Sunday, July 31, 2011

DIY Telepresence Robot - Part 2

Parts List

Construction of the robot is more of an assembly task than a true manufacturing task.  A collection of high level parts loosely thrown together - the robot can be assembled quite quickly.  Construction of the body frame requires a small amount of craftmanship but even so - the whole robot can be built in a day (a weekend at most) using common tools.  Many of the parts are only found online, but some may be purchased locally if the price is competitive.  Here is the list of parts...

- iRobot Create Programmable Robot  $130

- APS Battery $70
Since we're going to be tapping the battery for the netbook, we want the highest capacity, fastest charging battery.

- Home Base Charger $70

- Create USB to Robot Cable $20

- Asus Eee PC 1015PE (or similar) ~$250
Stock in this exact model may be diminishing or hard to find at a good price.  Any netbook in that class should do however.  Higher priced ones are not better.  They just add stuff like larger hard drives, better battery, etc which you DO NOT NEED.  The battery is going to be removed from the unit and the software requirements are minimal.  Your primary constraint is weight.  2 to 2.5 lbs is ideal.  The voltage requirements on different models may vary from the 1015PE but the electrical components we will be using can accommodate a wide range of voltages so different computer models should not effect the electrical design.  More troublesome might be the form factor of the netbook.  The platform we will be building integrates the netbook battery cavity into the structure, so if another model's chassis differs dramatically from the 1015 then the build instructions may not transfer to it, and you will have to come up with your own structural solution.

- Microsoft LifeCam Cinema WebCam $55 (or less)
The netbook webcam sucks.  Picture quality, motion, light correction, and auto-focus are of utmost importance for navigation so you want a decent webcam.

- Eagletron PowerPod $180
A nifty little gadget that we will be used as the robot's neck.  It has a very strict weight limit of 3lbs.  That's why the netbook has to be very light.

- AnyVolt 3  $55
An awesome little gadget for generalized voltage conversion.  This will be used to convert the iRobot's battery voltage to the laptop's voltage.

- DB25 Breakout Board (BRKSD25M-R) $22
This is a bit of a splurge item.  Honestly you could just a get a $2 connector from Radio Shack and solder it, but I am lazy and terrible at soldering so this little item was gold for me.  I built the entire robot without having to do a single solder!  If you feel comfortable soldering, then save yourself a few bucks.

- EZ Tube Construction materials ~$20 ??? (lost my receipt so I don't have the exact pricing)
  - 1 x 100-100 Plain square aluminum tubing
  - 3 x 100-305 Composite T
  - 1 x 100-328 Adjustable Foot with plastic insert
These will form the body of the robot.  These guys have an unusable online ordering system so just phone in the order instead.

- Aluminum Sheet (6.5" x 12" x 0.04") $4
This sheet will be fashioned into a little "table" for the laptop and needs to be light but sturdy enough to support the laptop.  You can buy aluminum sheeting at Home Depot, but I think the thickness may be 0.032" which is a little too thin.  I found that 0.04 or even 0.05 thickness is about right.  I ordered mine online from this site because they offer a range of thicknesses and also can provide a custom cut which is convenient.  It is probably a good idea to pick up 2 of these because constructing the table is a precision task and is easy to mess up.

- Construction Materials
A few extra items that can be picked up at Home Depot, Lowes, and Radio Shack.
  - 4 x 1 1/4" 6-32 bolts
  - thin electrical wiring (20 or 22 gauge)
  - 1 1/4" x 1/4"-20 bolt (standard camera tripod size)
  - flange nut that fits the bolt
  - velcro
  - wire management clips

So all told, the total is something like $875 (parts) + $100 (shipping fees) + $25 (extras) = $1000
Tax isn't included here but the price is still pretty close to accurate.

Next -> Part 3: Building the Head


  1. Did you consider using the Eagletron PowerPod to just control the camera instead of the whole netBook? Perhaps you were trying to control the angle of the netBook screen for a better experience for viewers, but it may have made the whole stack a little more stable. Anyway.. This is really cool.

    Is anyone you know trying to port this to and iPad or Android tablet form factor?


  2. I have briefly considered that - maybe for a separate navigation camera. But the overall effectiveness of having the screen pointing towards where you are looking is just too compelling to change. Being able to make easy eye contact with people that are standing really makes it user friendly and creates an illusion of human embodiment that people respond to.

    I am currently doing work to enhance this effect even more by using a head mounted display to control the neck so that my head motions will be mimicked by the robot.

    I also pondered use of a tablet computer but several factors counted against them.
    1. They are 2-3 times as expensive as a netbook.
    2. Development is so much easier and faster on a fully featured OS than one of those half-ass operating systems.
    3. Mounting a tablet in a stable way seemed more difficult to me. I wish they had VESA mounts on the back but they don't.

    The more I have researched, it seems the best option would be to get a regular notebook computer and mount it to the base, detach the screen and mount it to the neck, and run a custom cable between them. But that project would require a good deal more courage to undertake.

  3. Thanks for your reply. I'm getting ready to embark using your basic concept and setup. I'll share any advancements or discoveries with you. Thanks for sharing what you have done.


  4. Stay tuned. I have been making some adjustments to the hardware to see if I can get past some of the problems that I have been experiencing. I will post updates in about a week if I find anything of significance.

  5. Would it be possible to use simpler and lower cost hardware instead of the Irobot platform with some kind of pc/motor contrôler interface ?