Stablizing the standalone smartphone interface
- Goal of this project is to make 2nd Generation RSNAV Standalone Smartphone interface to work stable.
- The main cause of the problem is that 5v get exhausted when iPhone draws more than 0.5A from USB bus.
Required: Soldering kit, MP1584EN (12v to 5v) DC-DC step-down module, small heat shrink tubes, electric isolation tape, and soldering skill
DO NOT ATTEMPT THIS WHILE THE HARNESS IS CONNECTED TO ANY DEVICE OR VEHICLE COMPONENT. PLEASE, REMOVE THE HARNESS FROM THE VEHICLE COMPLETELY BEFORE YOU DO THIS. THERE IS A RISK OF ELECTROCUTION AND PROPERTY DAMAGE IF YOU WORK ON IT WHILE THE HARNESS IS CONNECTED TO THE HEAD-UNIT.
1. Identify lines and their function. All the other wires should remain as they are.
2. Add the DC-DC step-down module as seen in the following schematic. Basically, tab on 12V positive and system ground wires to supply electricity to the module, and rerouted USB 5v power from the connector to the output of the module, so that the module charges iPhone. After the completion, Pin 1, 2 is no longer connected to the RSNAV.
Note that 1,2 dotted lines are detached from RSNAV interface and rerouted to the module, but yellow 12v and ground black is still going into the interface.
3. This is the final product. Inspect and wrap it with electric isolation tape.