What happens to old smart phones?   Can you trade them in?  Sell them? Rick Broida at c|net has some better ideas:

1. Keep it as a backup phone

The straits would be less dire, though, if I could just grab my old standby. I’d still have access to my calendar, contacts, email and the like (because they’re all synced), along with daily-use apps like Facebook, Spotify, Twitter, my password manager and so on. There’s really no better short-term rescue option.

In fact, if you still have your new phone (assuming it’s merely busted and not lost or stolen), you can probably just pop the SIM card out and back into the old phone, restoring voice and data until repairs are made.

Of course, you don’t have to stick the old phone in a drawer and leave it there in case of disaster; you can also keep it as a low- or even no-cost second line. For example, if it’s an unlocked GSM model, grab a SIM card from Freedompop (about $13, or AU$17, £10) and sign up for the Basic plan. It affords you 200 voice minutes, 500 text messages and 200MB of 4G data per month — at no charge.

For more on this idea, check out my post on how to set up a backup phone.

2. Use it as a dedicated camcorder

Whatever you’re recording — a wedding, a kid’s soccer game, a music video or your sure-to-win-the-film-fest indie movie — nothing beats multiple cameras. When it comes time to edit, you can mix footage from different angles and positions to create much more interesting video.

Needless to say, your old Android can make a great second camera. Even older, lower-end phones can usually capture at least 1,920×1,080-pixel video at 30 frames per second. Clear out as much storage as possible to make room for new footage and you’re good to go.

3. Use it as a baby monitor

All you need is an app like Dormi, which is designed expressly for this purpose. In addition to both audio and video monitoring, the app offers two-way audio so you can talk to (and hopefully soothe) a crying baby from afar.

Speaking of afar, you can tap into the audio/video feeds from just about anywhere, provided the Android phone is connected via Wi-Fi. Dormi also supports multiple “parent” devices to the phone that’s doing the monitoring. The app is free but limits you to four hours per month of monitoring. To unlock lifetime monitoring, there’s a one-time fee of $9 (AU$11.89, £7).

4. Use it as a video doorbell

No baby? Consider putting your Android on door duty instead. No, the phone itself doesn’t go outside; you’ll need to install either an outdoor Wi-Fi webcam or a smart doorbell. Then your phone can serve as a full-time video monitor, one that lives on, say, a coffee table or nightstand.

For example, the Canary Flex is a versatile, security-minded webcam that can go just about anywhere — including outside. Alternately, check out video doorbells like the August Doorbell Cam, DoorBird Video Door Station, Ring Video Doorbell and SkyBell Video Doorbell.

5. Give it the GoPro treatment

Whatever mount option you end up with, hit up Ebay for a cheap Bluetooth camera-shutter button. (They’re available for as little as a few dollars.) That way you can start and stop video recording without having to fiddle with the phone while it’s mounted.

6. Create a dedicated VR headset Get ready for a surprise. That old Android phone of yours? Virtual reality powerhouse! It’s true: A smartphone can serve up some terrific VR experiences. All you need is a headset and some apps.

Even more surprising: a headset won’t cost you much. Amazon, for example, offers dozens of universally compatible VR goggles priced in the $20-to-$35 range (AU$26-AU$46, £15-£27). Look for a model that lets you adjust focal width and length, the better to accommodate users with less-than-perfect vision. I also recommend choosing one that comes with a Bluetooth gamepad, the better to control games and access menus.

As for the apps, hit the Google Play Store and search for “VR” or “Google Cardboard.” Both will reveal a wealth of games and other experiences that are compatible with nearly any Android and VR headset.

7. Leave it on your nightstand

Alarm clock: Not ready to roll out of bed yet, but don’t want to fumble for your phone to turn off the alarm? Check out Voice Snooze Alarm, which is exactly what it sounds like: An alarm clock you can snooze with a customizable vocal command. (Come on, you know you’ve always wanted to tell your alarm to “Shut the **** up!” Now you can.)

Clock radio: TuneIn Radio is a good choice, as it has both alarm and sleep-timer features.

Dedicated e-reader: iBooks, Kindle, Nook, OverDrive — you don’t have to limit yourself to just a single app.

Meditation player: I’m partial to Calm, but there are a zillion others.

Spare Roku remote: Check out the latest update.

White-noise machine: I don’t have a particular favorite; hit up the app store for lots of choices.