Your old Android phone makes a great dash cam because it can do a lot more than just record the road.
A dash cam is a really cool thing to have. You never know when you'll see something worth recording on the road until it's too late (never whip out your phone for a photo while driving!) and sometimes you need to document what happened in case of an accident or another traffic incident. Someone you know probably has a dash cam and is glad they had it at least once.
Dash cams are also pretty cheap nowadays, but they are also pretty basic. If you're going to have something attached to your windshield, why not use something that can do so much more than "just" record the road? Your old Android phone can make for a great dash cam, and if you want to put a SIM card in it or tether to your current phone, it can become a standalone GPS unit or music player, too. Beats sending it to the recycle center, right?
Here's what you'll need and how to go about doing it.
You'll need your old phone, of course. But you'll also need a few cheap accessories to get it in place and keep it running.
You'll need a car charger and cable long enough to reach. You don't need anything fancy here because you won't be trying to quick charge anything or worry about supplying a lot of power. An $8 Amazon Basics USB car charger and a long charging cable like this 15-foot model for $8 is fine. Just make sure you use the right cable for your phone — USB-C cables will be a little more expensive.
You'll also need a good dash mount. That doesn't mean the prettiest one; it means the one that will hold your phone in place with the camera lens uncovered without obstructing your view of the road. On that note, be sure to check any local laws about sticking anything to your windshield because the local police will know those laws and tickets are expensive. Everyone loves the $25 iOttie One touch Dashboard & Windshield mount and my wife swears by the $10 INCART Rearview Mirror Phone Holder. Make sure you buy something that will fit your phone and allow the camera lens to see the road and you're set.
Next you need some software. Google Play is chock full of apps that can act as a dash recorder, but most everyone loves AutoBoy Dash Cam and Black Box. It's filled with features that will remind you why a phone makes for a better dash cam that one you can buy. You'll find features like auto-start and stop, GPS tracking, and more in AutoBoy, and best of all it's free. There are plenty of others, though, and you might want to try them all and see if you like another better. If you do, let me know, please!
This is all easy to figure out how to use. Put the mount in place, put your phone in it, and run the cord so it won't get tangled up in anything while you're trying to drive. These little stick-on cable clips can be a lifesaver for that. Make everything nice an neat, but be sure you're able to take the phone out of its mount easily and you're good to go.
Don't forget it's there
The biggest downside to any dash cam also apply when using a phone — people will steal it and the sun can ruin it.
Phones, locked cars, and hot sunlight don't mix.
Never leave a phone in a mount right on the windshield for passing thieves to see because that will lead to broken windows and stolen stuff. Just because a phone is old to you and makes for a good dash cam doesn't mean it's not going to be a nice prize for people who steal things out of cars. Unfortunately, those people do exist.
And it's never a good idea to leave any sensitive electronics inside a hot vehicle exposed to the sun. Especially ones with a lithium battery inside. Either use a windshield shade or pull it out of the mount and toss it in the glove box (or carry it with you) to mitigate both of these issues.
Most of all, be safe. Anytime you mix a gadget with a car there is an urge to start messing with stuff. Don't do it! That's the whole purpose of using a specialized app for this instead of just using your phone's built-in camera app, and while we hope you never need to document anything for your insurance company, we especially don't want it to happen because you couldn't resist touching stuff. Be smart and have fun!