Can someone build me a Pi Bot?

[johnny555]

Curious if anyone would take a gig to build me a Pi Bot? Here's what I'm looking to have produced:

- a mobile bot (either 2 wheel or 4 wheel is okay); the smaller the better
- neither speed nor terrain-handling are concerns
- webcam-enabled, transmitting video over wi-fi
- battery operated
- ideally I'm shooting for remote control over a browser-based interface (actually, the 'ideal' ideal would be open access - not unlike Sid the Robot, where users queue to access the bot for 'x' amount of time, but I'd likely treat this functionality outside the scope of an initial project)

FYI - I've given it a go, but as a non-programmer/engineer, I'm moving wayyy too slow. This will be a prototype to explore possible applications (in what? I don't know - gaming? Education? Mars surface exploration?) At the very least, I kinda just want to play with one because they seem awesome.

If it matters, I'm in the Philadelphia area. Get at me if interested!

[Ravenous]

How far have you got? If you already have motors and a motor driver why not say what you have - someone may be able to suggest a wiring diagram and code to get started.

[johnny555]

What I have:

- Raspberry Pi (Model B), 4 GB SD with NOOBS pre-installed
- Pi camera module
- wi-fi dongle
- a very cheap 2 wheel (plus caster roller) platform (it's this one)

I've struggled with silly/basic issues, like proper video output, weird connectivity issues in getting the wi-fi going, haven't yet delved into the camera yet. I really would love to handle this on my own, or perhaps with a partner to get some hands-on appreciation (and I'm separately seeking someone like that in my geography), but I really just want to fast-forward to the evaluation period so I can answer some questions, like: what is the video latency? how precise is the turning? battery life? maybe most importantly, is it fun?

Figured I'd tap into the wide talent pool of those who have been-there-done-that!

[penguintutor]

That is very similar to the Magician Chassis that I've been working on.

I've put a quick overview at: http://www.penguintutor.com/electronics/rubyrobot but I'm still working on the documentation.

Hopefully I should have something available in a few days time.

[johnny555]

Wow, you're not kiddin' - that's precisely what I'm trying to build, same chassis and all. I just liked your FB page, so I'll stay tuned for that documentation. Great work!

[mikronauts]

I have that exact chassis sitting in front of me, with:

- Raspberry Pi (Model B)
- 8GB uSD card with Raspbian
- wifi stick
- motor driver board
- RoboPi advanced robot controller board
- small breadboard
- HC-SR04 ultrasonic distance sensor

Beside me, not yet integrated, is the Pi camera module.

Since you don't have a RoboPi on your robot, may I recommend the February 2014 issue of Servo?

I think you'll find my SPRITE article (building an extremely simple/cheap robot controller for the Pi) helpful as it shows how to install all the needed software, configure WiFi, etc.

I'll be posting to the RoboPi thread as I release demos and apps.

RoboPi information: http://www.mikronauts.com/raspberry-pi/robopi/
RoboPi thread here: http://www.raspberrypi.org/forum/viewto ... 37&t=68416

[johnny555]

Very cool - I'll give a look for that SPRITE article. Can you give me a basic explanation of what benefits are derived from the RoboPi? Like, what additional applications or uses might it allow for?

I'll keep an eye on that thread - interested to see the completed unit with the cam (and the first-person view, especially).

[IWM Electronics]

i have a nice little starter kit i do worldwide shipping will also be releasing a couple more cheaper models hopefully next week
http://www.ebay.co.uk/itm/221373460125? ... 1555.l2649

[mikronauts]

Very cool - I'll give a look for that SPRITE article.

I hope you enjoy it! The cover shot was my SPRITE Raspberry Pi based bot.

http://store.servomagazine.com/home.php?cat=475

A digital subscription is only $20/year, and gives you access to past digital issues. That's the subscription I have.

FYI, I also have articles in Sept.2011 (got the cover then as well) and Oct.2011

Can you give me a basic explanation of what benefits are derived from the RoboPi? Like, what additional applications or uses might it allow for?

Sure!

Basically RoboPi is an eight-core 32 bit RISC microcontroller running at 100Mhz. 10ns timing grain is possible for hard real time I/O by writing assembler code for it. The development tools can run right on the Pi, and include assembly language, Spin, and C/C++.

Think of it as an extremely versatile and high speed I/O processor for the Raspberry Pi, with robotics being one of its primary uses. It off-loads hard real time I/O from the Pi, and comes with firmware to make it extremely easy to use from C. (later I will also make a Python interface to RoboPi, and possibly even Scratch)

RoboPi connects to the Raspberry Pi over the 3.3V Pi serial port, and uses only a single additional GPIO (#17) to reset RoboPi when programming it from the Pi. If you don't want to program RoboPi directly, I made RoboPiLib so all you do is write code in C/C++, include "RoboPiLib.h", and link with "RoboPiLib.o". The API is very simple, and is based on Wiring/Arduino.

RoboPi adds 24 flexible digital I/O's, with each digital I/O being usable as

- digital input
- digital output
- servo output
- PWM output

RoboPi also has an eight channel 12 bit analog to digital converter, and on-board voltage regulation to 3.3V from Pi's 5V

There is a lot more detail on the product page, including the Spin API, and assembly documentation.

http://www.mikronauts.com/raspberry-pi/robopi/

(the C/C++ API is almost identical, and should be posted before Monday - I am just cleaning it up and adding comments)

Please don't hesitate to ask any questions you may have about RoboPi in the RoboPi thread on this forum!

http://www.raspberrypi.org/forum/viewto ... 37&t=68416

I'll keep an eye on that thread - interested to see the completed unit with the cam (and the first-person view, especially).

[mikronauts]

I took a quick shot of my 2WD Magician RoboPi test bed:


(Right-Click "View Image" to see a larger version)

[abroun]

Hi there,

I've got a tutorial on building a Raspberry Pi camera robot that you can drive around using a web browser on a tablet, phone or pc, which you can find here. If you've got any questions about the build process or source code, please just ask.

Regards

Alan

[mikronauts]

Alan,

Nice tutorial!

How well does the flex cable work with the pan/tilt mount?

I know, it is called a 'flex' cable, but I am curious as to how it stands up to the torsion from the pan/tilt head.

[abroun]

Hi there,

Thanks for the kind comment.

The flex cable works reasonably well, although you do need to be careful when routing it originally to make sure that it doesn't snag on anything. The main point of stress comes when the head turns to the right, but on the robot pictured in the tutorial, which has seen very regular use over the last couple of months, the cable seems to be holding up well.

I'm hoping to refine the robot in the future, to make it more robust, and to make it into a proper kit, so I'll probably look at using a longer camera cable then, so that it can be routed over the top of the pan/tilt unit, rather than through it.

Regards

Alan

[johnny555]

Paydirt! That's excellent, Alan. I'll see if I can follow along some of these tutorials and let you know what comes out on the other end!

Thanks, all.