The is a great project! It gets a little “fiddly” at times but it is one that starts with a box of parts on day one finishes with a complete illuminated model on the second day. It’s also dear to me because the high percentage of reused materials. Note in the picture to the left that the display case is also made of reused materials. A Christmas decoration came in the clear drum. The top is a spare sink stopper hot glued to the top. During my first build day, I cleaned and painted the materials. Vinyl decorations were
cut out with a razor blade on plexiglass and applied. The arms were assembled from FireBall mini bottles and automotive air fresheners. I also painted the fabric softener dome top.
On the second day, the LEDs and current limiting resistors are mounted followed by mounting the dome on the top of the can with hot glue.
It made most sense to mount the push button on/off switch and the power socket before mounting the battery holder. Unlike the TARDIS, R2D2 is NOT bigger on the inside and it gets crowded quickly.
The 3 AA battery holder is mounted on a ¾” piece of plywood cut to 2″ square and sanded on one side to fit on
the inside of the soup can. A belt sander makes this particularly easy since it can remove a lot of material quickly. I placed sticky hook and loop fasteners (Velcro) to the battery pack and the mounting platform and hot glued the assembly to the front of the robot. I may want to replace the batteries in the future and having the holder mounted on Velcro will allow me to remove the holder when required.
Having a battery operated R2D2 tin can robot is neat. It allows me to put it anywhere on display independent of the need for a wall socket. However, most of my displayed tin can robots are on a shelf and powered by an external power supply. Honestly, I don’t know where this one is going to end up so I added the capability to operate on an external power supply.
I bought D.C. power sockets and plugs in the past for previous projects, so I knew that they were available—somewhere. After a short search that felt longer than it was, I came up with the socket and plug combination. I also had an Apple USB charger adaptor that someone conveniently left for me on the side of my walking path. Finally, a quick rummage through the “wire box” and I had the needed USB wire. Once again, I had the pleasure of using materials that I had on hand.
This is hard to admit but
wiring this little robot toy is terribly confusing, and it shouldn’t be. There are only a couple of components and a few connections. Even though this was my fourth one, I had to get out my pencil and paper and turn down the radio so that I could concentrate. I’ll include the diagram here but it’s hard to follow. The secret appears to be that the ground connection is the one that is switched. In my experience, it is usually the positive lead that is switched. In this case, the battery positive lead, the socket positive lead, and the LED positive lead are solidly connected without an interrupting switch. The pushbutton switch on the back of R2 interrupts the ground to the LEDs. One end is connected to the LEDs and other end is connected to the socket negative lead. On my socket there was a connection without a wire, a bare connection. I checked with an Ohmmeter and found that when the plug is not in the socket this bare connection and the ground connection are shorted. Once the plug is inserted, the bare connection and the socket ground connection are disconnected, and the ground provided to the LEDs is from the external power supply.
The allows the robot to operate on batteries when the plug is not in the socket. TA DA!


The first step in building the R2D2 tin can robot is collecting a few things. This is my fourth one so I’m familiar with what I need for materials. The one luxury that we have these days is plenty of time. I’m not in a hurry. I have no deadline to meet. I’m going to enjoy every part of the build.
I love CampQuestAZ. It gives me the chance to share the “maker” experience with the young campers. My R2D2 was only an example. They had to come up with their own design made from the parts I brought to camp. Check out the imaginative and creative robots they built!
Unlike their effort, I have a plan and the experience of building 3 previous R2D2s. So during my build today, I skipped around a bit. After collecting all of the necessary materials and tools, I cleaned and painted the can, the dome, the tiny liquor bottles, the air fresheners, and the dental floss container. All of the parts require a multiple coats. The base coat is black.
Next, I painted the can and the dome metallic silver. Finally, I masked a couple of small areas on the can and painted the can and the “arms” an off-white (ivory). The masked areas become the vents on the front of R2.
The blue highlights are made of vinyl tape applied to a piece of plexiglass and cut out using an Exacto blade.
R2 is starting to take shape! All that remains is to add the wiring and electronics. They are amazingly simple. The model uses only 3 LED bulbs, 3 AA batteries, and a switch. Since the LEDs are different colors, each one will require its own current limiting resistor. The blue LED has a forward voltage drop of 2.8 V; the red LED drops 2.0V, and the “Rainbow” LED drops 2.5V. I calculated the resistance values needed to provide 20 mA through each of the LED (assuming a nominal power supply voltage of 4.5 V). The values only have to be in “the neighborhood. I chose an 85 Ohm resistor for the blue LED, a 100 Ohm resistor for the “Rainbow” LED, and a 125 Ohm resistor for the red LED. If you’re interested in how these calculations are done, leave me a comment.
You may recognize this picture. Especially, if you are a long-time reader of this blog. It is a model of the Star Wars robot R2D2. It has LEDs that light up; it is crude. Most importantly, it is something made almost entirely out of recycled materials. The main body is a Healthy Choice soup can. The dome is from the top of a fabric softener bottle. The arms are made of small liquor bottles. The front foot came from my dentist. It had a small amount of dental floss in it originally, and the main feet are automobile deodorizers that I found on the side of the road. There are parts that I had to purchase, however. I used hot glue, two hex head bolts with matching nuts, multiple colors of spray paint, some vinyl tape, light emitting diodes, a few resistors, a battery holder, 3 AA batteries, and a switch.
This is the first one that I built to use as an example for a Camp Quest AZ activity called “Tin Can Robots.” In all I built 5 examples: A Dr. Who Dalek, this R2D2, Rosie the Robot from the Jetsons cartoon show, Rocket Man, and Robby the Robot from the movie Forbidden Planet.
build in the comments. I’ll do my best to be as descriptive as possible, but I may miss a few details that need clarification.
This should be fun. We’ll start tomorrow with cleaning up the parts…
Yes, it’s another unboxing blog. I’m feeling guilty because perhaps I shouldn’t be having so much fun while on lockdown when others aren’t so lucky.
dedicated, serious peddlers that rode past with that scowl that says, “Don’t bother me I’m doing something really important here!” I get that I guess. People are different. I personally enjoy a “howdy do” during these times of isolation but I understand how others may not. What I don’t understand are the bikers that come from behind and pass at break-neck speed as close possible. There have been times when I step off the trail to let large groups go by. I’m a bit reluctant to do that now because we have some non-human company sharing the path these days.
Normally, these guys don’t bother me much, but “The Loop” is rather busy, and they appear to be rather nervous and noisy. They’re easy to spot on the paved path, but their camouflage is very well matched to the desert on each side. They disappear. On the positive side, I think I get more out of my exercise when I hear the rattle. I’m sure my heart rate goes up a bit. Lately, I’ve seeing two or three every day.
. I have to say that this shelf is not universally appreciated but I still get away with it. Just today I picked up the little green bottle sitting between Rosie and R2D2. It came in handy when I needed a small light weight object to move with my new robotic arm.
By the way, I should end this here. I’ve reached 500 words and came full circle. The box of parts in the beginning is now a working robotic arm capable of holding something that I found on my walk. Nanu nanu!
I bought a few robot kits late last year and early this year. I also bought some robot associated kits. For example, I bought a robotic arm driven by hydraulics. I buy these things for evaluation and get ideas for a robotics program at 
Last May, Nancy and I brought home a beautiful new truck—a 2019 Super Cab Ranger 4×4 with the top-of-line trim and all the goodies. A couple of days ago, my “connected” vehicle sent me a message:
Here in Arizona, the governor finally decided to announce a stay at home order. Governor Doug Ducey is just another example of a person who should not be in the office he is holding. When are we going to realize that the best person in administering a government is not a businessman? I’m happy that he can sell ice cream, but I’m not impressed with his performance as a governor.
What a great day we had at the Capitol! Tory Roberg, our Secular Coalition for Arizona lobbyist put on the best secular day ever. The Secular Coalition for Arizona was created in 2010 so this celebration represented 10 years of effort. We have a small budget but energetic volunteers and have been able to “slow the roll” of the religious groups such as the Center for Arizona Policy and the Alliance Defending Freedom as they try and eliminate the separation of church and state. In fact, we got to march around the capitol saying “Separate: Church and State!” while carrying signs. I don’t know if we changed any minds, but I felt good doing it.
If you’re in Arizona Legislature District fourteen we could use a refresh. I haven’t had a chance to meet with Gail Griffin or David Gowan yet. However, I did see State Senator’s rude performance during a secular invocation last year. All three need to find other ways to spend their time and we should help them out by not voting for them during the next election.
A couple of days ago I sat down to write about Martha McSally and what a disappointment she is. On paper she should be a great representative for me. I live in Arizona and I retired as an officer of the U.S. Air Force. However, she’s such an embarrassment that I’d like her to move to another state and stop bragging about her military service.
A lot has happened since my last posting on October 16th. Halloween and the Night Before Halloween happened. It was one of the best! The theme was Aliens from Outer Space. As always, much of the fun was creating the props associated with the theme. What is less fun is finding a place the store them after the event is over. Anyone need a collection of pumpkin
based aliens? I may have to put them on Craig’s List. Right now, they’re hanging around the storage shed and getting in the way every time we visit it.
bit less work than the Halloween party but has a similar number of people. It was held on the 21st of December and started at sunset when we lit the fire in the pit. The party goes on into the night and finishes out a bit after midnight. It’s always a great time. Our ancestors knew that Winter Solstice is the perfect time to have a big celebration. Those in the Northern Hemisphere knew that the days would stop getting shorter and the Sun would hang around longer each day. To celebrate, many lit a celebratory fire right at sundown as we did. Winter Solstice is the end of a solar cycle—the end of the year essentially. It is in the coldest part of the year and the official start of the Winter season.