Let's Make Robots!

ArduPi Webcam Tankbot

Web controllable mobile platform for webcam mounted on pan/tilt turret

This is my first robot project though I have been working with Microcontrollers and Embedded Linux for a little while. As of writing (3/1/13) this is still very much a work in progress, but most of the hardware construction has been completed. This robot will provide a remotely controlled, mobile platform for a pan/tilt webcam. It is based on the excellent Tamiya Tracked Chassis Kit with the Dual DC Motors connected to the Arduino Motor Shield R3 via the Screw Terminal. The Pan/Tilt function is provided by two Tinkerkit Servos which also allows them to be connected to the Motor Shield without taking up additional pins. The webcam is connected via USB to the Raspberry Pi and streamed to an online server using MJPG-Streamer and an Edimax wifi dongle. Control for the Arduino can be provided via Bluetooth Bee, or XBee but the eventual goal is to connect and control the Arduino from the Raspberry Pi. As the RPi USB ports will be filled up with the webcam and wifi, connection will likely be achieved via GPIO.

 

Side view Ardu-Pi v1.3

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So after a long hiatus (partially due to picky Arduino drivers on my Ubuntu machine/partially due to the lack of new features being added to the Johnny5 Library) I'm taking another stab at controlling the rover from a web-based interface...  

There are several recent developments in the realm of embedded linux that open up new possibilities for this project.

   1. Beaglebone Black-  BB has always been out there for those looking for more punch than an Arduino can provide.  But at over $100 it was pretty much limited to experts and/or professionals willing to make the investment.  With the BBB they are providing similar functionality to the original, but by bringing the price down to $45, they are now a legitimate competitor for the Raspberry Pi/MicroPC space.  For my own project needs the BBB appeals through its combination of computing power (enough to run Ubuntu or Android) and the equivalent of two 32Bit Micrcontrollers.  Most importantly is the fact that it runs on node.js by default so no more need for installing node on the Pi...  The biggest drawback so far is the tiny developer community in comparison with Arduino or RPi.  Hopefully this will change with time, but the manufacturers have to be more proactive in making it more accessible to the average Arduino/Pi user.  As it stands now its very difficult to find other projects using the BBB in robotics, even though theres no shortage of articles claiming how perfectly suited it is.

  2. pcDuino/other Android-based MiniPCs-  Maker Blogs were all over these Chinese-made Allwinner A10-based Android sticks a year ago as "Raspberry Pi Killers"...  Well... the RPi seems to be alive and well the last I checked, and the reason again comes down to RPi's understanding of documentation and community building.  The A10 MiniPCs on the other hand often come from generic manufacturers with no documentation whatsoever.  A major exception can be found through sparkfun.com and is known as the pcDuino (http://www.pcduino.com/).  The pcDuino is based on an A10 chip, but also includes a UART and headers to interface directly with Arduino shields.  It ships with Ubuntu by default but can also boot Ubuntu or anything other Linux Distro.  While probably not as sturdy as a BBB, I've found knowledge gained from using Arduino and the RPi translates well.  Compared to the Pi, it works much better with Arduino which means users wouldnt have to learn an entirely new language like on the BBB.  Major drawbacks are its reliance on a cheap Chinese chipset and buggy interface.  Overall I'd put my money on the pcDuino for the short term and the BBB in the long term.

 3. Arduino Yun-  Despite vague promises of a release date in June, this board has yet to be released (as of 7/30/13).  Nevertheless, it shows great promise!  Not only is it a sub-$100 wifi shield for the Arduino, but it includes a Linux "system-on-a-chip" Who knows what the future will bring, but IMHO the YUN exemplifies all the qualities that made Arduino so dominant in the maker world in the first place.  Rather than try to compete with the RPi and MiniPCs they come up with something that builds on their strengths while providing new capabilities.  I'll definitely be watching this one closely...

 4. Ouya (?) - Admittedly an unconventional use case for a game console, but the Android platform is already playing double duty as a robotics client (see- http://www.bitcraze.se/2013/07/crazyflie-and-android/) and with the controller alone providing a potential wireless gamepad option (whereas proprietary controllers often require confusing bluetooth configurations...). Usage as a home automation dashboard is already well underway, so robotics applications should not be too much of a stretch... 

 5. Raspberry Pi Camera Module  While not as much of a departure from the original project goal, the RPi Camera module nonetheless adds new capabilities by connecting through the CSI bridge directly to the RPi rather than through a USB port.  This would allow room for a wifi dongle, and communication to Arduino directly through the USB instead of through the GPIO.  Still the module has its limitations in the fragile nature of its thin connection band.  This would probably prevent use of the servo turret...

Finally decided to take things up a notch and got a DFRobot Rover v2.2 PCB and chassis for the bot and thus far have had no regrets!  There was a certain degree of satisfaction knowing that the bot had been built from scratch, but the Rover design is pretty ingenius and not something that would be all that easy to replicate (at least not until some of the proposed FabLabs/Maker Spaces open up around here...).

 

https://picasaweb.google.com/lh/photo/nCbFZNVidfeBRsIH7YWmc9MTjNZETYmyPJy0liipFm0?feat=directlink  

 

 

 

  After all the excitement over finally getting my new robot controller/chassis from RobotShop today I forgot that theres about an 1/8 in. difference between the Tamiya "Double" Motor Gearbox (which I have) and the Tamiya "Twin" Motor Gearbox (which I don't have) and thats enough to render it useless...   Grrrr...  I guess its back to tge ordering form...

    If any folks have managed to rig a Tamiya "Double" Motor Gearbox to the DFRobotShop Rover V2. Chassis then please do save my weekend!

  Added an InfraRed WebCam for nightviewing.  Also got a new TL-WR703N Mini-Router to flash with this OpenWRT Webcam script-  http://shackspace.de/?p=3772.  This will require far less power and space than the Raspberry Pi when not controlling via web interface.  

   Most significant though is I managed to get a hold of the fantastic DFRobot Shop Rover V2 as just the PCB and side frames from RobotShop.com.  Have to say I've been really impressed with those guys!  They responded to a customer service ticket with a detailed price quote even though it was clear from the outset the order wouldn't be over $100...  Nice to find a supplier with good support like that...  Now I've just got to count the days till UPS gets here...

  I found this great Android App for Bluetooth control...  http://www.plastibots.com/index.php/2013/03/07/btbotcontrol/

It includes an example Arduino Sketch with some fancy xy string data stuff to drive it from a virtual joystick, but best of all it includes a window to view the image from the ip camera directly!

Of course, I should probably see if it actually works on my bot first...  I'll post the results once I give it a shot

Hello !

I build a similar robot.

.. as are the transmissions oriented?

Gear ratio is 12,7:1,  36,2:1,  114,7: 1 or 344,2:1 ??

 

Thanks

Gerhard

Hello !

I build a similar robot.

.. as are the transmissions oriented?

Gear ratio is 12,7:1,  36,2:1,  114,7: 1 or 344,2:1 ??

 

Thanks

Gerhard

I just used the standard configuration from the Tamiya Manual for now, but that'll change if I decide to rearrange.  A lot depends on whether or not I can find a battery pack which can be charged wirelessly, like the ones they use for cell phones.  If possible, I'll rebuild with the Battery and motors on the bottom akin to the DFRobot Rover so the battery can be "parked" on the charger.

Http://Www.linuxcircle.com got some really good source code for controlling the robots from a web browser. It also shows a simplet tutorial to feed live video using rapberry pi as the web server which broadcast the feed via a public ip address. The componets required for the robot are: 1. DFRobot Romeo 2. 4wd chassis 3. Raspberry Pi Other components including webcam, usb hub and wifi dongle. Have fun robot scripting!