DIY Project, Wireless Remote, How to Acquire Power When Car Is Off?

12Volt Members, I'm going to add a project to an older car that is basically a DIY similar to some of the remote control systems from alarm companies. It's a 1999 Ford Taurus, so while it's got OBD-II, it's not CAN-Bus. The wiring info for my car is here: https://www.the12volt.com/installbay/alarmdetail/926.html First part will be adding wireless controls for: - door lock (which, from what I can tell, also arms the factory alarm) - door unlock - windows up - windows down - Approach & interior lights (1 circuit) - Horn - Door trigger (activate alarm) - Deactivate Factory alarm The relays can be switched from momentary to locking from the remote at any time. I know I'd have to set them to momentary and hold them for a second or two to move the windows up or down. Q: How would I get power to move the windows while the car is off? Will I need to run a hot wire to the relay(s) to power the windows? I would assume a diode is necessary to prevent that hot wire from overloading anything when the car is running, or I could also run a NO relay on that hot wire that closes when the car is turned off. I'd like to add more, but not sure yet. The relays are rated at 10A. For the project, I don't have an option to use higher amperage relays. I don't believe that any single window reaches 10A. The fuse that protects the power windows, power moon roof, map lights and dome/door light, and more, is 10A. I can close all of the windows with all of the lights on without any problem (mine is not equipped with an opening roof). I've connected an ammeter and moved all 4 windows and it didn't hit 10A. I know that could be different if I was putting all of them up and they were at the top. Q: I don't think I'm going this route, but, I figure I'll ask now just in case. In the event that I want to lower the possibility of using more power through the relays than I should, has anyone done or seen where 1 relay (mine rated 10A) controls 2 other relays (front windows, rear windows)? If so, I'm guessing the output from the 1st relay would be fed in parallel to the next relays. Sound correct? The setup is also going to use an Android tablet (it too will have control of these circuits) with a wired back up camera via the USB on the tablet. (I know that's more 5V stuff than 12V stuff). Webpager - Upfitter, computer guy, car guy. I can't tell the difference between Columbian or African coffee, but I knew at age 4 the difference between volts, watts and ohms.

This is a pretty ambitious project. I hope you have a lot of spare time available. For your window rollup and roll down your best bet is to purchase 2 window control modules. If you shop around you will find them for about $20 each. Is this a passive keyless entry system that you are adding? Have you tested the backup camera interface and software on your Android? I have done this, so could give you advice if you need it.

I've been putting the plans together for a while, but need a few answers. Agreed, I see it as ambitious, but not overly. Yeah, I've got too much time to spare. The wireless relay array is readily available off the shelf. It's controlled via wifi or bluetooth, or a proprietary system like a car remote. I plan to use wifi. I can control it from my phone, or I can call the tablet and have it access the functions. It seems most of the connections are in the driver's door, except for 2 or three that I want right now. I was thinking again about more items, and if I'm going to have a deactivate factory alarm wire, that I believe will trigger the interior light circuit, so I'll have perimeter lights. The locks, horn, arming, and disarming would all be easy, momentary switches. The backup camera seems to work without an issue. I just need to fabricate a mount for the camera. I have not committed, but I believe I will switch the hinges on the center console armrest so that it flips to the front. The tablet will be mounted on the underside of the armrest so it'll be viewed when I flip the armrest forward. I'll feed the camera through the car, under the seat, and up to a USB hub. The USB wire that comes from the camera I've pulled apart, and added a relay to the +5V wire. It will close the relay with the backup light circuit. That will give the camera power which triggers the software to override the screen. I got this idea from Youtube, BTW. I want to find a way to have the camera software load at power up, but I'm not really worried about it since the tab runs for about 2 days on standby. The camera triggers the software and comes up in about 1-1.5 seconds. I am also using a hub as I want to use the tablet for some of the entertainment and GPS functions in the car. I'm certainly open to advice. I'm using a wired camera as the wireless is just too slow to connect. Suggestions? I have thought about window control modules, and will likely go that route, but I was thinking just momentary switches so I could roll the windows up or down partially (guessing at position if I can't see the car of course). With no sunroof, I'm guessing two 4 place controllers, 1 for up, 1 for down. I remember one of them had a venting option on the roll down. Anyone remember which controller that was? It's a lot, but it's almost all wiring and labor. The relay array is about $60. Diodes are cheap, additional relays are inexpensive; the long USB wire, a hub, a couple more USB cables and adapters (USB to Micro USB) I grabbed from an e-waste recycle place for $1 each/bag (a DOLLAR for a 24 foot USB cable!). If I go with window modules, that's about another $40-$70. Passive keyless entry? I was thinking about adding a bluetooth relay to my locks. If I'm close enough, it'll unlock the car (and enable the ignition). If I'm out of range, it'll lock the locks and disable the ignition. I'd have the tablet tied to the ignition cutoff as well. If I don't have my phone/no charge, etc, I can open the doors with a key or the factory fob, and close the relay for the ignition via the tablet. I'm open to suggestions and further ideas. I know the site and forum is more for commercial parts and issues, but the knowledge base here can't be beat. Thanks, MarcWebpager - Upfitter, computer guy, car guy. I can't tell the difference between Columbian or African coffee, but I knew at age 4 the difference between volts, watts and ohms.

You are on the right track with the backup camera. A camera with composite video output can be coupled to a Easycap device (using UTV007 chip). EasyCap Recorder Pro works fine. Use Tasker (if necessary) to start your apps on device boot. I am using a capacitive password entry keypad to unlock my vehicle if I forget/lose my fob. The keypad is adhered to the inside of the windshield. I assume you will be pulling your tablet out of the vehicle and charging it at home. If you are contemplating charging the tablet's NIMH batteries while it is the vehicle you should be aware that the batteries won't like the high ambient temperatures (or freezing for that matter) that they will be seeing in the vehicle. I have pulled the batteries out of my in-dash tablet based on experience in harsh northern winters (which you may not be worried about). Have fun with this.

I'll check out Tasker. I downloaded and installed Car DashDroid today. I'm liking the look. Right now I've got USB Cammer (Camera?) and it looks ok. Since it won't be connected to internet all the time, I'm guessing the ads from the free versions will be minimal. I don't need the keypad for this car, but tell me more about it. Is it Arduino? Something self contained (save for the connection to the locks)? Off the shelf? This car is a 99 Taurus and has the driver's door keypad. I was able to access the code with a program called FORScan and an ELM327 device. I don't know if I'll use Torque Pro or the Android version of FORScan, but it gives me a lot of monitoring, all customizable, from sensor data to using the sensors in the tablet to do a 0-60 time (or set the MPH from and to and it'll measure). A friend, though, might have good use for the capacitive keypad. Not sure about charging it at home. If I stay put, the weather might get to 35 at the very coldest, and 90 at the very hottest. If it's forecasted for cold winter nights or during hot summer days, I'll probably pull it out. If I move (New England) I'll likely pull it out often from temperature as well as humidity. Thanks. I am having fun so far. Doing a few other things with it as well.Webpager - Upfitter, computer guy, car guy. I can't tell the difference between Columbian or African coffee, but I knew at age 4 the difference between volts, watts and ohms.

This is what the keypad on the inside surface of the windshield looks like. It needs to be interfaced to a microcontroller (not necessarily an Arduino).