Even if we like it or not, we have been in the position where we sit in a car for hours on long journeys. To pass the time, you take out our your phone but sooner or later you get the stupid message from the mobile company saying you run out of data, and then you begin to miss your Home WiFi.
Step 1: Checking the Power Output From the Car
Eventhough most vehicles use a 12 Volt battery to start it up and to power the various electronic items operating inside it, the voltage does not stay constant due to various reasons such as the power draw from the Lights and also the power supplied by the vehicle alternator.
Using a voltmeter we can check the voltage supplied by the vehicle cigarette lighter port, which is the readily available port to supply power for accessories.
The car I tested out with gives out 14 Volts through its cigarette lighter port. This is too high for most WiFi routers since most of them run on 12 Volts. There are some which also run on 5 Volts so you should check the specifications beforehand.
It is fine to go under voltage, but not over voltage. We need a voltage regulator which keeps it constant at 12 Volts if the source goes above 12V.
Step 2: Building the Voltage Regulator
List of necessary items:
1. 7812 Voltage Regulator
2. 2 x 10uf Capacitors
3. Copper Stripboard
4. Heatsink for the Regulator along with a bolt
5. Car Cigarette Lighter Plug
6. 12V Male Connector Jack
7. DC Wire
8. Housing or an old casing
These few items are available even locally and fairly inexpensive to purchase. We will use the copper stripboard to mount the 7812 voltage regulator, the 10uf capacitors and the heatsink. The heatsink is essential to keep the voltage regulator cool as it tends to heat up a bit (it wont get burning hot). The 7812 voltage regulator can be firmly held to the heatsink with the use of a bolt. If you get stuck with the connections, you can refer to the circuit diagram.
After the components are soldered in, the input and output wires can be soldered.
Step 3: Wiring the Cigarette Lighter Plug
Cigarette Lighter Plugs do not come wired right out of the box, so you need to get the soldering iron out again. You can refer to the diagram for polarity when soldering in the wires to the Plug.
Step 4: Testing Out the Voltage Regulator
Finally we need to check the voltage from the regulator to ensure it is around the recommended standard. If its below 12.5 Volts, it is good to go.
Run a speed test to add traffic onto the router to test if enough power is supplied to it and that it does not restart. If the router restarts, that means it isnt receiving enough amps. Luckily most WiFi routers consume 1.5 Amps or less.
Step 5: Check Out the Video for a Better Demonstration
We have also put together a video to demonstrate this procedure more clearly.