Rover 5 progress - test drive and FPV video!

So far it's looking pretty good. I couldn't help myself! Just HADS TA drive it! XD Everything is VERY temporarily double sided taped in place.

At the back is one of my Mega rigs with Sparkfun XBee, GPS and Monster Motor shields. On top of those is a DFRobot prototyping shield with a LSM303DLH compass/accelerometer. The GPS is an EM-406. Currently the XBee is a Series 1 XBee Pro 60mW, but I have a pair of 60mW 900 Pro's for when I want to use analogue video.

The camera is a Swann Wireless digital security camera/receiver kit. When you watch the FPV video, remember both the XBee and the video link are both on 2.4Ghz!

There have been a few issues. The Wild Thumper wheels look great, give way better ground clearance than the stock tracks, but...

It's one or the other I'm afraid, tracks or wheels. All 4 axles have been ground half flat to go through the tread road wheels. When you use the Wild Thumper wheel adaptor it leaves 10 -12 mm of half ground down, fairly soft axle. I managed to bend an axle this morning, otherwise I would have shot some tread video.

The other @#$$%@ thing is those stupid $^%#!! "thumb" joysticks! I know they are cheap, but wow! There are 4 here, NONE of them have the same range or centre value, I tried all 4, used the least bad one. But I did manage to get fairly smooth control.

I can see a D15 going on my Tx rig and using a "real" joystick that has trim controls.

Now that I have control from either a keyboard or my joystick, I will add heading hold. That way I'll be able to point and let it drive itself.

In the prototyping stage is a sonar unit, I've left a large area up front for that.

I have a lot more body to build yet, I want this rover to be a bit weather proof.

Here is a longer video of Rover5, on patrol!

Here is the code for the Tx. Is there another way to do this?

// Simple controller for my Rover 5
// On the rover end, direction keys are mapped out for a numeric keypad.
// speed is selected from z- 25%, x- 50%, c- 75%, v- 100%.
// at the moment any other key stops the rover.
// this programme takes X/Y values from a Sparkfun joystick shield
// and translates the 2 axis into a character from "1" to "9"
// at the same time we get a "speed" value based on how much stick was given.
// "z" -> "v"
// the speed command is sent first, then the direction command.
// I'm running this code on a Mega.

#define Joy_X_pin A0 
#define Joy_Y_pin A1
#define statusPin 13

int rawX;
int rawY;
int xspeed;
int yspeed;
boolean ledState = false;
char speedCom;
char steerCom;
char speedArray[7][7] ={

char steerArray[7][7] ={


void setup(void)
  Serial.begin(9600);           //Turn on the Serial Port at 9600 bps
  Serial3.begin(9600);          //Turn on the XBee Serial Port at 9600 bps
  pinMode(statusPin, OUTPUT);

void loop(void)
  rawX = analogRead(Joy_X_pin);
  rawY = analogRead(Joy_Y_pin);
  xspeed = map(rawX,0,1023,0,6);
  yspeed = map(rawY,0,1023,0,6);

  speedCom = speedArray[yspeed][xspeed];

  steerCom = steerArray[yspeed][xspeed];

 ledState = !ledState;
  if (ledState) {

This works really well, but the way I've had to map out the dodgy thumb stick is a bit clunky? :)

Would doing a "calibration" step (and maybe storing the values in EEPROM) like the old PC games help? That is, record the center, upper-left, and lower-right values - so you know what is "zero position" (center), and min/max values...?

I tried that crOsh, first thing I tried it would work with my CH Pro, Logitech or any of the other "real" joysticks I have. But these thumb sticks are terrible and not consistent.

It might not help we have had a 28C temperature change today, it's hot, was warm when I shot the video this morning.

None of my PC sticks behave like this.

But my PC game pad does.

To Mars! :)

Will the rover partrol at night?

When you watch the FPV video, remember both the XBee and the video link are both on 2.4Ghz!

I'd really like to see that but I didn't find it? Hmm Edit , this evening there are now 2 videos

Nice demo! "Field Road, Jupiter Creek" huh? I thought the landscape looked familiar. :)

South Australia, I gather.

The other @#$$%@ thing is those stupid $^%#!! "thumb" joysticks!

I had pretty good success with the Wii nunchuk as the controller.

Nice one.

Any thoughts on the benefits o otherwise of a 6x6 chassis like the wild thumper? I wonder about the strain placed on axles with skid steering.


liudr: To Mars! :)

Will the rover partrol at night?

Funny you should ask that! For a "Security" camera, this one is pretty hopeless outside. If something is in the main "footprint" of the illuminator, you can sorta see it! On the box it says 26ft/8m, but there is no way it is that good. If it was patrolling in a building it would be great! Plenty of light then!

Once I repair/modify/strengthen the axles I will shoot a night patrol video with my Sony. The Rover's IR light is so freakin bright for my Sony handicam! If the "Security" camera was that good, I'd be happy!

The other necessity for night driving is at the very least a compass!

Graynomad: Nice one.

Any thoughts on the benefits o otherwise of a 6x6 chassis like the wild thumper? I wonder about the strain placed on axles with skid steering.


I've been thinking about that! With a rigid chassis and no suspension like this, 6 wheels would be a hassle. 4 wheels with no suspension is bad enough! I've had a shallow depression (not EVEN a HOLE!) stop this beast dead!

What happens is 1 wheel looses contact with the ground, spins up with no load, hogs all the current and the other 3 wheels just "sorta chatter a bit". It is exactly like having a 4WD car and getting one wheel to spin, diff action takes over and that's it.

To fix this problem, I ordered 2 Pololu Dual VNH5019 motor driver shields. There will be a separate PWM channel, direction and enable line for each wheel. I will use the optical encoders on each wheel and monitor wheel spin/slip and apply a correction to the offending wheel.



Right now I should point out if you want to put the wild thumper wheels on, you are going to need to upgrade the axles. Out of the box the axles are simply too flimsy for 120mm wheels. Another point is the stupid hex head screw that secures the wheel adapter to the shaft is a joke.


My plan is to drill out the wheel adaptor all the way through for the 4mm shaft to go all the way through the wheel rim, then I will use a nut and washer.

Seriously, I was looking at the 4 and 6 wheel Wild Thumper chassis, as well as the "Off Road" rover they sell, but...

If I had spent the kind of dollars we are talking here, I would want to have seen a MUCH better strategy for mounting the wheels. And when you look at the rest of the construction, I'm convinced I can build a better chassis than either Wild Thumper. When you put great, big, off road wheels on your rover, I think it kinda implies "off road" and "all weather"! Maybe I'm expecting to much for a "hobbiest" platform?

I love this Rover 5 platform! It has some bad points, but for the price it's great!

Pro's (so far) - so much scope to mod!! - even with only 6 2500 mAh Nimh batteries it has a fair bit of grunt. - seems to be able to carry a fair bit of weight. - 120mm wheels give it GREAT ground clearance!

Con's (so far) - out of the box the treads had warped the sides of the chassis quite badly. - needs a LiPo battery, 6 Nimh can't possibly supply enough current at anything below 25-30% PWM "throttle". - the supplied tracks give you about 15mm of ground clearance! maybe 40mm to the chassis bottom!

As a final point, when you watch both video's, that was the SAME 6 cell battery pack! Which is pretty good going considering it is fairly rough terrain and the rover covered 500 - 600 metres! I would have driven further, but bent an axle.

cyberteque: For a "Security" camera, this one is pretty hopeless outside.

Plus, it's incredibly noisy. :)

[quote author=Nick Gammon link=topic=89196.msg680008#msg680008 date=1328507558]

cyberteque: For a "Security" camera, this one is pretty hopeless outside.

Plus, it's incredibly noisy. :) [/quote] But is totally immune to other 2.4Ghz signals! The "funky" colour is due to the camera not having an IR filter. That's why the clouds and sky are such weird colours.

If you know the plant species in the video's it's really quite interesting how much they different they look in IR.

I've seen this effect before with IR film in my SLR.

I'm glad I bought a pair of 900Mhz XBee modules though! Going to go analogue video link with a better camera.