iPhone controlled R/C car (UPDATED)

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(Originally posted on 5th of September 2008) It’s still not even a week since I bought a new iPhone 3G and during this time my brother and I did a lot of cool stuff. The iPhone with its accelerometer and multitouch display is ideal for making gadgets. When I got it home, we started thinking about some cool demos which we could make. Incidentally we found an old R/C car model 😉 Have you ever seen anything like this? I hadn’t 🙂 Did you ever think that an iPhone could do this? Enjoy!

Update (31st of July 2009)

Hack was very popular, biggest success is one chapter in iPhone Hacks book (O’reilly). It’s great experience and I want to say thanks to Damien Stolarz and Brian Jepson.

Many people asked me about source code, here it is. Documentation and howto are in iPhone Hacks book.

OS 3.0 for iPhone brings some new opportunities, including some bluetooth stuff. But unfortunatelly not SPP, so WIFI is still only chance to send something out from iPhone :-/

iPhone controlled R/C car from Josef Průša on Vimeo. Same video on YouTube.com . Controlling is very easy with the iPhone 3G. It has five buttons, four of them you can use for traditional „driving“ and when you press the last one, it unlocks the accelerometer control in the same way as in many driving games available on AppStore. Realization of this project did not take a long time, only one afternoon. Technically it is realized in a hell-bent way, but obviously it’s functional. Schematically: iPhone (OSCemote) → WiFi → PC → Max/Msp → Serial port → Arduino → Original controller. If you have some other cool ideas, leave it in comments. We can surely realize it 😉 .


OSCemote is application which sends data from iPhone to PC. It does it thru WIFI using OpenSoundControl protocol. You can buy it in AppStore ore try free lite version (unfortunately without accelerometer support 🙁 ) By the way, some big and complex audio softwares are compatible with OSC standard. For example, Traktor 3 by Native Instruments can sync tempo over OSC. You can download test patch here. For functionality you have to download Max 5 runtime.


On PC connected to network is running Max patch, which catches data from iPhone, converts it into simpler form and send it thru serial port to Arduino.

Max/Msp is generally used for audiovisual instalations, but also can do crazy things like this project 😉 .


Arduino is simple development kit with
microprocessor. Arduino process data from Max and next simulate switching on
real R/C controller using transistors.


iPhone2Midi – control your software with iPhone finally clever

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Few moths ago my brother and I’ve made iPhone controlled R/C car. It starts my thinking about real usage. First attempt was this video on youtube. I’m very busy these days but I’ve found some time to make something more complex.


It’s basically PC part for OSCemote.

OSCemote is iPhone application available on Appstore. Costs few $.

It’s Max/Map patch, so you have to install last Max/Map runtime.


Philosophy is to have everything under your control.


First row is managing multitouch pad. Each button represents one pair of MIDI CCs. If is button toggled, program starts to send midi. Every button even has his own midi note, so you can map it better. For example: if you toggle button 1, it’s turn on effects and MIDI CCs changes effects parameters.


Second row is for accelerometer. Same as multitouch. Every button represents three MIDI CCs and one MIDI note.

Third and fourth row is only buttons. Every button represents one MIDI note.

You can set type of each button. Hold – you have to hold button, if you release it, it sends Note of and switch off the MIDI CCs. Toggle – first press activate the button and second press deactivate it.

You can set amount of multitouch pad and accelerometer by setting red
sliders on sides.

Reading and writing presets

You can save your settings of button types, MIDI CCs and notes by pressing
Write button in settings section.



Only unzip and run  “iPhoneMidi.maxpat”


If you have some ideas to improve it, write it down to comments or send it to my email [email protected]



USB iPhone battery pack from MSI Wind battery

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It’s a long time ago since I’ve bought MSI Wind netbook. I’m not using it very much, because I’ve bought new MacBook, but it doesn’t mater. have two batteries for Wind, one small original 3-cell and one extra large, extra cheap 9-cell from eBay. The smaller one isn’t used too much, because it can power netbook only for 2 hours (bigger one 6 and more 🙂 ) . I’m very curious and I have Monome 128 and I hate it’s big ugly 12V power adapter, battery can be good choice, so I decided to open it. Spoiler: Battery remains usable even in netbook!! Video and howto after break!! If you like this idea, send link to this article to your favorite notebook manufacturer, maybe we can change actual state!!



– USB female connector TYPE A (Sparkfun $1.25)

– Volatage regulator 7805 (Sparkfun $1.25) or fancier and cooler 78SR Step-Down (Digikey $14.01) (thanks to Max via comments)

– wires, soldering station, hot glue etc. 🙂

About & Howto

Opening of the battery case id pretty tough, I had to use even a knife 🙂 There is a lot of ICs in battery, more than I thought, but finding source of 12V power was pretty easy. Battery has even a lot of free space, good for us 🙂

Because of lots of space, I decided to add USB charging capability (for iPhone etc.) At first, I had to decide where is the right place for connectors and cut the holes for them. Three pin connector is 12V supply (scheme is +-+, so you can’t plug it wrong way 😉 ).


I found source of 12V and solder cabels on it. 5V for usb is regulated by 7805 from 12V.

7805 regulator was pretty hot, iPhone wants 500mA 🙂 We added small passive cooler, but it wasn’t as efficient as we thought. After pluging iPhone, temperature rised up to 120′C 😀 We had to do better cooling = bigger passive. Second try cools it on 70′C. Good job!


Battery had holes in case, but they was covered by stickers. We decided to cut the sticker off for better cooling.

One more thing, close the case and it’s DONE!!! Looks like new 🙂

Full charge of iPhone 3G tooks 2hours and 22minutes. I did graph of charging so you can compare it with charging from PC Wind baterry iPhone Charge Graph 😉 After full charge of iPhone still remains 50% of juice in Winds battery!! So you can charge twice 🙂 But I think it can be even better, if you do a more efficient PCB, 7805 wich we used has lots of temperature losts 🙁

Battery can power up Monome 128, which was original idea of hack 🙂…