This ambitious rover project is a childhood dream of mine of building a small Sojourner like rover, fitting it in a rocket, and launching it out into a field where it will survive a couple of nights, or weeks, or however long it'll last. This blog is to document all the lessons learned, occasional failures, and all the fun along the way. To see how this all got started, go to my first post in May 2013.
Sorry for the month and a half long delay but... We're first time homeowners!
We've been busy painting
And doing yard work
We have a nice back yard that has filled in quite a bit since this picture. But I'd like to think there is a rover proving ground in there somewhere.
The shop is coming together. Just need to build a bunch of work benches and acquire a few more tools to make building robots a lot easier.
But since the last post, I haven't just been working on house things. I accepted a position as a Test Engineer at work so loads of training there and I also started work on the new steerable suspension. I spent a lot of time designing the new parts and even managed to print the left side components.
I finally figured out the right combination of settings for printing in ABS without a heated bed or enclosure. No more curling parts pulling off of the bed. A short 'raft' of PVA and then the ABS on top of that, along with proper nozzle height, seems to work great!
This is Inspiration with its new left side suspension. Still unwired and kind of mocked up here but this is the idea. A ton more ground clearance and better turning ability.
And just for kicks, I added a nice background from Inventor's stock background schemes.
That's it so far. I hope to start printing the right side parts this weekend and get it driving around soon. But in order to get it driving around, I need to change out the motor driver for the servo controller which also needs a little programming and also updating the Arduino's program so that it talks to the servo controller. After all of that, I plan on making a new metal detector arm since the current one is too short and will also hit the new front suspension. And then I'd like to change out the camera arm for something that can pan and tilt. Lots of things to do yet but it's coming together.
We also attended our first Tripoli Minnesota rocket launch day last weekend with my nephew Will and met some great people and got some great advice for the up coming rocket that will carry Inspiration out to its eventual landing site. Apparently there is a group of students that are attempting the same idea of launching a rover out into a field. We came late and missed them at the launch though. I'd love to meet them and compare ideas so hopefully they'll be around again.
Well.. stay tuned for more updates and have fun out there!
p.s.
If I could, I would have this SpaceFest timer running on the side of this blog. But for now, you get a link.
Can't wait! Time to SpaceFest VII
Alright I'm back. Slow progress. But that's been kind of the theme of this project since the start. Even though I'm finally done with school, it would appear that other things still fill my time. Currently there have been two other projects going on besides Inspiration. For one, we have been working on becoming homeowners! After looking at several houses, we've finally settled on one and now in the process of purchasing. If all goes well this month, Stray Robotics will be moving from this little work bench:
To this much larger work space with outlets already positioned for the super long work bench that will run the length of the wall and maybe that far wall as well.
The second project that's been taking up my evenings is a Shapeoko 2 cnc router that several of us Anoka Tech students are making. We got the kits, motors, power supplies, and hardware and started assembly a few weeks ago.
The frame as of last week
The stepper motors, motor driver, and power supply
Assembly as of 3/31/15
When I'm not working on those two projects, I try to get things done on Inspiration. Lately my focus has been on the front steering brackets and getting the Pololu Mini Maestro servo controller to do what the Arduino tells it to do. In this video, I have 5 of the 6 total drive servos plugged in and running along with 1 high torque steering servo. This is testing to see if the Maestro can drive all of these servos at once without any problems.
The Maestro performed flawlessly but there seems to be a delay on the Arduino side that I've noticed periodically while driving Inspiration around. For some reason this delay shows up more with the Maestro. I'm willing to bet it has something to do with my pieced together code and the way it looks for an input command from me.
But anyway, after this test, I started on the upper servo bracket. I drew up something to hold the steering servo onto the front suspension arm.
Once I had the bracket drawn up, it was time to send it to the printer. I didn't get video of this one printing but it turned out alright.
Here's a video showing how this bracket works with the wheel.
Just a mock up of how it will replace the current front suspension.
Next up for me will be to print the right front brackets and then try to figure out how to do the rear suspension. My plan is to have this thing steering by this summer, so hopefully I can spend some more time on this once the router is finished. Stay tuned and have fun!
Big things have been going on over here in the past month. Cristin and I (and no part of Stray Robotics) have been accepted into a fantastic and elite group of volunteers, The JPL Solar System Ambassadors. We, as individuals, can now go to schools and public events and discuss topics in Science, Technology, Engineering, and Math (STEM) or anything else JPL might like us to participate in. As an example, Cristin and another ambassador will be talking about Hubble at the Minneapolis Science Museum later in April. I have also taken a new job as an Engineer at a great company, so no more assembly or machine running type work for me. I get to finally put my Bachelor's and new electronics degree to good use! So a little inspirational tip for you timid folk like me, if you see a job you think you'd be good at but feel you don't have the qualifications for, go ahead and apply for it! You might be surprised by the people who interview you and find you have some great things in common. If you're a pleasant person and excited just to be there, they might be willing to train you. And chances are, you'll find people that think you'd be good at it too.
That brings me to the whole point of this project and this blog, which is to inspire everyone to "Go Forth and Be Brilliant", as +Cristin always tells me. What I try to do at the various places we show Inspiration is to inspire people, no matter how old they are, to pursue their dreams. Find that childhood dream that got lost during the course of growing up and go get it! It was your dream for a reason and I'm willing to bet that life will become much more interesting and rewarding once you start on that journey. I could go on about my life changing experiences since pursuing my childhood dream but I think that would be best shared elsewhere. And of course, feel free to share your stories in the comments or message me.
Now lets get back to the progress. We had a great meeting a few weeks ago with Donald (the LabView genius) and he's come up with a great way to retrieve specific information, that I can make constantly streaming from Inspiration, and turn it into wonderful gauges on the control panel. Gauges like battery level, internal temperature, servo positions, and anything else we want to monitor. He also figured out a way to grab the GPS data and use it in a Google Maps window to guide Inspiration to anywhere on the map. Very exciting stuff that is mostly waiting for the parts that I'm working on. Which is:
Steering. After noticing how terrible Inspiration turns on high traction surfaces, I've decided to make the corner wheels turn to make rotation a lot easier. This also makes Donald's GPS guidance system work a lot better since Inspiration won't have to be moving first in order to turn towards a way point. This also gives it about 4 more inches of ground clearance which was desperately needed since Inspiration couldn't even clear small rocks without getting caught on them. (The next Jenga block test with suspension was a miserable failure too and I probably didn't share that video... or even took the video.)
Speaking of videos! Here is a time lapse video of one of the steering brackets being printed on our 3D printer.
This was actually the second attempt because I'm still trying to figure out how to keep the material from peeling off of the bed during a print. The first attempt got about 1/3 of the way and then started to peel up so badly that it popped itself loose. I still have some techniques to learn yet before I print any more parts. But here is the finished bracket with the servos and wheel mounted on it:
I then decided that it was unnecessarily bulky and that it could lose some size and weight and add a little more ground clearance by taking off the useless tray that the drive servo was sitting on. I also shaved off some of the excess material in the middle of the bracket, making it look more streamlined. You can see the bracket changes I've made on this next picture (which, now that I look at it, I could have brought the ground up a little higher so it doesn't look so funny.)
I was also forced to bring the shoulder joints out farther because the drive servos stick out a bit and would hit the body during any kind of suspension movement. So Inspiration now has a wider stance too which could probably come in handy. But it also means that I'll need to make the rocket a little bigger too. So far it looks like the rocket might be about 10 to 12 inches in diameter and that would make it roughly 8 feet tall if I try to keep it in proportion. But that's a much later problem to deal with.
Right now, the focus is on steering and a new suspension that goes with the new brackets. Then the best part, test driving! So stay tuned and share some stories or ask some questions in the comments. And remember to Go Forth and Be Brilliant!
I am finally done with school! Thank you Anoka Tech, Tom Reid, Daniel Truchon, and Curt Barnier for all of the wonderful knowledge I have gained and can now go out and use! It has been a long journey that all started with this rover project two and a half years ago and has finally lead to a very useful A.A.S. Degree, a membership in Phi Theta Kappa, a membership with the American Institute of Aeronautics and Astronautics (AIAA), and volunteer work with AirSpace Minnesota. And you may already know about presenting the rover at SpaceFest VI thanks to a little push from friend and space author Jay Gallentine. These are all things that I have gotten involved with directly because of following the dream of launching a rover into a field. And of course a lot of help from +Cristin Finnigan who showed me how to believe in myself and to go get my dreams.
So school is finally done but I feel like the real fun stuff is just about to begin. I can now devote more time to the rover and this nifty new 3D printer from Zeepro.
Now, if all goes well with this prototype printer, I can start printing better suspension parts for Inspiration and anything else I can think of that it might need as we progress.
I know I want to create something to reinforce the inside of the rover and hold all of the electronics without being too heavy or in the way and also create parts to allow for steering and better ground clearance. So these will be the next parts that I will be working on.
Over the past couple of months I did manage to spend some time working on Inspiration's battery charging system. You'd think the coding for 4 relays would be pretty straight forward and easy but it turned out to be kind of tricky to get around situations that would cause 2 different if statements to be true and make the relays squeal from trying to be open and closed at the same time. It turns out I did actually over think the problem and just had to change some wiring and greatly simplify the code. Oh which reminds me, now that it's winter and the solar panels don't do much, I bought a Variable DC Power Supply to use for the 12volts or 300mA to charge the batteries during my tests. So far it works great and the Arduino shows them slowly charging and discharging while turning 6 continuous servos. So now I just have to simplify my charging circuit and stuff it into the rover.
That's it for now. Hope everyone is having a great holiday season and I'll catch up with you next year!
I just wanted to quick update those who are following along with the progress of Inspiration. Currently I am taking my last 5 classes at Anoka Tech for an A.S. for Electronics Engineering Technician and working full time at night, so rover work has slowed a bit.
I have figured out, however, how I am going to charge a battery with the solar panel and drive off another one and switch between the two on the fly. I purchased a 4 relay module that the Arduino can control so the batteries can be charged separately, used separately for driving, turned off when not in use, and disconnected from the solar panel in the case that both of them are fully charged.
I'm also still working on the conversion to all servos instead of DC motors and 2 servos. This is taking some time because I need to learn how to program the servo controller so that it does the basic driving commands and also talks to the Arduino.
Another thing in the works is Donald is working on the GPS guidance system so that it can use Google Maps to show were Inspiration is and also the desired way-points that it should travel to. Very exciting stuff!
All of us SpaceFest goers have recently found out that SpaceFest VII will be (tentatively) in June of 2016, so that takes a huge load off of this project since I really wanted to have a lander made up for the next time we possibly display at SpaceFest. Now that I don't need to work on a lander, I can stay focused on really making Inspiration the rover it deserves to be.
I should be done with school in mid December so I plan on really taking off with this project by then. So be patient. These next couple of months probably won't have much for updates but soon there will be very exciting things going on again. Aside from finishing Inspiration, there will be a new blog to follow for the lander and all of its complexities, and then another blog for the liquid fueled rocket! I'm sure things will get crazy with that one. So stay tuned and have fun! Also, if anyone is working on a similar project, I'd love to hear from you!
Well I'm finally done with school for the summer. Amazing how an 8 week 5 credit math class could soak up so much of my time! So I apologize for the delay in progress. I now have a lot more time in the mornings so I think I might be able to get some things done before classes start again in late August. I did manage to get out and do the very first long duration drive over the Solstice weekend in June. That was really exciting because I had the sun's full power and a big open parking lot to drive around in.
So with this test I got to see how much power the solar panels were putting out, how long the battery would last, and also got to test the cooling capabilities of one of the micro fans I had purchased a little while ago.
I had a lot of fun just openly traversing this parking lot.
Not much for obstacles but that's ok. I wasn't there to test the suspension.
As you might have noticed, I replaced the metal detector arm with a small fan.
Since I didn't want to cut a hole for the fan just to find out it didn't cool much, I decided to just use the existing hole and the switchable power normally used for the metal detector for this test. I cycled the fan on and off throughout my drive and each time I cycled it off, the internal temperature would climb to around 100F and with the fan on, it would fall to about 95F. Outside temp was around 75F that day. So the one fan test seems to justify cutting a hole in the side for a fan or two.
This video shows what it looks like from my perspective while operating Inspiration.
You can see the single letter commands put in and then getting the action replied back from the rover letting me know that the command was received and executed.
In this picture you can see I came across a small number 5 in the dirt. Too bad I didn't have the metal detector. It would have been fun to sample something that I didn't put down.
(don't mind the battery voltage, I still don't have that hooked up yet.)
Here I was testing the solar panel output and was greatly saddened to see that in full sunlight, it only had a
20 milliAmp draw on it. I'm assuming the battery was providing all of the power to the systems and so this measured power might have been making it's way to the battery or simply taking 20mA's off of the total load on the battery. At any rate, this was never going to charge the battery like I had intended.
So the plan now for battery charging will be to have another battery on board and a small circuit to charge one battery while the other is being used and then be able to switch between the two. This idea came courtesy of fellow student Shawn Doyle who used such circuits during ComSAT communications in the army. So it's gotta work, right? I know simply charging a battery off of the solar panel works pretty well. Oh another flaw in my design was to have an 8 volt regulator in line with the solar panel to battery so I wouldn't risk exploding the battery with the 12 volts from the panel. Well this definitely limits the power from the solar panels and with the way it's wired up, also limits the power from the battery to the systems. So I think with the new charging circuit, I'll have a relay turn off the solar panels when both batteries are at 8 volts that way I'm not limiting the power through a regulator anymore.
And now onto something that I'm very excited about!
This is the new control panel for Inspiration created by fellow student and LabView wiz, Donald Morgan.
He's been working hard on giving all 27ish commands a functional button. And just yesterday I got to watch him integrate the video feed from the rover and also information sent back, into the sidebar. Really amazing work! This is going to change everything when it comes to demonstrations. I might actually feel comfortable letting people drive it now. (ok, maybe after I add steerable wheels so it doesn't tear itself apart anymore)
Oh, I forgot to mention the results of the long duration drive! Inspiration managed to drive for a total of 45 minutes almost non-stop at top speed before the camera started to get fuzzy. I could have probably turned the camera off and got another 20 minutes out of it but realistically, I won't be able to drive without the camera. Unless it's traveling to a GPS waypoint, then I guess I wouldn't need the camera during that time.
Which reminds me!
I managed to test out the GPS unit the other day. On the balcony, I synced up with 9 satellites and found that my location isn't written in a format that Google maps can use so I need to some how convert it by moving a decimal 2 places to the left and adding a negative to the longitude coordinate. When I did that however, it placed me about 10 miles away. So I guess I have some work to do on that. When I get it figured out, Donald thinks he can get Labview to take the location coordinates and plot a course to the selected waypoint. So technically Labview would be controlling the rover at that point. Which I think is really cool! I'm assuming that should free up the Arduino to keep doing other tasks like monitoring the metal detector, scanning for obstacles with the sonic range finder, and allowing me to move the camera.
Hopefully lots more to come in whats left of my summer break. Stay tuned and have fun!
I know.. it's been a few weeks and I was supposed to go to the Hack Fatory's Minne Maker Faire and then post about it. School and work have kept me a bit busy lately but I can now post a quick bit about what's going on in the world of Inspiration. So +Cristin and I set up a table at the great Minne Maker Faire and showed off Inspiration for all the makers in the area to come and see. Here's some pics of our set up:
Instead of red dirt like we used for SpaceFest, we just grabbed some gravel out of the near by play ground which worked quite well. Lots of people showed up and really enjoyed seeing it moving around and sampling the wrench I had set out for it to detect. Lot's of great ideas and suggestions from people and I managed to write some of them down to pursue later in this project.
But the Maker Faire was awesome! Lot's of great people demonstrating everything from robotics to trebuchets and star trek props (including a functional console and captain's chair!). There's some more pictures from the event located on the Facebook page, https://www.facebook.com/strayrobotics?ref=hl
During the Maker Faire, the room we were in was about 90 degrees so I kept checking the internal temp sensor on Inspiration and found that it got up to 100 degrees inside. I did some quick research on my phone for maximum battery temperature and found a lot of people agreed on 115 degrees before it might burst open. Maybe violently. Sooo.. I set forth on some research for cooling techniques when I got home. One of my favorites was this Peltier Cooler. Actually one smaller but I had no idea this type of technology existed and better yet, in a 1inch square that runs on 5 volts! Problem with that is it also draws around 7 amps which is about 7 amps over budget. So I settled on some fans and found some great 1/2 inch ones to stick in the sides and draw in some cooler outside air. Hopefully it'll work. I'll need to do some tests first before I go cutting holes in the rover but unfortunately I think a lot of this will have to wait until mid July when my math class is over.
Here's a pic of my latest upgrades:
Along with the cooling problem, I also have a ground clearance, turning, and weight problem so I did some more searching for better internal systems. I found some really small Bluetooth transceivers which I hope to replace the XBEE's and their bulky shields. I also think (but not sure yet) that I might be able to send programs to the rover without having to unplug the Arduino from the rover and hook up a USB cable to it. That'll save a lot of time and hassle if that works out. Also for turning, I decided I need the four corner wheels to be steerable so the rover can rotate around easier. I picked up a micro 18 port servo controller so now I should be able to replace the 6 drive motors and camera arm motor with continuous servos and then add 4 servos for steering. This will give me a lot more room inside the rover and create more ground clearance by adding the steering servos to the suspension.
Hopefully I can get to all of this soon. I still need to learn how to program them all, learn to incorporate the ping sensor and gps sensor, draw the new parts, print the new parts, and learn how to put the whole thing to sleep in order to conserve power and charge more rapidly.
