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JPL Open-Source Rover Project Based on the Rovers on Mars

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Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#61

Post by domtron_vox »

squarefoot wrote: post #49
iwakura wrote: post #45

This is great. But it's a little discouraging to see the project only use the US Customary units considering this is a science project. I was under the impression that NASA used SI.

I think it's aimed at students, schools etc. Its purpose should be to attract people to science so it has to be less intimidating, hence the choices of the Raspberry PI or the phone app or the Xbox gamepad to control it.

In my experience, Xbox controllers are actually fairly common for large robotics. It is relatively cheap to buy a controller and USB wireless dongle plus there are lots of software libraries to help interpret controller input.

My main experience being my participation two years in a row in the Intelligent Ground Vehicle Competition (IGVC). A college competition to develop self-driving rovers and "cars" (golf carts). There were around 40 teams from various colleges (several international, not just usa) and many of the teams used xbox controllers for manual control including my team.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#62

Post by domtron_vox »

elkos wrote: post #60

If you are interested in other open-source space technologies feel free to check out Libre Space Foundation's ( https://libre.space ) code repositories ( https://gitlab.com/librespacefoundation/ ) We aren't NASA or JPL but a non-profit based in Greece. We already run SatNOGS (a network of satellite ground-stations), UPSat (the 1st satellite with components mainly under the CERN Open Hardware License) and on the side…

Been following SatNOGS for a while now. Building on of the ground station designs has been on my to-do list for a while.

Recently checked in on the website and saw the building instructions have gotten better and much clearer.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#63

Post by kgilpin »

Cshelton wrote: post #57
iwakura wrote: post #45

This is great. But it's a little discouraging to see the project only use the US Customary units considering this is a science project. I was under the impression that NASA used SI.

Wasn't the conversion, or lack thereof, the problem with one of the Mars rovers some years back? The one that landed on the surface, rolled off the pad and died. I'm sure someone here knows more details about it, but I remember it being something about the teams not converting correctly/at all between the two systems...

You are thinking of the Mars Climate Orbiter crash:

https://en.wikipedia.org/wiki/Mars_Climate_Orbiter#Cause_of_...

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#64

Post by joshvm »

gabcoh wrote: post #9

This seems really awesome, but my God is it expensive. Maybe I am not reading correctly but it seems like just the nuts and bolts from McMaster cost $230 and that's still excluding the electronics and additional hardware! I guess I'll have to save up a bit before I can play with my own minituare rover. edit: the motors also are going to cost around $500

It's really not too bad. To buy a 4WD all-terrain kit from somewhere like SuperDroid Robots costs around $1500-2000 without any kind of automated control system. That will get you four motors with encoders, batteries chassis, wheels, a good (Roboteq) motor controller and an RC kit.

The one we had at work could easily drive with a large adult (i.e. 80+ kg) sitting on it.

I mention SuperDroid because their chassis are high quality welded aluminium, chain driven wheels etc. They sell to hobbyists (robot wars) and industrial markets including law enforcement.

Most of the markup is on the frame. If you have acess to a welder and something to cut aluminium you could do it a lot more cheaply. And yes, high quality motors with encoders cost $150 each. As always, you can go cheap as a hobbyist and pay with your time.

If you want something semi autonomous you can buy a Clearpath Husky for about $20k.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#65

Post by iancmceachern »

AYBABTME wrote: post #23
ummonk wrote: post #16

Earlier quoted context omitted.

McMaster is extremely overpriced. Good for just ordering stuff for quick prototypes where you don't need to shop on price, but otherwise, it's easy to end up paying multiple times as much for some item as you would if you found a good OEM supplier for each component (and this isn't even considering Chinese OEM suppliers).

I just recently learned about McMaster and noticed it's overpriced, but I don't know where else one would get all this variety of equipment. Where can I find such OEM suppliers?

Plus they have CAD models of nearly all their products. It's saved me hundreds of hours over the years.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#66

Post by aweiland »

gabcoh wrote: post #9

This seems really awesome, but my God is it expensive. Maybe I am not reading correctly but it seems like just the nuts and bolts from McMaster cost $230 and that's still excluding the electronics and additional hardware! I guess I'll have to save up a bit before I can play with my own minituare rover. edit: the motors also are going to cost around $500

This was my reaction as well, however I do appreciate the reasons for the expense. I'm curious if a "lite" version of this could be made for home hobbyist tinkering.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#67

Post by squarefoot »

_verandaguy wrote: post #56
squarefoot wrote: post #49

Earlier quoted context omitted.

I think it's aimed at students, schools etc. Its purpose should be to attract people to science so it has to be less intimidating, hence the choices of the Raspberry PI or the phone app or the Xbox gamepad to control it.

It's a weird world where kids are more scared of the metric system than they are of a credit card-sized Linux computer with its guts showing.

It probably is just a matter of being used to it. In the EU we are used to the metric system, but are ok with screen or hard disk sizes expressed in inches to the point if some brand advertising offered a 1.5 meter wide screen TV most of us would look for a calculator to make the conversion, including myself. If we changed to the metric system also for TV sizes, most people would find it uncomfortable at first, but probably would adapt in months.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#68

Post by regorlas »

aweiland wrote: post #66
gabcoh wrote: post #9

This seems really awesome, but my God is it expensive. Maybe I am not reading correctly but it seems like just the nuts and bolts from McMaster cost $230 and that's still excluding the electronics and additional hardware! I guess I'll have to save up a bit before I can play with my own minituare rover. edit: the motors also are going to cost around $500

This was my reaction as well, however I do appreciate the reasons for the expense. I'm curious if a "lite" version of this could be made for home hobbyist tinkering.

I agree a "lite" version for home hobbyist tinkering would be fun, here's my effort to make one: https://github.com/Roger-random/Sawppy_Rover

I'm sure there are many other versions, created by rover-loving hobbyists around the world.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#69

Post by 0xffff2 »

iwakura wrote: post #45

This is great. But it's a little discouraging to see the project only use the US Customary units considering this is a science project. I was under the impression that NASA used SI.

>I was under the impression that NASA used SI.

NASA is a very large organization with thousands of different projects ongoing at any given time. For many smaller projects like this, it's really up to the whim of the project lead what unit system is used.

Re: JPL Open-Source Rover Project Based on the Rovers on Mars

#70

Post by tomp »

elkos wrote: post #60

If you are interested in other open-source space technologies feel free to check out Libre Space Foundation's ( https://libre.space ) code repositories ( https://gitlab.com/librespacefoundation/ ) We aren't NASA or JPL but a non-profit based in Greece. We already run SatNOGS (a network of satellite ground-stations), UPSat (the 1st satellite with components mainly under the CERN Open Hardware License) and on the side…

Awesome! Can I contribute? In other words, how can I, as an experienced backend developer (Java, Python, Scala, Ocaml, some C/C++) but a complete newbie in space, hardware and/or realtime systems, contribute?
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