The Wireless Missile Control Experience Pt 4

Well, in my last post I mentioned that I would like to add a couple of shelves above the control box for a laptop and a missile launcher.  What I did was add a second box identical to the control box.  This is the final result.

Overall View of myRobot.

Not the most attractive of robots I will admit but one very robust robot.  This guy comes into the ring at a whopping 95 lbs.   The drives are still capable of pushing this puppy around as in earlier videos and will still climb grades but care is require.  We now have a higher center of gravity.

Lower Deck, Drive Control and LAN Power Supply

The lower deck now houses the drive system, remote radio receiver and protection circuitry for myRobot.  The lid acts as a shelf for the battery/inverter that supplies 120 VAC to the LAN wireless router and if needed the laptop in the top deck.  You can see the remote receiver's blue antenna mast.

Inside Lower Deck

The wiring inside the lower deck has been changed slightly to allow for the addition of a fuse box.  This may be a very good idea, don't you think, with the weight of myRobot, and the current that the two lead acid batteries can supply mounted directly below.  There is a lot of power going on here.

New Radio Receiver Location

The radio receiver was relocated to keep the antenna feed as short as possible, feeding through the box and up the mast.

Second Deck Video and Fire Control

The second deck houses the laptop that controls video feed and missile fire control (to start ;-)  ). 

Here we see the wireless router that connects to the laptop inside, the primary video camera and the missile launcher with its own video for aiming.

HP Mini Laptop running Win 7

Inside we find the laptop, HP Mini running Win 7 Pro.  The control strategy here is to remote connect to this laptop from a remote laptop via MS Remote Desktop Connection programme available in Win 7 Pro, Windows Vista Pro and XP Pro.  The wireless router, Cisco Linksys, provides the private LAN connection between the remote laptop and myRobot's HP Mini.  Presently, the main video feed via USB and the missile launcher control and video feed again via USB feed into this laptop.  In future, I plan to include an embedded controller, EC1 offered by SPLat Controls to provide support functions like motor temperature, compass input, auxiliary control such as headlights, drive battery voltage levels and more and will be connected once again via USB and data display/control via their Windows SimpleHMI programme.  An Android phone app version can be downloaded into the phone and the same information displayed via BlueTooth.



The Remote Laptop connected to myRobot's HP Mini Via
MS Remote Desktop Connection programme

Now a demonstration video of myRobot.

This is it.  This pretty much ends myRobot.  My daughter-in-law is recovering quite nicely and my son has forgiven me.   Just in case you were wondering.  My wife, by the way, was my first kill.  If you have any questions or comments, sure, send me one.  If you want to know more about EC1, again.... give me a buzz.  As time permits, I may update this blog with EC1 projects. 

Thanks for your visit.  Take Care.

The Wireless Experience Pt 3

It was a dark and stormy night......  Actually that isn't too far off.  There's a weather system that just pasted this area in Florida called Andrea and we've had rain for well over a week.  I waited patiently for a dry day to test the wireless setup.

Before I continue, this is the remote control I decided to use.  It's a Futaba 2DR AM R162JE  R/C with 2  S3003 servos running at 27 Mhz.   I simply wired the two channel outputs from the receiver to the SaberTooth 2X12 motor drive control.  The SaberTooth has a setting to accept R/C signals and that's all there is to it.   SaberTooth will also power up the R/C receiver so you don't have to use a power pack.

This is an easy R/C control to get into.  First the price; I picked it up at Amazon for $50 including shipping.  There are two channels.... throttle and steering and that's all you need.  If the transmitter stops transmitting, SaberTooth has a dip option that will stop the drive dead in its tracks, which, is a great feature.  The last thing you need is the robot to run wild if you lose the wireless connection.

It took some time to get to this R/C.  My first choice was two SPLat controllers with radio options along with a modified game joy stick.  I actually did get a proto-type working with a game joy stick but it was proving to take a great deal of time and money.

Next I bought an old R/C along with a load of receivers and servos off eBay without doing the necessary research on R/C controls.  As a result, I discovered that the batteries to run these things cost an arm and leg and there wasn't one receiver whose crystal matched the transmitter's frequency.  Crystals cost the other arm and leg.  On top of all that, I had 7 channels along with trims and options that would easily befuddle a 747 commercial pilot.  With the new found knowledge gained from this adventure, I settled on the Futaba 2DR.

The whole idea of hacking is not to invent but to "steal"  technology that was intended for something else.  Building a wireless system from industrial embedded controllers was inventing.  On the other hand,  the R/C was intended to control a toy car or boat along with two servos; I hacked the servos for their connection wiring harness and wired the receiver into the SaberTooth.  A slight "steal".

The video you're about to see is the field test of the robot thus far with the wireless system installed.  One word of caution. When I was demonstrating the robot with the original wired controls to my brother-in-law, I accidentally ran over his foot.  I expected him to jump back when I came close but he didn't.  He was playing chicken and expected me to veer off at the last moment. I didn't.  I seriously considered taking him  to the hospital as he desperately tried to conceal the pain shooting up his leg from the crushed foot.   Well, his foot wasn't crushed and the pain did subside but a lesson learned.  As tempted as you may be, don't play chicken with this baby.

Wireless Control Drive System Field Test

One of the characteristics of the robot you may have noticed in the video was the tight turns it could perform and its ability to stop on a dime. Good characteristics if you plan to deploy robot in a area populated by people.

View of Transmitter Wired to the SaberTooth

Next:  Modification to add a couple of shelves above the control box for a laptop and a missile launcher (He he he he).  

The Drive System Pt 2

Control Box Containing the drive board and future control boards. 

Simple hand held control box with two pots (forward/reverse, left/right)

The very first thing I wanted to do was to get the drive system working.  The electric motors on this wheelchair seems to suffer from proprietary syndrome paralysis.  I was able to obtain the motor's part number quite easily off its nomenclature but failed to find its data sheets on the Internet nor was I able to convince the people at the company that manufactured the motor to provide me with anything.  The wheelchair manufacturer was of little help as well.  If you're going to hack an electric wheelchair, expect limited help from the manufacturer or distributor on data.

0.100 Shunt Resistor

What I did do was use a motor shunt resistor (0.100 ohm) in series with the motor and 12 VDC battery to document its locked rotor and running currents ratings.  With this information, I was able to select a motor drive.  In this case I selected  a model Sabertooth 2X12 manufactured by Dimension Engineering.  I also decided at this point to use analog input signals to control myRobot.  You have a number of options here from pots to computer interface.  I selected two pots simply because I wanted to complete the drive portion. 

Main Control Box

A look inside the control box presently containing the drive board, and battery hookup and distribution.  The motor leads can be seen at the top left and right corners.  The control lead to the hand held control box can be seen leading from the drive board an threading out at the bottom left corner. 

The plan is to eventual put into the left side an embedded controller.  Preferable a SPLat MMi202.  This controller would provide wireless control via a hand held joystick wired to a transmitter.  It would also provide I/O abilities interfaced with the laptop via RS232.  At the moment, I'm also considering an Arduino UNO as a possible choice.  More on that later.

Drive System Field Test

This is the field test of the drive system.  Actually, this the second test.  The first test was conducted in the car port next to my car.  I didn't programme the dip switches properly and as a result the controls didn't behave as expected.  I now have a new dent on the side of my car.  Need I say more about where to test your machine?  By the way, turn down the volume.  You're listening to everything from the jet overhead to the lawnman next door.