I have a few questions about a project I want to do

[G+_Alex Ford]

I have a few questions about a project I want to do.

 

I want to build a notification timer for the band at my church. I was thinking an arduino or pi with a led strip light. Plan is to make it green 10 minutes before stage time, switch to yellow at 5 minutes and start blinking red at 2.

 

The questions I have are:

 

How do I program it to do this every Sunday automatically? Cron job?

Can I set it to ping my NTP server on campus sunday mornings and get the right time?

Is it pretty simple to make it start blinking faster in the last two minutes?

 

 

I haven't really messed with these smaller computers so I am a newbie to this and would like some simple help on this part:

 

Looks to me in my research a arduino would probably be the best for this. Am I right in this thinking?

Should I power the lights with their own power supply?

What programming language is this stuff normally in?

 

 

Now for something that we might do if this works out well for the band:

 

I am thinking of making a “dB meter” that blinks the lights red if the green room gets too loud during the preaching part of the message. Would it be better to push this to separate device or get a pi 3 and have some computing overhead?

 

 

Thanks All!

[G+_Eddie Foy]

Neither the Pi nor the Arduino have a RTC (real time clock)  Both will need a RTC module to run stand alone.  The Pi, if connected to the LAN will automatically poll a NTP server for the time (remember to set your timezone) Saving the need for a RTC module on the Pi.

 

If the lights being are controlled are more then a small LED, you will need level shifting of some sort (mosfet, relay, triac, ssr, I/O module etc.)  How that is implemented hardware-wise would be basically if not exactly the same on both platforms.

 

For ease I'd opt for a Pi (LAN connected) running a cron job (python) to run the lights.

 

For efficiency and a bit more 'proper' the arduino or microcontroler would be it.

 

dB is another matter altogether. Its far from a linear scale.  But SparkFun probably has a breakout board.

 

Even a Pi 1 would be fine. it will be idling 99.5% of the time.

[G+_610GARAGE]

I think your best option would be a pi. Normally, I'm against using a pi for something like this, but you need time syncing, and db metering. The arduino could do that without a problem, but you need additional hardware to do so. A pi has everything you need onboard. Just connect it to the local network and it will automatically sync up to an npt server.

 

You should be able to monitor noise levels in a room with a microphone. I havn't looked into it, but I would be surprised if there wasn't some sort of bash script or command line utility out there that could read noise level through a microphone.

 

A cron job would be the easiest. Just have it execute a script at each interval to change the lights.

[G+_Fr. Robert Ballecer, SJ]

Arduino + RTC + Start/Stop buttons... Easy coding... I'll do a project. :)

[G+_Ben Reese]

I like the Pi idea too. Arduino with RTC would be fine too. Really, without an RTC might be ok if you don't mind syncing it every week or had a way of sending the time remotely. (As a proof of concept a couple months ago, I sent time from my Pi to an Arduino over NRF24L01+ wireless adapters).

 

Also, a $30 Android phone from Walmart would work too.

[G+_610GARAGE]

Ben Reese I like the phone idea. Controlling the lights might be more difficult though. You would need pins that can be controlled over usb or bluetooth.

[G+_Ben Reese]

Yeah, I just assumed the phone display would be enough.

 

I just see so many projects over complicated just to use something like a Pi. Don't get me wrong, the Pi is awesome and often the best route if for no other reason than educational purposes.

[G+_610GARAGE]

Ben Reese I didn't think of that. Yea, you could use a cheap tablet to(probably get one used off of ebay for cheap).

 

Yea, that actually a pet peeve for me. Using part for no other reason than its popular. There are many projects that and arduino would work better and there are many projects where a pi would work better. But there two different things for two different purposes.

[G+_Joel Belton]

Couldn't you just code using the internal 16mhz clock.. and code the lights for for increments of ticks.

[G+_610GARAGE]

Joel Belton While that is technically possible, it's not recommended. If he just wanted the lights to go on and off every few minutes, or go on after so many minutes of a button push, then that would be the way to go.

 

But he wants the lights to go on a specific time. The arduino's clock would wonder too much for that to be reliable. And if you loose power, you have to reset the clock.

 

RTC modules usually have a battery that can keep them powered for years. So you set the correct time once, and should be good to go.

[G+_Alex Ford]

Thanks for all the comments and ideas guys.

 

Ben Reese  and 610bob I thought of a phone also but if this works well I want to scale out to wrapping the rooms crown molding in LED strip lights. I feel a phone would not scale out that well. That and I want it to be simple/cheap to get going again if it fails.

 

I like the RTC idea and will research that more as 610bob is right and I want it to go off at certain time every sunday with out having to remember to hit a button. But, having said that a stop start button (like Fr. Robert Ballecer, SJ has in his comment) might work for other times we need a stage call. I will have to look into that also and see if I can have the button "reset" the timer.

[G+_610GARAGE]

Alex Ford Just an idea, if you go with a pi connected to the network, you could run an internal webpage from the pi to control the lighting. May be more complicated than what you're after, but it would be interesting.

[G+_Alex Ford]

All thanks agin and it looks like on Know how 222 Fr. Robert Ballecer, SJ  found just the device I needed for this project. I will order everything and see what I come up with.