While there's some debate over who invented the telephone, it has been nothing short of a game-changer to the human race. It has evolved in leaps and bounds, transforming into what we all know as the smartphone today. And it’s expected to get even better as tech steadily advances. But before then, we are all stuck to constantly recharging our smartphones until some genius innovates a charge-free phone.

So, what are you to do when your phone is rapidly running out of juice, and you have no access to a charger? Try making any of these seven lifesaver DIY phone chargers below.

1. USB iPhone iPod Dynamo Charger

Screen grab of USB Iphone/Ipod Dynamo Charger

You don’t need to be an avid cyclist to use a dynamo charger. This project lets you transform one into a powerful charger you can carry on the fly. It’s small, portable, and the cherry on top of the cake: it can efficiently recharge your iPhone and your iPod, and other smart devices in your arsenal. The best bit? It’s only a two-wire connection, meaning you won’t need any circuitry expertise to put it together. Check out the detailed Instructables guide to get started.

2. Solar iPod/iPhone Charger

Screen grab of How to Make a Solar IPod iPhone Charger

This solar charger charges your iPhone not just via solar but also via USB or wall wart. And it’s powerful enough to recharge an iPhone, iPod, or any other smart device you may own.

You can rely on it whether you are hiking off-grid without access to power, stuck at an airport due to late flights, or even in the comfort of your home. Simply plug in the solar cell and then connect it to your iPhone when you have no access to power, and set it aside for the USB charging function when back to civilization. Check out the step-by-step Instructables guide to build it.

If you’re building this project because you frequently go off grid, you should build one of these cell phone signal boosters to be self-sufficient.

3. Solar Altoids iPhone/iPod Charger

Screen grab of Solar Altoids IPhone/ IPod Charger

Altoids are popular for not just being the curiously strong mints we’ve loved since the 19th century but also for the iconic metal tins they come in. The tins are compact yet hollow enough to accommodate small accessories like earphones. With a little creativity, you can transform them into anything, including a lifesaving, solar-powered iPhone charger. It is affordable, takes about an hour to complete, and makes an excellent accessory, especially if you are always off-grid and need a reliable way to keep your iPhone powered.

You’ll need a charging circuit, an AA battery holder, a pair of rechargeable batteries, and all the components listed in the easy-to-follow Instructables guide, to build this handy solar DIY phone charger from an Altoids tin. If you successfully build this project, you will definitely like to try out some DIY phone charging station ideas.

4. Simple USB Socket Charger

Have you recently lost or misplaced your Apple adapter and don’t want to spend some 30 bucks or more on one? If so, you’ll be happy to know that you can—with a 5V wall adapter, breadboard, a couple of pin headers, resistors (one 10kΩ and two 100kΩ), jumper wires, and an indicator LED—make a fully-functional wall adapter and save the cash, as shown in the Instructables guide.

Before analyzing related costs, note that most of the supplies needed for this project are readily available. You may even recycle them from unused or old electronics. For instance, instead of buying, consider upcycling a 5V wall adapter from your first ever cellphone charger and chop off a USB connector from one of the USB cables sitting idle in your old electronics stash. To match your creative phone charger, why not transform your phone case with these cool DIY ideas?

5. USB iPhone/iPod Charger in a Tin

If you found the Altoids tin charger highlighted earlier fascinating, you’ll probably love this version even better. It is compact, and all components—from a voltage regulator, batteries, and resistors, to connected wires—are all securely held inside the tin. Hence, the only parts exposed are the USB port, switch, and LED to indicate when it’s on or off.

It undoubtedly takes the bag for being utterly compact, and its 2V output means it’s capable of recharging an iPhone or iPod. While the circuit is a bit technical, the Instructables guide does a pretty good job at breaking it down so even the non-tech savvy DIYer can give it a shot.

6. Use Wasted Heat to Charge Cell Phones

This DIY project might be quite technical, but it lets you convert heat that would have otherwise been wasted and released to Mother Nature into electrical power, potent enough to recharge your smartphone. It lets you take two birds with one stone: save nature from additional waste, and money on a new charger. A thermoelectric unit is the heart of the project but, as highlighted in the step-by-step Instructables guide, you’ll also need a heat sink, thermal paste, regulator, capacitors, and a female USB plug to make one.

7. Solar Powered USB Charger

Screen grab of Solar Powered USB Charger

Are you looking to go green? You can always start small by switching from an electric-powered phone charger to this solar-powered USB charger. Although we’ve got others on our list, this DIY phone charger stands out because it directly generates its power from a series of solar panels.

It sounds complicated but, as shown in the easy-to-follow Instructables guide, it’s one of the simplest lifesaver DIY phone chargers you can build on our list. You only need to connect positive and negative solar panels, connect your wires to a regulator, solder, and glue it all together, and boom! You have an efficient, fully-functional solar-powered phone charger at nearly a quarter the cost of buying a commercial solar charger. You can also go green by using your old phones to build these awesome DIY projects.

Build a DIY Charger, Save Money, and Go Green

Smartphones are great, but being stuck with a dying one and no access to a phone charger is incredibly frustrating. Luckily, you don’t have to bear with the situation as you can always build one from scratch using the ideas above or by borrowing some concepts to come up with an original, never-seen-before DIY charger version.

Note that most of the lifesaver DIY phone chargers above are meant for iPhones and iPods, but you can always tweak them a little to enable Android compatibility. Even better, they all maximize alternative energy sources such as solar and wasted heat to generate power for your iPhone, meaning you get to skip the costs of buying a new charger and reduce your carbon footprint.