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Will this work for my car?

Posted: Mon Jul 07, 2014 8:06 pm
by deceased10
Hello I am new to this and am looking for as much information as I can get before I buy anything. I will try to explain as best as I can what I am trying to accomplish and you guys can tell me if this board is the one I'd need or not.

Here is what I am trying to do:

Currently in my car I have about 8 switches controlling different led circuits. It's really messy and I'm looking to get rid of these switches so my car will look cleaner/Nicer. After research I've come to the conclusion that an arduino would work perfectly for this. The only problem is I know very little about them and I noticed that there are plenty to choose from. One of my main questions is what would be the best board to get. My plan is to have all these circuits be controlled by my ANDROID cell phone. Now I watched the superhouse videos and he uses internet to control his lights etc.. Well I wont have access to internet in my car so another question is if I have my phone connected to the arduino somehow can I send on and off commands to it? Or can bluethooth do that as well? What I would love to do is create an android app that has nice buttons that can control it is that possible?

Next from what I've read I will need a relay board to control these cuircuits? How does the relay board get connected to the board. I need about 8 different channels to control. I have nothing that draws allot of current, just led circuit's and door locks. Any information would be great or even a list of the parts I'd need. Also can I just hardwire the arduino to my 12v car power? or does the arduino run on a different voltage?

Re: Will this work for my car?

Posted: Mon Jul 07, 2014 10:16 pm
by cef
You could use the USBDroid if you're happy connecting to it via a USB cable. I haven't seen it work using Bluetooth myself (someone else may know).

As long as you've got a fairly recent version of Android on it, it should work. You would either need to write your own code on the phone, or use one of the many app systems out there (such as Handbag), which basically display stuff on the phone for you from within the Arduino sketch. I think Handbag also requires direct USB connection, rather than Bluetooth, but worth checking as that may have changed.

Handbag for Android:

For controlling the circuits, you could use the Relay8 shield. If it's really low current, you can drive them directly out of the shield, otherwise you'll need to drive them using a relay attached to the shield (anything that uses more than 110mA).

You should be able to run the Arduino and the Relay8 off the 12V in the car, but be aware that the car power tends to be quite variable. You might want to put a few diodes and a large cap between the power and the Arduino to provide a bit of protection. The DC jack on the Arduino (and the DC input on the Relay8) will run down to anything as low as 7V, so adding a diode or two won't cause the Arduino a problem.


Code: Select all

+12V IN --->|---+--->|--- OUT to Arduino
I'd suggest standard diodes like 1N4004's and a largish cap like 2200uF or bigger, just to be on the safe side. You can add inductors (or replace the second diode on the right with an inductor) and all sorts of other things, but diodes stop the current flowing backward and just avoid all sorts of little issues such as resets due to ignition noise. You can however buy professional filters that will do much the same thing if you prefer a pre-built solution.

PS: There's all sorts of ways to tackle that. This one is simple to do, fairly effective and cheap, which is why I suggest it.

PPS: Please excuse the poor-mans text-drawn diagram.

Re: Will this work for my car?

Posted: Tue Jul 08, 2014 1:10 am
by deceased10
Thank you for the quick and detailed information that you have given me! I appreciate it and it definitely helps. As for the bluethooth I knew that the board itself does not provide bluethooth but I do know that there is bluethooth modules for the arduino that can be atached such as ... 7tD8vldV8E

would that make my board compatible? I do like how this USBDROID offers charging to the phone as my original plan is to have a tablet molded and hard wired into the car. This makes it that much easier to do! It seems Like I got a good grasp of what I am getting into and what I would need. This board does seem like a good solution, and this does work with the USBDROID correct? ... 7tEc_ldV8E

So it seems like I will need

8relay shield
8 chanell relay bar

and then custom code to make my own app. So plugging my phone into the arduino allows me to send commands via the cord correct?

Re: Will this work for my car?

Posted: Fri Jul 11, 2014 12:31 am
by cef
Yes, plugging the Android device into the USB HOST port in the USBDroid is how the commands are communicated.

As for Bluetooth, you could possibly do that by writing both the Android side and the Arduino side to do the communication. Note however it most likely won't be a simple job, and if you're not experienced in Arduino and/or Android development, it could take a very long time. Starting with a USBDroid, communicating over the cable, and using something like Handbag on the Android will definitely reduce the amount of development on both sides while getting you a reasonable solution to your problem.

Once you get something you're happy with, you could always improve the design later by adding more features or by writing your own Android/Arduino app pair that communicate over bluetooth and/or cable.