Mini RC Car - Part 5 (final)

After weeks of 'other things', here is the 5^th and final post on the Mini RC Car project.

It's alive!!!

This final configuration works on a single 9v battery. Yes only one power supply because I found the real source of the noise problem coming from the DC motor. Like any good bug it was a code 12 since I assumed that the motor had a capacitor on it... NOT!  Here you can "see" the result.

Parts:

1x racetrack toy car

1x micro servo

1x 9v battery

1x 5v power regulator

1x pn2222 transistor

1x 1N4001 rectifier diode

4x ceramic 0.1uf capacitors

1x 16MHz crystal

1x 28 pin socket

1x 4 pins female headers

1x 3 pins male headers

1 9v snap connector

1 Atmega328

1 BlueSmirf bluetooth breakout board

1 PCB
1 Wires

scrap metal/wood for structure

Tools:

Dremel

Soldering iron

Hot glue gun

Arduino board (e.g. UNO) for programming the chip

Android device with bluetooth

For the maniacs out there I'll probably add this on Instructables where I'll go over all the geeky details.

To view the whole project go here.

Thanks for reading.

Mini RC Car - Part 4

Back on track with 5v...continuing the Mini RC Car build.

So I couldn't wait on my 3.3v voltage regulator.  I decided to switch the car to 5v and use a good old 9v battery.  This is what it looked like when I tested the new power system:

This has to be the ugliest RC car ever made.

After getting over the look of the beast, I now have to do the following:

• Test the servo
• Clean up the electronics (there is still some quick prototyping part or assembly)
• Make a more permanent stack assembly for the battery, power regulator and circuit board.
• Programme the Arduino and the Android phone (remote)

This shouldn't be too long.  Here's the car running a test with the new power system:

To view the whole project, go here

Mini RC Car - Part 3

A few bumps in the road...continuing the Mini RC Car build.

First I decided to get rid of the variable voltage regulator.  It was causing all kinds of problems mostly because I'm using a 3.7v power source.  Anyway the Arduino runs fine for now and I have some 3.3v regulators coming through mail pretty soon.

A glitch never comes alone but I'm lucky since the next problem was simple. The DC motor is creating noise feedbacks that are confusing the servo.  That one is an easy fix by adding a 0.1uf capacitor on the motor.

The third one is a show stopper. Or maybe I should say 'a show slower'.  The cellphone battery I'm using is not strong enough for this whole operation.  It's a 3.7v 850ma LiPo cell.  I have to power the Arduino, the BlueSmirf Bluetooth board, the servo and the DC motor which is done using a transistor.  I guess I should have done some calculations first.

Soooo, I'll get to that and I'll order the right battery.  Until then, PAUSE on this project.   Mmmmm, that gives me an opportunity to start another thing.  Muha ha ha ha ha

To view the whole project, go here

Mini RC Car - Part 2

...continuing the Mini RC Car build.

To attach the steering servo, I drilled holes in the frame and bolted the two together.

I then hot-glued the front frame to the rear half, making sure I had enough ground clearance and all 4 tires on the ground.

The next step was creating a board that would support the Arduino chip, a socket for the bluetooth breakout board, the 3.3v voltage regulator and a socket for the servo connector.  Here's the prototype:

After a bit of soldering, here what I have so far:

Now that I have all the main components, I'll do the final assembly and start programming the on-board Arduino code and the Android controller app.

To view the whole project, go here

Mini RC Car - Part 1

While cleaning up the basement, we came up on that old electric racetrack and finally decided to get rid of that thing.  Of course I kept all the electrical circuitry and the kids kept the cars to play with.

Since I needed another project to start to justify not working on all the important stuff, I decide to re-purpose one of those car into a mini RC car that I would control using my Android phone. Communication will be done through bluethooth which I tested earlier.

My first test was to control the motor using an ATtiny13 Micro-controller.  This chip uses the same code as Arduino but has only 8 pins.  I powered the assembly using a LiPo battery from a dead cellphone.

I started by cutting the frame in two and hot glued a micro servo on the front part.

I then used a PC card slot-cover and bended it into a frame that would join the two half.

To view the whole project, go here

Trans-App / a bleep on the radar

A Facebook phone build on a mix of Android software & hardware optimize for Facebook-type features. Could this be the first real Trans-Application device? Like I mention in this original Trans-App post, the idea that devices would have to adapt to applications needs could become a reality.

To clarify the concept of Trans-Application I should say that Trans-App devices must be designed around constraints dictated by two or more applications. If this new Android-Facebook phone supports more than Facebook, it's well on its way to be a Trans-App device.

Why is this important? Because nobody will want to carry a Facebook phone and a LinkedIn phone and a Google Wallet phone. We want things to be integrated into one device. And while we're at it we want that device to fit in our pocket and have an 8 inch screen and.. um.. you know what I mean 'cause you want it too.

Purchase may soon be driven by the preference of devices optimizing the user experience of the favorite applications. Not by the OS. Not by the Browser. Not by the hardware brand.

Sunday night with Bluetooth

What do you do after installing your Christmas lights? Build a robot of course!


This projects started with a modified version of the Boe-Bot on which I added big dirt wheels scavenged from a dead RC car. The simple structure on top is made with my usual LEGO spider-legs system supporting the Arduino and its proto shield. I'm using the Sparfun proto shield since it has a build-in connector for the BlueSmirf Bluetooth breakout board and.. it's red. I also use two power supplies to separate the servos from the rest of the electronics.

Software wise, I used the Sena BTerm app to do some direct communication with the Bluetooth device. This app was very practical since it enabled me to only code on the Arduino side. This made prototyping very fast. The only real work began when I had to make the real Android app using Bluetooth. For that I hacked Google's BluetoothChat demo and after a short time I was using buttons and sliders to communicate with my Arduino. Why was that work? Eclipse...


A great advantage of using an Android device as the communication platform is the real-time outputs. This is very nice when debugging since you don't have to be tether with the laptop.

Edit 1: I later created an Arduino to Arduino link with bluetooth.

Edit 2: Here is similar code a later used for the minirccar

Android is smoking

This is my first Android development test using the NDK and OpenGL-ES. I quickly adapted some simulation code I found on the web and rewrote the rendering layer to make it compatible with OpenGl-ES. I also fixed a couple of bottlenecks to make it run faster. Here's a video of the result.



So far I like working with the Android NDK and OpenGL-ES although I'm not a big fan of the Eclipse IDE (development environment). Now I'm going to start a shippable project to really get the feel for this new platform.