Rover 4WD (or more) waterproof, self rechargeable

Hi all, i'd like to start a project to build a 4WD rover. I want that it has to go across a a cultivated land transmitting video. Obviously it has to be (at least) waterproof to not be damaged by the rain or i thought it could be equipped with a cover which activates through a rain sensor . Moreover i'd like that it has to go back "home" when the battery is low and there will be something to recharge the battery without connection..something like roomba (or similar ) which go back to "home station" and recharge itself without a physical connection.

I hope i have been clear in my explanation..:) Thanks to all who wants to help me :)

The Roomba dock uses a physical connection: http://www.girr.org/random_stuff/roomba_dock.jpg

k0ral: i'd like to start a project to build a 4WD rover. I want that it has to go across a a cultivated land transmitting video. Obviously it has to be (at least) waterproof to not be damaged by the rain or i thought it could be equipped with a cover which activates through a rain sensor .

My advice would be to start with something smaller, and work your way up. Build a vehicle that can send back video remotely and pilot it around your house or apartment, before trying to build something that can work outside.

The main reason is cost; to build a machine that can travel outdoors on varied terrain for long periods (more than 30 minutes), be weatherproof, etc - will not be inexpensive. Expect to spend at least or more than $200.00 USD (for anything that isn't a "toy"). You will likely find that your machine will need to be fairly large, to cope with the terrain encountered outdoors; greater size means more weight, larger motors, larger motor controllers, larger batteries, larger budget.

If you insist on going this route though, and have the budget - I would advise you to spend the money on the chassis - specifically a Traxxas E-Maxx RTR. Everything you need will be included (including a radio); interfacing to the Arduino is simple (steering servo and ESC - just use the Servo library). Add on your video system (900 MHz or 2.4 GHz analog - or maybe an 802.11x IP camera) and your Arduino system, plus sensors, etc (you'll also want to add an SBEC or something to power the Arduino and such from the vehicle's battery).

Since the E-Maxx is a 4WD off-road and very capable RC truck chassis platform, meant to be driven in dirt, grass, damp areas (not through water, though - not without some major mods that cost $$$ - but a little rain won't hurt it) - it is perfect, and isn't too large.

For control, route the car's receiver into the Arduino, and use pulseIn() to read the signals, decode them, then send the outputs to the servo(s) and ESC. With sensors, you could use this to record your actions, or take over your actions (set it up, perhaps, to prevent the vehicle from running into a rock if an ultrasonic sensor detects something - or have a tilt sensor measure angle of the body, and prevent you from going down a steep hill that would cause a tumble, etc). Check out the code at SparkFun for the Dagu Wild Thumper control board (ATMega328 based) which is basically this entire system (the Dagu Wild Thumper is a 6WD platform that would be perfect for what you want to do as well - but it makes the Traxxas E-Maxx look cheap).

cr0sh:

k0ral: i'd like to start a project to build a 4WD rover. I want that it has to go across a a cultivated land transmitting video. Obviously it has to be (at least) waterproof to not be damaged by the rain or i thought it could be equipped with a cover which activates through a rain sensor .

My advice would be to start with something smaller, and work your way up. Build a vehicle that can send back video remotely and pilot it around your house or apartment, before trying to build something that can work outside.

The main reason is cost; to build a machine that can travel outdoors on varied terrain for long periods (more than 30 minutes), be weatherproof, etc - will not be inexpensive. Expect to spend at least or more than $200.00 USD (for anything that isn't a "toy"). You will likely find that your machine will need to be fairly large, to cope with the terrain encountered outdoors; greater size means more weight, larger motors, larger motor controllers, larger batteries, larger budget.

If you insist on going this route though, and have the budget - I would advise you to spend the money on the chassis - specifically a Traxxas E-Maxx RTR. Everything you need will be included (including a radio); interfacing to the Arduino is simple (steering servo and ESC - just use the Servo library). Add on your video system (900 MHz or 2.4 GHz analog - or maybe an 802.11x IP camera) and your Arduino system, plus sensors, etc (you'll also want to add an SBEC or something to power the Arduino and such from the vehicle's battery).

Since the E-Maxx is a 4WD off-road and very capable RC truck chassis platform, meant to be driven in dirt, grass, damp areas (not through water, though - not without some major mods that cost $$$ - but a little rain won't hurt it) - it is perfect, and isn't too large.

For control, route the car's receiver into the Arduino, and use pulseIn() to read the signals, decode them, then send the outputs to the servo(s) and ESC. With sensors, you could use this to record your actions, or take over your actions (set it up, perhaps, to prevent the vehicle from running into a rock if an ultrasonic sensor detects something - or have a tilt sensor measure angle of the body, and prevent you from going down a steep hill that would cause a tumble, etc). Check out the code at SparkFun for the Dagu Wild Thumper control board (ATMega328 based) which is basically this entire system (the Dagu Wild Thumper is a 6WD platform that would be perfect for what you want to do as well - but it makes the Traxxas E-Maxx look cheap).

Thanks cr0sh for your answer. I have seen the prices oht Traxxas but..it's over 450$..and this is too high because i have to add the camera and other sensors.

I am a very newbie with 4WD...what do you think about this http://www.der-schweighofer.at/it/prodotti/119196/ab_scout_rc_rtr_4wd_rock_crawler_mit_2.4ghz_rc-anlage

Do you think is it possibile to add Arduino on it? I can see in the video that if it does what i see..this is enough for me. I don't want to run on the ground, but i only want to be sure that it can move through a ground with few stones but not too big.

Thanks for your advice!

k0ral:
I have seen the prices oht Traxxas but…it’s over 450$…and this is too high because i have to add the camera and other sensors.

Well - it kinda depends on where you buy one, too - for example, here in the States at one of our national auto-parts stores called “Pep-Boys” - they tend to sell the E-Maxx (not sure why they sell toys, but they do) for around $250.00 or so when it’s on sale. Anyhoo…

k0ral:
I am a very newbie with 4WD…what do you think about this
http://www.der-schweighofer.at/it/prodotti/119196/ab_scout_rc_rtr_4wd_rock_crawler_mit_2.4ghz_rc-anlage

Do you think is it possibile to add Arduino on it?

Looks smaller than the E-Maxx, but yes - and Arduino could be added to it - it appears to use hobby parts like the RC receiver, ESC, and servos (but it seems that maybe you need to buy the battery and charger separately?). I can’t tell whether it has a BEC (battery eliminator) for the receiver and servos, or if it does, what voltage it runs at (maybe it has one off the ESC). Many S/BEC systems supply 6 volts, instead of 5 volts; if so, you can’t use it (easily) for powering the Arduino. You might need to get a y-connector to place between the battery and the car, and then build a custom connector to plug into the y-connector (from the battery) to the barrel jack of the Arduino, which would work OK. For the camera and such - that might need some more ingenuity, but it could be done.

k0ral:
I can see in the video that if it does what i see…this is enough for me. I don’t want to run on the ground, but i only want to be sure that it can move through a ground with few stones but not too big.

I just wouldn’t expect something like this to be able to travel for extremely long distances; maybe a few hundred meters or so - the main issue would be the amount of time the battery could supply energy for the motor and everything else - in many cases this is only for 15-20 minutes, depending on how “hard” the vehicle is run. You could potentially get a larger capacity battery, or invest in a better ESC (more efficient) and/or motor (lower current consumption).

I don’t know how well this machine would do in wet conditions - those servos and the motor seem fairly exposed. If you could invest in waterproof servos (like used for RC sail-boats and such), and somehow enclose the motor in such a manner to reduce the chances of it getting wet (and don’t drive thru puddles or streams) - it would probably be OK.

Just to think about an alternative... What do you think about this one? https://www.youtube.com/watch?v=ntlI-pDUxPE#t=35 I think that it's simple and the platform could be useful to add cameras, sensors etc..

Again..i don't need to go fast, but just to go and climb some little obstacles :)

What do you think i need to build something like the one in the video? 6 stepper-motors and 6 springs?