen

Hi all
Hope I'm posting on correct place
I am totaly new to this (the forums and raspberry pi)
I would like to know if it ia possible to conect my raspberry pi2
To my cars after market dvd player via the composit
Cable and then use the dvd players touch screen for the
Raspberry pi.
Is it possible?
Thabks in advanced.
Immanuel89 said:
Hi all
Hope I'm posting on correct place
I am totaly new to this (the forums and raspberry pi)
I would like to know if it ia possible to conect my raspberry pi2
To my cars after market dvd player via the composit
Cable and then use the dvd players touch screen for the
Raspberry pi.
Is it possible?
Thabks in advanced.
Click to expand...
Click to collapse
Only the display will be shown on Your DVD player if Your DVD player supports composite cable input. You cannot control the Raspberry Pi using composite cable because AFAIK, the composite cable supports only audio/video and that too only one way (3.5mm to RC).

Which GPIO pins are 0V at startup?

So I'm doing a project today with the Raspberry Pi 2 Model B and I realized that some (not all) of the GPIO pins output 3.3V at startup (I mean the data pins, not the power output pins). I cannot have it output 3.3V since I'm using the RPI to control a quadcopter and that would cause a mess if the motors ran at full speed at bootup. So do you guys know which pins are 0V (off) at startup and I can control using WiringPi?

Need some help to choose the best Pi model

Greetings everyone.
I need some help regarding Raspberry PI.
I want Raspberry PI that can play simple sound during the start-up to connect it to the car using a usb outlet.
so the requirement for the Raspberry PI is :
-Can be powered by 12v usb outlet.
-3.5 headphone jack
-ability to install external speakers
-Small storage size (1GB)
So what is the best Raspberry PI model that can fill full those requirements?

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