Do you remember my post about a R/C USB adapter ? Today, I tried a Redpark TTL cable for iPhone.

Starting with the R/C USB adapter, I did not changed anything on the Arduino side. I only ported the Processing code on iOS, and connected the Redpark cable to the Arduino. That’s it ! I can now check the output of my R/C receivers on the ground only with my iPhone, an Arduino, and the cable.

You can see the result in the following video :

On the hardware side, the only thing to take care is the voltage used on the serial connection between the Redpark cable and the Arduino. The cable (and the iPhone) uses a 3.3V logic, whereas the Arduino uses a 5V one. Connecting cable TX directly to Arduino RX is OK as Arduino can handle a 3.3V input, but connecting cable RX directly to Arduino TX will damage your cable and maybe your iPhone. You have to make a level-shifter. Best solutions uses transistor or zener diode, but two resistors in voltage-diviser do the job.

For the iPhone app, using the Redpark cable is quite easy, thanks to its SDK. It totally masks the EAAccessory framework. It’s very handy for prototyping using the iPhone dock connector without a MFi access, but you will not learn the EAAccessory framework.

To release it on the AppStore, I need your support in order to subscribe the Apple Developer Program.