I’ve been asking some questions in other posts but thought I should collate them all together in one place. So I’m making a robot to be used in a dusty environment that will need to be run for approx 8 hours in one charge. As a base unit I was thinking of the 4wd prowler and building up from that. So here goes my questions
Which encoders would be most suitable for these motors?
I’ve looked at some controllers and I think the sabertooth dual 12A controller would be suitable is this right?
For pwm control would I need an rc snubber circuit from an arguing uno to the controller?
In terms of a battery it’s hard to predict the power consumption since the terrain is awkward has lots of inclines so I think I’ll buy a 2000mah battery and see how that goes and buy another to suit. But what type is best I would’ve thought Lithium ion but not many choices here. Also what circuitry is required to be able to plug a charger in without removing the battery since it will all be in a sealed unit eventually? Can you also put different battery packs in series and charge in series too?
The robot will have a bumper sensor of sorts at the front to detect obstacles. I was thinking of having a rod with spring similar to a suspension that would hit a contact switch is there anything similar on the store? The search options are very limited.
Hi again @Rob762
as I wrote in the other thread, I’d not recommend the Prawler.
For dusty offroad conditions, why not use the Lynxmotion A4WD chassis (comes with encoders)
Their motors seem to be dustproof at least and the chassis protects internal parts better. #2 for the A4WD they recommend the 10A Sabertooth driver, but 12A will work even better #3 No, you can use the PWM capable pins of the arduino directly #4 I’d recommend NIMH batteries (eg. 12V 2.8Ah is available) because they can take some abuse (deep discharge, overcharging and fast charge)
8h runtime is a challenge, except you can add a huge solar panel. You’d have to drive very slow, which is stressful for the controller and motor. #5 there is a Lynxmotion bumper switch kit which is probably not suitable for outdoor use, but it’s a starting point for your own design
Thanks for replying. Im mainly buying the kit for the motors and wheels was going to make a box itself sealed drill some holes and use a shaft seal. I decided to go for the prowler mainly because it had plenty of details of the motor specs that i couldnt find on the lynxmotion and it had bigger tires. The motors are a bit higher spec then i need but this robot could be used almost everyday of the year for 8 hours if it works. Also it only said max payload of 5lbs which could easily be filled with batteries if i need the 8 hours. Ideally id want brushless motors but cant find any that would suit.
Okey dokes ill go for one of those batteries. Driving really wont be an option im afraid i can always source a bigger capacity one from elsewhere. Yes i could put batteries in parallell but the cost would add up using the NIMH. Was thinking of using Li-Ion Rechargeable Battery Flat-top 3.7V 800mAh and 3 sets in parallell with 4 batteries in series in each pack. But im unsure if these packs have any circuitry inside to prevent over charging or other saftey features.
That kit looks perfect to make a start with thanks for that! I can use that to start with and just make a waterproof seal that will go in the main box with the switches inside.
I could be wrong, but the battery you’ve linked might need a spotwelding machine to make a 4S3P pack. Those battery poles are usually hard to solder without special flux solder. And it’s easy to kill the cell during the soldering.
That’s highly recommended in your case.
Why not use a big 4WD brushless RC-car chassis? Monstertruck for extra size wheels.
It offers all the good things you need, plus a suspension for rough terrain.
The only thing such an RC car can’t do, is turn on the spot
