Turn on/off screen or fast boot

Hi,

My plan was to use my RPi as a bus-timetable station at home. So when I enter my hall I want the RPi to show when the next bus departures from my nearest stop. And everything works just fine. But, the problem is the boot time. It takes about 1 minute from when I power on the RPi to the timetable being shown. And I want it to be rapid, like 5 seconds. Therefore I am planning to use a motion detector that activates a power plug and then just the screen turns on. So that the RPi is always on.

So I wonder, is it possitble to do that? If so, how? Its a RPi 3 I believe and with the official touchscreen mounted. The motion detector thing with power plug is already done. I just wonder if it is possible to just power on the screen with it, and how I should proceed in that case.

OR just a rapid as hell boot. All I need is a full screen web broswer without mouse pointer or anything else.

Toggling GPIO pins

I have been looking everywhere and haven't found any code that'll just let me turn a GPIO pin on or off! I have the raspberry pi 2b, and I have a small fan plugged into GPIO pins 4 and 6. 4 is a power pin and 6 is a ground pin. I want to be able to turn my fan on and off in the command line, how would I do that?

Looking for suggestions on a motor

Hi! I have some experience coding, but I am completely in the dark about electronics. I'm hoping someone here can help point me in the right direction.

I am working on a design for a mobile device for visually impaired users that will output info either as audio or braille. My goal is to make an example device, then make the design open source for others to build & experiment with. I'm planning on using a Raspberry Pi Zero W, and most of itis straightforward "Buy these parts & put them together."

Where I'm stuck is: How should I power the braille display? Braille is a series of characters coded into 6 cell blocks. Readers glide their fingers over the cells & feel the position of the dots to tell what they are reading. I plan for the final display to be 8 different cells, so that's 48 pins.

The pins just need to be able to move up when needed, then back down when not needed. They need just enough pressure for someone to hold a finger over them. I haven't yet decided what to use for the pins, but I am thinking something the width of the wire in a paperclip. My current thought is to have a motor that can turn a shaft, which would be connected to a gear, connected to an arm that raises or lowers the pin (Basically, and upside down sewing machine.)

I've done some reading on servo and DC motors, but I wasn't able to figure out if either would be enough or overkill for the power I'd need. I'll be continuing my search in the meantime.

Which led matrix to use

Hello I trying a project with a rasp b+. I hope that I would be useful for the rasp zero, but I'm already in the develop time.
I just have a thermostat telegram controlled with WiFi. Not to much complex but enough for my interest. It takes a sensor value and decides if turn off or on a relay. So I need some gpio for this use. I would like to add a led matrix in order to show current temperature and humidity, but I'm in doubt about the gpios they need to work. I would need to show 2 number, a coma, another number and the Centigrades symbol or percent one.
How many gpios I would need?

Zero4U USB Board

Please forgive me if this has already been covered elsewhere, however, I cannot seem to find any information.
I am the proud owner of the Raspberry Pi Zero W, and, I am wondering if the Zero4U USB board, is compatible. Only having 1 USB port is a bit annoying.

Access USB drive shared from one RPi from another RPi?

I have a 2-drive level 1 RAID running on a dedicated RasPi 3. I'd like to access the content in said RAID from another Banana Pi which is running as a Plex server. I can access the RAID NAS from my Macs in the house to load the content, but when I edit my fstab on the Banana Pi, do I treat the RAID as an EXT4 drive (that's how the drives are formatted)? Do I use Appletalk? (it's running netatalk to talk to the Macs)... Do I need to install NFS or is that redundant/unnecessary? Is CIFS involved? The mount command and fstab entry will somehow need to incorporate the login and password for the RPi RAID NAS computer.

Using Pi3 without keyboard

Hi!
Up until now i have been using a wireless keyboard for all my pi uses. Unfortunately, i forget it at my other place and now I'm not sure how to use my pi.
I have a wireless mouse and a Snes usb controller but the pi didn't recognize then.

Is there any way to have the pi recognize one of them?

Can I accomplish this with a Pi?

Hi all,
Whilst I work in IT, I am a beginner when it comes to coding, and I haven't done anything with a Pi. I do however have a "thing" I'd like to build, and am wondering if the Pi can do what I'm looking for.

I have an amateur motor-racing team, and we run in a production series with a lot of restrictions on what we can do to the cars. This leads us to do a lot of "fun", "pretend race team' things, like DIY radio sets and cool suits and other such frippery.

One thing I would like to build is a series of connected timers/clocks, so that we can have a display inside each car that counts down the race (they're timed races generally).

The idea would be a screen in each car, as well as one in the pits, and a way to set a time and then start/stop them, all remotely. Obviously wifi is out as a) the tracks don't all have this and b)range, so I am assuming the signals would have to go via the cell network.

The use case would be the pit crew setting timers for things like countdown to race starts, formation laps etc, then resetting for race start, all remotely - perhaps from a mobile app. That part aside, would the Pi be an appropriate platform for the display/receiving parts within the car? I am not sure if there's a cellular module for the Pi, but am open to suggestions.

Just wondering what the thoughts of the experts here are on whether this is something I should/could be able to tackle, or whether I'm over-reaching.

How do I calculate audio dB/SPL level?

I want to calculate the SPL of an audio file that had been recorded and processed by my raspberry pi + cirrus logic audio card.

Is there anyway to go about doing this, preferably via python? I don't really know how to continue, as I had finished processing the audio file, but now I need to determine the amplitude/SPL of the file (other than viewing the frequency spectrum plot on audacity which doesn't really give an accurate/precise reading).

How to disable commandline over serial?

In a manual for an addon pcb to my RPi3, RaspBee, in the manual it say that I need to

disable commandline over serial:
$ sudo raspi-config,
Advanced Options - ?Serial - ?Disable Commandline over Serial

I don't have that in my raspi-config, I'm on the latest rasbian, jiessi
So I wonder how can I disable it now.. Disable Commandline over Serial
Syed Zain Nasir

I am Syed Zain Nasir, the founder of <a href=https://www.TheEngineeringProjects.com/>The Engineering Projects</a> (TEP). I am a programmer since 2009 before that I just search things, make small projects and now I am sharing my knowledge through this platform.I also work as a freelancer and did many projects related to programming and electrical circuitry. <a href=https://plus.google.com/+SyedZainNasir/>My Google Profile+</a>

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Syed Zain Nasir