This is a Robot car which can be controlled using any mobile phone. This was a project I did years ago, while learning digital electronics in the college. It was a time when I knew only less about microcontroller programming else almost the whole circuit could be replaced by a small microcontroller. The mobile phone is placed inside the car. To control the car, just call that mobile phone in the car after enabling the DTMF keypad tones in the calling phone. Then press 2 to move forward, 8 for backward, 2/4 for left/right control.The following video shows it in action although it is not controlled by another phone in the video.
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Speech recognition in ROS/Linux has been has been traditionally done using projects like CMU-Sphinx or Julius. But they lack an efficient vocabulary and is not stable. So reliable speech recognition was confined to Windows/Mac users only. Initially I was using a windows virtual machine inside ubuntu to do speech processing, even though it was quite resource consuming. A good alternative is to use the speech recognition built into Chrome by Google. The speech samples are sent to Google’s servers for processing and they return the recognized speech and a confidence value.It is quite easy to use this possibility of speech recognition. It also offers an advantage of speaker independent recognition of speech. The only disadvantage is the delay caused in detection. It normally takes about 3 seconds for the speech to be recognized.A simple python script for speech recognition is shown below
I have also created a ROS package for speech recognition. It can be run by checking out theGithub repo, and running ’rosrun gspeech gspeech.py‘. It will publish two topics: /speech and /confidence. The first one is the detected speech while the latter one is the confidence level of detection
This Notice Board is quite smart. It is a re-purposed unused old LCD monitor. The messages to be displayed on the notice board ( an old LCD monitor) can be sent from any mobile phone. The user should also provide an authentication code for the message to be displayed. The video below shows it.
This curtain controller uses a microcontroller to control the opening of curtain veils, thus enabling the control of light intensity in the room. It features both automatic mode and manual override mode. In the automatic mode, we can set the preferred intensity level in the room using a pot and the control system will adjust the veils suitably to maintain the user set intensity level always. As the name indicates, in the manual override mode the user is free to choose any opening of the veils.
Circuit Diagram
URDF stands for Unified Robot Description Format, Which is an XML format for representing the model of the robot. More info about the URDF can be had from the tutorials at ros.org. Once we have the URDF model of our robot, we can use it in rviz to visualize what the robot is perceiving or use it in gazebo for simulation.
Here is a small video showcasing the URDF model of Chippu.
Here is a small video showcasing the URDF model of Chippu.
HSV color space is more often used in machine vision owing to its superior performance compared to RGB color space in varying illumination levels. Often thresholding and masking is done in HSV color space. So it is very important to know the HSV values of the color which we want to filter out. HSV color space of OpenCV is a bit complicated than other software programmes like Gimp, Photoshop etc.So I have written a small python script to grab frames from a camera, and print the HSV value of the pixel under the cursor
Screenshot
Chippu has now upgraded its hardware, and is now much smarter. The Atmega32 is replaced by a more powerful and feature rich Atmega128 based Wiring Board. It has 53 I/O pins, 8 analog inputs, 2 hardware serial ports, 6 PWM (analog outputs), SPI, TWI, 8 external interrupts pins. Also it can drive a maximum of 24 servo motors. Quite impressive. A motor control board based on L293D was also added. Here are a few shots.
I was using an Atmega32 based Arduino clone for the low level hardware control of my personal robot Chippu. But soon ran into problems as the code size increased and the inbuilt RAM of 2kb overflowed often, and it caused the ROS node running on Arduino to go out of sync. Also I needed to drive about 16 servo motors , and my Arduino permitted only a maximum of 12. So the only alternative was to go for a powerful Arduino Mega 2560.
Wiring Board V1.0
There are a handful of online shops in india that provides electronics components. Some of them specilizes in robotics components alone, while some specializes in embedded boards, while some others provides all types of components and boards. The prices of the same component varies greatly among different shops, so it is wise to refer as many shops before making a heavy purchase.
The shops are:
