The Fan-Pushed R/C Cart a.k.a. The Computer Cart

I've decided to do something different and am actually telling you, the viewer, now that this is a work in progress. As I write this, the cart is still being perfected. Also this is a video documentary, with the "steps" being the different versions explained both in video and text, and running footage of the later versions.

The Computer Cart. It's not blistering fast. It can't turn on a dime. It can't go in reverse. It's neither the biggest nor smallest r/c car out there, and knex r/c cars aren't anything new (in fact, I believe knex themselves sell a few r/c building sets). So why? What was the point of this? The answer; to enter it as a TSA project (1%) and just for pure fun (99%!). We wanted to make an r/c vehicle so unique that it would be awesome and fun to drive even if it wasn't the biggest, baddest r/c cart. I think we can say we accomplished that more or less judging from the picture. That is the current version as of the day this video log was originally posted. Looking at it, it is a cart built out of knex, riding on mismatched wheels, controlled by a 6-channel r/c airplane transmitter and receiver and two servos(also off the airplane), powered by a 3 cell lithium polymer battery (also off the airplane) and a 5 volt regulator for the receiver, and pushed about by a computer fan. I think the cart speaks for itself! And this car looks radically different from the first versions. This video documentary will show this cart and its transformations as we go through the versions and improve the cart.

Oh I almost forgot, you might be wondering who built/contributed to this. Well:

Build Team
- Eduardo Perez
- Robert Meyers
- Mike Aleman
- Tray

Thank You To:
- Ryan Bishop (Donated Servo and First engine, the Nidec)
- HP (Donated second and current engine, the Delta)
- Mr. Doyle and Mr. Zimmerman (for letting us work on the project)

Step 1 Before We Begin...

     Lets talk about the engine and the different engine configurations the cart has gone through before settling on the Delta .  The engines are computer fans, completely stock.  From Version 1 to 4.5, the main (or sometimes only) drive engine was a Nidec Beta V Series TA 350DC Brushless Fan.  It arrived in a plastic green case at our little workshop room (Thank God our Tech teacher was nice enough to give us our own little room to build in so we don't have people constantly bugging us and touching our stuff.  It really does happen!).  We removed the green case.  It is the fan in the first picture.

A little info on this fan:

- It draws 2.3 amps at 12 volts
- It has an awesome feature built in which I call 'Safe Start' that first powers the fan on at low power to ensure the fan can spin.  Once spinning is confirmed (takes about 1.5 seconds), the fan kicks into high gear and spools to full speed.  If it can't spin, power is cut for 6-10 seconds before attempting to restart.
- It has pushed Version 4.5 to a top speed of about 5-6mph.  Not bad for just one computer fan pushing the cart (not the most frictionless thing, it's those knobby tires) and all the electronics.



     In addition to this fan, we've added a cool-master, traded it out for a slightly more powerful fan of unknown manufacturer, took that one off, and finally overhauled the main engine for the Delta.

     The Delta fan was also given to us, and what a find!  One of our build team member's dad works at HP, and they were throwing away a server rack cooling fan because it had a damaged front fan bearing, still ran though (more on the problem in the first running footage of Version 5).  Hp instead gave it to his dad, who gave it to our group.  Thank you HP!  It arrived at our little workshop room in a metal casing and, as seen in picture two, we immediately proceeded to remove it.  Now in all seriousness, we are not completely reckless; we have reasons for removing the grills.  The grills in both cases were removed to minimize size and weight.  Although the fans are mounted to a children's toy (knex frame), the cart will never be handled by children.  The people who DO handle the cart know not to stick any fingers or other body parts into the rotating blades.  Finally, The power is cut (battery unplugged) every time we deal with the fan.

Some info on this fan:

- It is a Delta GFB0912GHG Brushless Fan.
- It draws 3.3 amps at 12 volts.
- It has two counter-rotating fans in the same case!
- Each fan has the built in "Safe Start" feature.  The fans are independent from one another.
- Top Speed with this engine is unknown at this time (I just fixed a random throttle cutout problem, more on that in the first running footage of Version 5).

Now that we've talked about the engine a bit, let us go back to when this all began, Version 1.