Hello again!
After a long and busy summer, I've managed to post another blog update. Said update, however, is on the Stray Robotics website. This will probably be my last post on Blogger. From now on, all of my blog posts will be here: The Stray Robotics website
Currently the site isn't much but hopefully that will change this winter. See you over at the website and remember to get out there, have fun, and make something!
Tuesday, November 7, 2017
Tuesday, June 6, 2017
Busy Summer
The past couple of months have been pretty busy for Inspiration. 2 almost back to back weekends demonstrating as JPL Solar System Ambassadors at the Science Museum of Minnesota and then at a YMCA in Wisconsin. Very fun and exciting opportunities! I even decided to start letting kids drive Inspiration around on the table! Really scary at first but most of the kids surprised me with how quickly they figured out the controls and understood how the commands were being processed by the micro controller. A few others seemed hell bent on destroying it. For the most part, though, it was pretty fun and I really enjoyed watching kids light up when they recognized how the code worked that was coming up on the screen while they sent commands to the rover.
Here's some pics from those events. If you recognize your child (or yourself) and would like the picture removed or credit for the pic, just let me know.
Once the demonstrations were done, I decided to look into how the battery was being charged by the solar panel. I quickly realized that it wasn't. The solar panel is capable of about 200 to 300 mAhs. Just sitting there, the rover draws about 200. So the solar panel really wasn't doing much. The nice thing is though, that Inspiration can sit for about 4 hours before dying.
I decided to go back to the 2 battery system where the rover drives on one battery while charging the other and then switching as one battery is drained and the other is charged. Theoretically it should keep Inspiration running as long as there are sunny days. However, I found out the code for such a change over can be tricky. Also, the discharging battery drains faster than the other can be charged so there ultimately the rover would be dead after about 24 hours.
Here are some tests that I did while at work a few weeks ago. I was trying to get the code right and also collect data on how long it takes to charge and discharge.
After these tests I decided redesign the power distribution system and get a few new things to help with better charging capabilities.
A new relay. This relay uses a lot less power to actuate the switches and each relay can switch 2 circuits at once. This should work well for the 2 battery system.
That's about it so far. I will try to post more after Spacefest and show you guys what it was like. If you've never been, I highly recommend it! Stay tuned and have fun!
Here's some pics from those events. If you recognize your child (or yourself) and would like the picture removed or credit for the pic, just let me know.
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| This girl was amazing! She totally understood what was going on and probably knows more about code than I do. She lit up when she saw the code and immediately grabbed her friend who she started talking in Spanish to about it. I was super impressed and would love to know where this kid goes in life. |
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| This was one of the first kids that I let drive. 3 years of really hard work in the hands of a young boy. I may look calm, but inside I was freaking out. He did a great job though and my nervousness quickly went away when it only took him a few button presses to figure it out. I would love to let more kids like him drive. |
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| Inspiration meets Curiosity. Thanks to the JPL Spacecraft 3D app, you can do augmented reality with JPL spacecraft. |
Once the demonstrations were done, I decided to look into how the battery was being charged by the solar panel. I quickly realized that it wasn't. The solar panel is capable of about 200 to 300 mAhs. Just sitting there, the rover draws about 200. So the solar panel really wasn't doing much. The nice thing is though, that Inspiration can sit for about 4 hours before dying.
I decided to go back to the 2 battery system where the rover drives on one battery while charging the other and then switching as one battery is drained and the other is charged. Theoretically it should keep Inspiration running as long as there are sunny days. However, I found out the code for such a change over can be tricky. Also, the discharging battery drains faster than the other can be charged so there ultimately the rover would be dead after about 24 hours.
Here are some tests that I did while at work a few weeks ago. I was trying to get the code right and also collect data on how long it takes to charge and discharge.
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| This was the setup I had going outside of work and I monitored the battery voltages from my desk |
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| Unfortunately the sun wasn't out all week so I had improvise with this setup under my desk. |
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| First test showed one battery powering the Arduino and Xbee shield and the other being charged. |
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| This test showed what happened in my code when the 2 batteries became equal in voltage. |
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| This was a successful test of the batteries charging and discharging. |
After these tests I decided redesign the power distribution system and get a few new things to help with better charging capabilities.
A new relay. This relay uses a lot less power to actuate the switches and each relay can switch 2 circuits at once. This should work well for the 2 battery system.
To manage the power system I decided to get an "Arduino" Nano V3. This little guy will stay on all the time and be able to monitor the batteries, solar panel, and communications so that it can properly distribute power. It will be running the code for charging and discharging. It will also be able to turn off the rover at night or in low power situations. It sips power so having it on all night shouldn't be a problem.
A few other changes I made were to move the camera up front and change how the metal detector arm works. Here is the final product of that change:
After all of this weight got moved to the front, I needed a counter weight in the back so I printed a battery holder for the back. I think it actually makes the rover look better now.
Now the current situation is that Inspiration will be traveling with us to Tucson for Spacefest VIII. So once I got all of the changes made, I had to make a box and ship it.
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| Inspiration in its "Launch" configuration |
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| Made a foamcore box to put it in for shipping. |
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| And the final package complete with duck tape handles and ready to be stuffed in another box and shipped. |
Monday, April 10, 2017
Parts List
In this blog post, I've decided to do something that feels a little personal but probably useful to anyone building their own rover project. It is a (mostly) complete parts list a long with current prices and where I got them. This list doesn't include all of the parts I tried and ultimately didn't use. This is just a list of what is currently on Inspiration. The Amazon links are my affiliate links so if you end up ordering something from the Amazon links, I'll get a small commission (at no cost to you of course). The other links are just simple links to those pages. The link for the Radio Shack solar panels is broken. I can't find them anywhere on the internet so I couldn't update the link.
This post is to show (mostly) what all has gone into this project and how quickly parts add up. This was supposed to be a simple and cheap project but as the years have gone by, new, smaller, and more capable products have come out so I've crammed as much stuff into this rover as I can without it getting too big and heavy (I still want to launch this thing ya know).
After many tests outside, the rover has grown in size to accommodate hills, rocks, and anything else in its way. It's still growing actually. I'm in the process of finally adding the ability to tilt the camera up and down as well as giving the metal detector more reach. I also plan on going back to the 2 battery system and have an Arduino Teensy serve as the brains of the power distribution system. That way the main system can be off at night or for efficient charging while the power sipping Teensy monitors sunlight and properly distributes power.
So enjoy the grocery list and I really hope it helps for anyone out there working on their own rover project. Feel free to leave a comment if you know of something better that I should be using or struggles you may have had with something. I'd love to hear how your projects are going!
If you haven't already, follow along on Facebook, Twitter, and the website www.StrayRobotics.com (which needs work).
| Parts | Price | Quantity | Total | |
| Amazon orders | ||||
| Motor Driver | $5.50 | 1 | $5.50 | |
| Temp. Sensor | $6.79 | 1 | $6.79 | |
| Darlington Transisters | $8.27 | 1 | $8.27 | |
| Metal Detector Pinpointer | $35.39 | 1 | $35.39 | |
| Arduino Mega | $27.24 | 1 | $27.24 | |
| GPS | $17.66 | 1 | $17.66 | |
| Relays | $7.99 | 1 | $7.99 | |
| 5/32 tubing | $6.09 | 1 | $6.09 | |
| Sonic Range Finder | $6.95 | 1 | $6.95 | |
| sub-micro servo | $14.70 | 1 | $14.70 | |
| Battery Charger | $21.95 | 1 | $21.95 | |
| Li-Ion Battery | $19.99 | 2 | $39.98 | |
| Pololu | ||||
| 5V Regulator | $10.95 | 2 | $21.90 | |
| motors | $17.95 | 6 | $107.70 | |
| Motor Brackets | $4.95 | 6 | $29.70 | |
| Motor to Wheel Adaptors | $3.95 | 3 | $11.85 | |
| Sparkfun | ||||
| XBee Kit | $95.95 | 1 | $95.95 | |
| Hobby Wireless | ||||
| Wireless video system | $35.99 | 1 | $35.99 | |
| Wireless camera | $26.99 | 1 | $26.99 | |
| Radio Shack | ||||
| 6v Solar panel | $21.99 | 2 | $43.98 | |
| McMaster -Carr | ||||
| 3/8" Aluminum tubing | $18.30 | 1 | $18.30 | |
| 1 pack of Retaining rings | $10.77 | 1 | $10.77 | |
| Ace Hardware | ||||
| Snap Ring Pliers | $15.99 | 1 | $15.99 | |
| 24x36x1/8 Acrylic sheet | $25.99 | 1 | $25.99 | |
| King Kong Hobby | ||||
| Ultra Plugs | $3.19 | 3 | $9.57 | |
| Wheels | $29.99 | 3 | $89.97 | |
| High Torque Servos | $34.99 | 4 | $139.96 | |
| RC Transmitter/Reciever | $229.99 | 1 | $229.99 | Optional |
| Shapeways | ||||
| 3D Printed Parts (estimated) | $150.00 | 1 | $150.00 | |
Friday, January 20, 2017
New Year. New Post
It's a new year! Holidays are over and life is finding weekends to fill. I have to admit, I've been taking some time off from rover things. I think the winter season has left me uninspired and not really motivated to make drastic changes on Inspiration. It seems like every year I come up with a better way to power the rover or a better way to have the steering and suspension work. This year is no different and I just haven't been motivated enough to start the large amount of work that I want to accomplish.
I did some tests before the sun went away for the winter and found that 1 battery just isn't going to work. Problem is you can either drive during the day or charge during the day. You can't do both. Even just sitting idle uses up all of the power from the solar panel. The rover would have to sleep during the day in order to charge itself. I think having 1 battery charging while the other is used for driving will be the best option. It'll be heavy but so far it's the course of action that is needed if the rover is to be useful to myself during the eventual rocket flight that it was made for or the possible scientists at the Mars Desert Research Station this summer.
It seems the more I try to eliminate wires inside the rover, the more I inevitably put in. Things are getting pretty tight inside the body so there is a chance I may design a bigger one. With this change, I might as well design the camera to mount in the front with a good pan/tilt system on it so a person can actually see the rocks that they are sampling without the whole body getting in the way. I originally designed the camera in the rear so I would get some idea as to how far away something is. Unfortunately when approaching rocks, you can't see them until you notice the sudden jerk of hitting it.
With all of the weight of the camera and metal detector arm up front, I figure I'll have to design in some battery compartments in the rear of the new body to counteract the weight up front. At this point, the rover won't look anything like what I originally started with so should I continue to call it Inspiration? At what point is it a new project?
As you can see, there's a lot to think about and it kind of becomes overwhelming. I'm also trying to spend the winter remodeling the shop before the summer months ultimately compel me to work on the yard and make sure that the house will stand another winter.
Too much to do! Cristin and I would love some help with this whole rover thing. If you have any skills in coding, designing, electrical, arduino, or GUI's and would like to help, just let us know. I started this year thinking it might be possible to assemble kind of a dream team to get this rover officially done this year. I really hope that happens. Unfortunately I can't pay anyone so this team will have to be made up of people who have just as much passion for Mars rovers as I do. I like to think there might be a little magazine article written about us one day. You never know. This rover project has gotten me some pretty awesome experiences so far. I would love to share it with others if I can. Doesn't matter where you are in the world. This project can be added to by anyone. Most of the work that's left now is proper coding, GUI, and some 3D printing. If you think you can help, just let me know. I'd love to hear from you!
www.facebook.com/strayrobotics
twitter @strayrobotics
I did some tests before the sun went away for the winter and found that 1 battery just isn't going to work. Problem is you can either drive during the day or charge during the day. You can't do both. Even just sitting idle uses up all of the power from the solar panel. The rover would have to sleep during the day in order to charge itself. I think having 1 battery charging while the other is used for driving will be the best option. It'll be heavy but so far it's the course of action that is needed if the rover is to be useful to myself during the eventual rocket flight that it was made for or the possible scientists at the Mars Desert Research Station this summer.
It seems the more I try to eliminate wires inside the rover, the more I inevitably put in. Things are getting pretty tight inside the body so there is a chance I may design a bigger one. With this change, I might as well design the camera to mount in the front with a good pan/tilt system on it so a person can actually see the rocks that they are sampling without the whole body getting in the way. I originally designed the camera in the rear so I would get some idea as to how far away something is. Unfortunately when approaching rocks, you can't see them until you notice the sudden jerk of hitting it.
With all of the weight of the camera and metal detector arm up front, I figure I'll have to design in some battery compartments in the rear of the new body to counteract the weight up front. At this point, the rover won't look anything like what I originally started with so should I continue to call it Inspiration? At what point is it a new project?
As you can see, there's a lot to think about and it kind of becomes overwhelming. I'm also trying to spend the winter remodeling the shop before the summer months ultimately compel me to work on the yard and make sure that the house will stand another winter.
Too much to do! Cristin and I would love some help with this whole rover thing. If you have any skills in coding, designing, electrical, arduino, or GUI's and would like to help, just let us know. I started this year thinking it might be possible to assemble kind of a dream team to get this rover officially done this year. I really hope that happens. Unfortunately I can't pay anyone so this team will have to be made up of people who have just as much passion for Mars rovers as I do. I like to think there might be a little magazine article written about us one day. You never know. This rover project has gotten me some pretty awesome experiences so far. I would love to share it with others if I can. Doesn't matter where you are in the world. This project can be added to by anyone. Most of the work that's left now is proper coding, GUI, and some 3D printing. If you think you can help, just let me know. I'd love to hear from you!
www.facebook.com/strayrobotics
twitter @strayrobotics
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