DTMF Shield

PrintrCamBot v0.1

An open-source 3D-printable Dropcam carrier for Printrbot's challenge.

Summary

My name is Carlos García Saura, and I'm a student from Spain. I am a true fan of Printrbot, and I also love making robots, so you can imagine my face when I saw this:

I would love to get my hands on a Printrbot Simple, maybe this could be my chance! :P

Basically, my approach is based on two different ideas:

• Since the Dropcam has two-way audio incorporated, why not use that to send DTMF audio tones to control the robot? (more details below)
• A "flying fox" robot could easily travel around Printrbot's warehouse without disturbing their workspace You would just need to place a tense wire from one side to the other of the place to monitor.

I would love to see this robot moving around Printrbot's HQ

(6 June 2013) DTMF discarded, new approach!

Brook has told me that Dropcam's speaker can only be controlled by the owner (D'Oh!).
So here is the new setup idea:

• The robot is kept really simple: Replace the DTMF board with a cheap Bluetooth module. I can make a compact electronics board for this.
• In any computer, plug a USB bluetooth dongle. A simple Python script will then communicate with both the robot AND Printrbot's server. At first I thought of using a Raspberry Pi, but this is cheaper and will work as well! :)
• At Printrbot's server, install a simple script. Its mission is to present users with a simple controller interface, and queue them for "time slots". This way you can easily send commands to the robot from the server.

The cost is still very low: Arduino board in the robot (15$) + Cheap Bluetooth Module ($5) + Bluetooth USB dongle (~$10, free if you already have one!)
And the robot itself could use (depending on the design you finally choose) three or four servos + a Li-Po battery (with 5V regulator).

Links of interest:

• Python and Bluetooth http://homepages.ius.edu/RWISMAN/C490/html/PythonandBluetooth.htm
• Bluetooth communication between Arduino and PyBluez http://stackoverflow.com/questions/15486570/bluetooth-communication-between-arduino-and-pybluez
• Python interaction with website http://ubuntuforums.org/showthread.php?t=624944
• Web interaction using Python http://www.hackthissite.org/articles/read/1053/
• How to use Python in the web http://docs.python.org/3.1/howto/webservers.html
• Python application communicating with a web server http://stackoverflow.com/questions/7975031/python-application-communicating-with-a-web-server-ideas
• Internet Controlled Robot with User Queue System http://forums.parallax.com/showthread.php/139284-Live-Internet-Controlled-Robot-with-User-Queue-System

(11 June 2013) Update: Pause!

Sadly, it won't be possible for me to develop the web interface (at least soon) :S
I'm more of a hardware guy, so my first Web UI attempts have been a bit of a disaster! Not to mention that the code needs to be robust against hacker attacks: I have very little experience dealing with those kind of issues.

Also, there is too many stuff for me to keep up with before I leave to the US next week (will be in California for two months).
It would be great to have a Printrbot Simple that I can leave at my cousins place, so please let us know if we could have some discount! :)

Anyway, it has been a honor to collaborate with this design and am willing to help with electronics/hardware :) Can't wait to control your Dropcam!
Thank you Printrbot for promoting Open Source, and good luck to the rest of participants!

Video (5 June 2013)

For this test, I fixed my Android Phone to the back of the robot, and added a heavy battery on the other side as a weight to stabilize the robot. The additional weight plus the thin wire that I have used make the robot quite unstable (it is the first test, what did you expect? ;)

I have then stabilished a call via Skype (for the DropCam, this will be done pressing the "Talk" button, and then using a DTMF generator on any smartphone, holding it next to the mic).

The dial-up tones coming out from the speaker of the smartphone -I insist, this could be directly the Dropcam- are then interpreted by the DTMF decoder + Arduino Nano to move the servos.

VIDEO: http://www.youtube.com/watch?v=sOZ26wGzT1U

Unfortunately, I don't have a Dropcam to do proper tests. But as it is shown in the video, this robot can control a Dropcam via internet using its speaker.

Details

I have printed all the parts using my Printrbot Jr, which I bought last summer. This printer feels very lonely and would love to have a Printrbot Simple as a friend :)
 The parts have been designed with OpenScad and are parametric, don't forget to add the real diameter of the Dropcam before printing!

For the electronics, I have developed a DTMF decoder board and manufactured it in Cyclone PCB Factory (https://github.com/carlosgs/Cyclone-PCB-Factory). It has been the first circuit manufactured with this new open-hardware machine! :P
If Printrbot likes my idea, I will send them the electronics assembled so they don't need to worry about it.

Regarding Dropcam's power supply

The tray of the robot has been designed to carry a medium-sized Li-Po battery, and also a 5V regulator. This would supply the 2A required by the Dropcam, and the few milliamps required by the rest of the robot.

To-Do list

• Add counter-balance weight for the main frame
• Add second "travel wheel" to improve stability
• Wait for Printrbot's feedback! :)

Credit

This project has been possible thanks to the following work:

• MiniSkyBot Wheel by Obijuan (https://github.com/Obijuan/Miniskybot)
• Dropcam Tripod Mount by Reuben (http://www.thingiverse.com/thing:39078)
• Yazzo Servo Side Shelf Mount by WilliamAAdams (http://www.thingiverse.com/thing:6668)
• Skype-controlled robot using smartphone and DTMF tones by Janisalnis (http://www.instructables.com/id/Skype-controlled-robot-using-smartphone-and-DTMF-t/)
• Electret mic interfacing by Chrille2k and BillHo (http://forum.arduino.cc/index.php/topic,19052.0.html)
• Kicad Arduino nano (YJ_arduino: component and module) by Yann Jautard

License

License: Attribution - Share Alike - Creative Commons (http://creativecommons.org/licenses/by-sa/3.0/)

Author:

• Carlosgs