Let's Make Robots!

Android controlled (via BT) Picaxe car

Controlled via audio signals coming from bluetooth connected to a phone

This is my second robot car. It is controlled wirelessly by an android phone with the help of a bluetooth headset.

The theory is that an android application plays four different audio frequencies (500 Hz, 1000 Hz, 2000 Hz and 3000 Hz) which comes out from the bluetooth headset's speaker, these audio signals are then fed to an Op Amp which amplifies them and sends them to picaxe which do functions accordingly.

I am using the count and select command on picaxe so it counts the pulses coming on b.7 pin and responds to it as i programmed.

The audio signals coming out of the BT headset's speaker port are analog and are of low voltages (less than 1 volt which picaxe can't count) so i have used an Op Amp (LM358) which converts them to digital pulses and that too at 5 volts!! :D In the picture below the black wire is going to picaxe and i also connected an Led which lights when an output signal is going out of op amp as an indicator. In the video it is shown working.


The android application. It has 4 buttons and each plays the audio frequency written on it.

freq.    action

500 -   move forward

1000-  turn left

2000-  move backwards

3000-  turn right

Some more pics->

I am using 4 AA size cells to power picaxe and Op Amp and two nokia (BL-C5) 3.7 volts 1000mAh batteries in series to drive two motors.

Video coming soon :)

Thank you :D



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that's very awesome sanc!!! specially that you've used those nokia batteires :) (wink wink, nudge nudge),  very cool!!!

Thanks Metal :)

This is my kinda thng! Good job sanc! :)

I love how you structured most of the robot with perf board. that is something that you dont see often enough! :) overall it is a very cool idea and design.

And yes, perf board makes a good and spacious base and makes it easier to mount other hardware just using male headers.

Thats pretty cool, with tone recognition. Good job. :)

How did you do the app for android?

My elder brother knows android. so, i asked him to make the app for me :p But it is not necessary to have an android app for this, any phone (or maybe laptops, PC) which has BT can be used by playing frequencies in the music player :)

I have robot controled via bluetooth. I am using pc ,but for competition a wanna use android :)

sorry I don't have the .apk file for my app but you can search for 'tone generator' on the android market, i remember i found one app that had preset function in which you can enter values and assign butons to those values of frequencies.