CJ a Sawppy variant

When I started building the toolhead, I scoured the internet for detailed pictures showing the toolhead on the Curiosity Rover. The pictures show a quite intricate device that has 5 different tools and the head can be rotated to allow any of the tools to do it's job. As I looked for ways to design the tool for 3D printing, I decided to print each tool seperately and then combine them into one toolhead. Of course, this is the way the real toolhead was built, so that made sense. 

What I came up with was printing a 5 sided frame and attaching each tool to the frame. Once each tool is attached, a top and bottom piece are screwed together to provide a mount to attach the head to the arm. Each tool is made up of multiple printed parts, 14 in total, which allow for printing without supports and easier detail painting.

I added a tool arm that mimics the tool arm on the real Curiosity Rover. This video demonstrates the arm movement. The arm has 5 LX-16 servos and all parts are 3D printed.

The tool head has 5 tools

• Powder Acquisition Drill System
• Alpha Particle X-ray Spectrometer (APXS)
• Mars Hand Lens Imager (MAHLI)
• Dust Removal Tool (DRT)
• Collection and Handling for In-situ Rock Analysis (CHIMRA)

I designed and printed each tool seperately, painted them, and assembled into a complete head. The head can be rotated to present each tool as needed.

This is a little late, but on Halloween, CJ went trick-or-treating. I replaced the tool head on the arm with a pumpkin bucket, dress CJ as a bumblebee, and added a sound file that said "trick-or-treat". In this picture, CJ is with a smaller BeeBot friend.

I drove CJ around my office, entered cubicles,  extended the arm, and CJ said "trick-or-treat". He was able to collect some Halloween candy, but I didn't let him eat it :) 

In the evening, CJ handed out candy to the kids, by driving out to the driveway to meet them and extending his arm. The kids would take the candy from the bucket.

This was my favorite Halloween.

This year, I may have to do it this way again because of social distancing.

Updated Tool Arm

Added robotic manipulator arm and tool package.

As of this date, CJ has attended 5 Contra Costa County Library Exploration Station activites. At each event, our routine has changed and become much more relaxed.  This log will give some of the hilights of each event.

Event #1 - San Ramon, California
	At the first event in San Ramon, we kept the audience behind barriers (small wooden toy blocks) because I was concerned about the durability of the build. We demonstrated CJ's rocker-bogie system by climbing over small obstacles, and entertained by doing 'donuts' in our space.      It was actually good that we kept this first event in demonstration mode though, because there was a power problem and the router would drop the connection. If this happened while CJ was moving, CJ would continue to move in the same direction and speed until either the connection could be reestablished or I was able to get to the power button. CJ literally climbed the walls a couple of times.
Event #2 - San Pablo, California
	Our second event started in a barricaded area, but since there were fewer people attending, we found that many visitors weren't coming to our area. So, we decided to wander the library. This brought much more interaction. At this point CJ had a working camera and we carried a small laptop so that people could see what CJ was seeing.    About 90 minutes into the 2 hour event, I learned a new lesson, charge the batteries before each event, even though you think they hadn't been used much since the last charge.
Event #3 - El Cerrito, California
	We didn't bother with a barricade at this event. We did have a small area where we set out blocks to demonstrate the rocker-bogie system, but soon started wandering the library and the outside events. In the library, CJ found a book about himself. At this event we started letting some of the kids drive CJ. This worked well except the area was pretty congested and CJ was blocking the walkways at times.
Event #4 - Concord, California
	This event was in the evening, so we headed outside almost immediately. It's hard to drive in full sun, but it the evening, it was much easier to see the screen. Once outside and in a more open space, we were able to let the kids drive a lot more.     I had added sound to the program which allowed us to play small clips from movies such as Star Wars, Short Circuit, and 2001. The sounds have been a lot of fun to program and test, but the reality is that at an event, there is too much background noise to hear the sounds from CJ. I am working on ways to make them a little louder though.    One fun thing we did at this event was doing donuts on the moon.
Event #5 - Pittsburg, California
	CJ spent some time with Astronaut Dan Bursch before heading outside to entertain. Most of the 2 hours were spent with the kids and their parents driving as well as climbing over obstacles. It was a fun day and I think we are finally confident with how to approach these events. The electronics seem solid and even though a little girl grabbed the camera and tried to twist it off, no damage was done.      I also added a display at the front so you can see what CJ sees with his camera.  It is just an old Galaxy Note that is running a kiosk app to show the camera feed.
Event #6 - Brentwood, California
	The last Exploration Station event will be at Brentwood Library on July 25 from 2-4. I'' update this section after the event.

Cj has attended 3 Exploration Station events so far and has met several celebrities.

Stomper

Darth Vader

The Star Wars Gang

More Star Wars

Gerald McKeegan (Astronomer and Media contact at Chabot Space and Science Center)

Laura McKeegan (CJ's Mom and maker)

I started building CJ when the library I work for, Contra Costa County Library, decided to have a space theme for the summer reading program and planned 6 events called Exploration Stations. I committed to building a Mars Rover model and bringing it to each of the events. This was in March 2019. I was lucky enough to find Roger's Sawppy the Rover project and spent many hours researching and building my own rover, CJ. My goal was to build a working model based on Roger's projects and then continue to make changes to make CJ more resemble Curiosity, and hopefully add additional features. 

As people have heard of CJ, we have had additional requests for events and I hope to share them here as they are scheduled.

Currently, CJ has a

• mast with a 'working' ChemCam (works as a webcam)
• RTG that contains the control panel for all of the electronics
• UHF antenna
• Sundial
• High-Gain antenna
• Accurate leg medallions

CJ finds a book at the El Cerrito Library!

It turns out that the threaded inserts that I purchased for securing the LX-16A - Coupler to the drive shaft did not work very well. I suspect, because of the direction of the groves.

To fix this, I decided to change the design of the LX-16A - Coupler and several other parts that used the inserts. I am very happy with my new design and find that I can really tighten the setscrew, as well as it being cheaper.

Basically the new design puts a slot in the part that will hold an M3 nut.  I also keyed the hole so that the part is tight on the shaft, reducing the work of the setscrew. This new design is working very well.

I made the same changes to the steering knuckles. 

At the same time, I created a channel to hold the wiring harness, just to clean things up visually.

This is a picture of my wiring harness. I spent a lot of time putting this together, and am very proud of it. I used Techflex 1/8 Inch PET Expandable Braided Sleeving and shrink tubing to keep the wires neat.