Saturday, July 24, 2021

Foot Shell Repairs

R2 sustained some minor damage to his PVC footshells at this past Wednesday's Dodger game, so I finally got around to the repairs today. I had left him in the Droidmobile, in order to use the crane to pick him up so I could remove his right foot to remove the foot shell.



I was actually responsible for some of this damage. It's hard to tell from the picture, but an entire strip is missing from the bottom of the shell (which is actually on top in the picture below), because I accidentally spun R2 around into my foot as we were quickly leaving the center field plaza area to make our way to the media room. In the process, a strip snapped off, so I collected it so I could glue it back. I'm not sure if I was responsible for the other cracks, or if I had some help from the hundreds of fans that were taking pictures with R2, but everything got glued back together.



The left foot shell's door also sustained some minor damage, as one of the two nails and pivot sticks went missing. I think someone got their foot caught under R2's left foot shell as they were getting their picture taken, and when they went to step away, they snagged their foot under the shell and caused the door to jam into the door frame, and the piece got pried off and lost. Luckily, it's very easy to replicate. Just a small PVC stick and a nail that needs to be cut to size.



I didn't take a picture of the results, but it's pretty much as good-as-14-years-old.

Wednesday, July 21, 2021

Star Wars Night at Dodger Stadium - 2021

After a year away from baseball, tonight R2 and I got to return to Dodger Stadium for Star Wars Night.



I arrived with my friend and former roommate Manny (who helped with photos) around 3:15pm for a scheduled 3:30pm call time, and unloaded the droid.



As the other characters were changing into costume, I took the opportunity to admire the trophy case from the 2020 World Series, and take a look at the field.



Once everyone was in costume, we posed for pictures with staff (and ourselves).



Next, we went over logistics with our point of contact, Rena. R2 and some of the troopers were to be stationed at the new center field plaza, behind the outfield wall. Unfortunately, none of the characters were allowed on the field, owing to Covid precautions.



We made our way to our station, taking new pathways and an elevator that didn't exist when we last were here.



Once we arrived and the gates opened, it was pictures, pictures, pictures!



After that, we did a couple of shots for the pre-game TV broadcast.



Finally (or so we thought), we helped out with the "It's Time for Dodger Baseball" announcement, where they pick some fans to announce the start of the game. We were located inches from the center field warning track.



But we weren't done after all. We got a nice surprise when we were told Dodger star pitcher Clayton Kershaw and his family wanted to meet some of the characters before game time, so we made our way around the stadium to get to the clubhouse area and media room behind home plate to meet them. So that was pretty cool.



Finally, Manny and I took our comp'd seats (which were way up high, but the price was right). It was Orel-Wan-Kenobi bobblehead night, as former pitcher and now-broadcaster Orel Hershiser got his own bobblehead. He greeted the crowd in his Jedi robes.



Well, R2's good luck didn't hold out tonight. The Dodgers blew a save to the Giants in the 9th inning, and R2's record fell to 9-3. Oh well. I hope we'll be back next year and R2 can get his record back on track.

Monday, July 05, 2021

Calibrated Sabertooth 2x32 Speed Controller, New Voltage Regulator for Senna Switch 15 on Droid #1

Droid #1 got a little bit of needed attention today. First, I finally got around to calibrating the Sabertooth 2x32 speed controller with the new transmitter (as explained in this post).



Next, I wanted to address a potential concern with powering the Senna Switch 15 box from the Futaba 14SG transmitter. As also mentioned in in this post, the voltage regulator in the Senna Switch 15 box accepts input voltages in the range of 6-28 volts, and outputs 3.3 volts to the box's electronics. Because the new Futaba 14SG transmitter nominally runs on 6 volts (the transmitter itself can run down to 3.9 volts before turning off), as the voltage drops over time, it's possible the Switch 15 would no longer function.

The solution was to find a pin-compatible voltage regulator that can handle a lower voltage range. I found one in the Pololu S7V8F3 voltage regulator. This regulator can take an input range of 2.7 volts to 11.8 volts, and output 3.3 volts (supplying anywhere from 500ma to 1 amp), so this fits the bill. (Note that I'm not using the Shutdown pin; it can and will be left disconnected.) This voltage regulator would even work with the Futaba 10CAG radio. Fully charged, I've never seen its battery (9.6v nominal) above 11.2 volts, so it fits in the range supported by the Pololu voltage regulator.



While I could certainly do the transplant myself, I am on vacation this week and was looking for reason to visit Mike Senna, so I went over to his place for this operation.

The black cubic part underneath the red wires needs to be removed, that's the original voltage regulator that takes a minimum of 6 volts.



Mike removed that part, and soldered in the Pololu part.



All's good! Now I shouldn't have to worry about suddenly not being able to play sounds or perform other functions as the battery discharges with use at events.

Saturday, July 03, 2021

Visit for Robotics Kids

Today R2 and I visited my CFA's office so we could talk robotics with some young students that are interested in the subject.



Along with a presentation that showed how R2 is built, we did a little interactive programming to get R2 to wave a small flag. It is the day before Independence Day in the US after all.



As a thank-you, I was kindly given a Mandalorian Lego set.



It was good to get R2 out again, appearances have been very few and far between.

Monday, June 28, 2021

Finished Installing Dome Speed Controller on Droid #1

Today I was able to finish getting the Sabertooth 2x12RC speed controller installed on droid #1. I needed some 1/2" nylon stand-offs to ensure good ventilation under the speed controller, so with those in hand, I used some 3/4" #4 wood screws to finish the installation.



Next, I calibrated the speed controller with my transmitter. Setting DIP swithes 5 and 6 on the 2x12RC allows the controller to be trained on the minimum, neutral, and maximum values for the joystick settings, and those setting can be saved.

Only channel 4 is needed for dome rotation. The model name "2x12RC" indicates it is a 2-channel, 12 amp Remote Control speed controller. I've found that if I leave the second channel disconnected from the receiver, the dome tends to drift and the controller supplies a very small amount of voltage to the dome motor (under one volt). So little voltage is supplied, that the motor doesn't actually turn; instead it simulates a stall condition, causing the speed controller, wiring and motor to get pretty hot.

I found that if I attach the second channel from the speed controller to an unused channel on the receiver, AND if I disable the corresponding channel on the transmitter, then this problem goes away completely. In this case, I attached the second channel from the speed controller to channel 3 on the receiver, and then disabled channel 3 on the Futaba 14SG transmitter.

In the case of droid #2, I'm using the Futaba 10CAG transmitter, which doesn't allow channel 3 to be disabled, so I had to use channel 5 on the receiver and disable that channel on the transmitter.

Saturday, June 26, 2021

Installed New Dome Speed Controller on Droid #1

After 14 years of fine service, I decided it was time to retire my poor-man's dome controller on droid #1. That controller worked by having a servo horn directly bump snap switches. The wiring allowed the dome motor to turn full speed in one direction or the other (or not at all), but there was no variable-speed capability. The Dimension Engineering Sabertooth 2x12RC will handle that duty now.



Thank you old dome controller, you served me well.



The Sabertooth 2x12RC can output 5 volts to the receiver, but I already have a switching battery elimination circuit powering my receiver (and capable of supplying more amperage), so I disconnected the positive and negative voltage lines from the connectors going to the receiver, and applied some shrink tubing to the metal ends. The yellow signal pin stays in the plastic connector.



I started to install the speed controller on droid #1. It will go over the hole that accommodated the servo motor on the old dome controller. While I think this hole would probably provide sufficient ventilation, I decided that I wanted to put the speed controller on stand-offs just to be sure. So I need another day to get those set up.

Sorry to leave you hanging, 2x12RC. Not for long.

Sunday, June 13, 2021

Attached Senna Switch 15 to New Transmitter

Today I got around to attaching the Senna Switch 15 box to the bottom of droid #1's new Futaba 14SG transmitter. This just required a mating piece of Vecro.



I need to route the connector and cable so it doesn't get underneath the transmitter when I lay it face-up on a table. For now I'll just use blue painter's tape, but in the long run I'll probably glue the plastic connector to the PVC case.

Saturday, June 12, 2021

Speed Controller Adjustments for Droid #2, Power for Switch 15 for Droid #1

With droid #2 inheriting droid #1's transmitter/receiver, I needed to recalibrate the Sabertooth 2x32 speed controller settings to match those sent by the 10CAG transmitter. I never did calibrate this transmitter with the Sabertooth 2x32 speed controller on droid #1, instead using trim values to make adjustments. With Dimension Engineering's DEScribe software, I can tune the speed controller so that its expected min/neutral/max servo pulse settings match what the transmitter is sending, and zero-out those trim values once and for all.



Nominally, the minimum servo pulse setting should be 1 millisecond, the neutral/idle position should be 1.5 milliseconds, and the maximum servo pulse setting should be 2 milliseconds. Using the DEScribe software and the associated Device Monitor application, I can see that these values sent by my transmitter for the steering and throttle channels are actually a bit outside those values. I jotted down what the Device Monitor application reported for each of those settings, and used DEScribe to program them as the expected values. (This will be need to be done for droid #1 and its new radio as well.)



Next, I worked on getting power to Mike Senna's Switch 15 box for droid #2. The electronics in this box run on 3.3 volts. There's a voltage regulator in the box that can downstep 6-28 volts to 3.3 volts. The trainer port in the back of the Futaba trasmitters provides power on the middle two of its six pins (negative on the center-top pin, positive on the center bottom pin). In the case of the Futaba 10CAG transmitter, 9.6v are supplied on these pins when the transmitter is turned on. I purchased some connectors for the trainer port a while back, so I grabbed my last spare and soldered it up.



Good to go, for droid #2 at least. I actually already had this set up for droid #2, but the trainer port on the new Futaba 14SG transmitter was somewhat finicky in accepting the old connector cable I made for droid #1, so I transferred the cable for droid #2 to droid #1, and made this new cable for droid #2.

Also note that since the new Futaba 14SG transmitter for droid #1 runs on a nominal 6.0 volts, and that's the minimum that the voltage regulator in the Switch 15 box is rated for, I plan to replace that regulator with one that matches the 14SG's voltage.

Thursday, June 10, 2021

Installed New Receiver in Droid #1

Today I installed the new Futaba R7008SB receiver on droid #1, to go along with the new 14SG transmitter. This meant pulling out the old R6014HS receiver.



For whatever reason, I use Velcro to mount my receivers, so the new receiver needed some Velcro applied to the back.

And, in it goes. Its footprint is somewhat smaller that its predecessor's. (I wrote "predecessor" because I was too lazy to retype R7008SB. Except I just typed that, and more. Plus, predecessor has more characters than R7008SB.)



Likewise, I swapped out the old R6008HS receiver (that does not support fail-safe settings on all channels) on the electronics panel on droid #2. That receiver will go into retirement. I swapped in the "predecessor" from droid #1.

I still need to attach Mike Senna's Switch 15 box that I use to trigger sounds and other functions on droid #1. This gets Velcroed to the bottom of the transmitter. The battery cover is on the bottom of the transmitter as well, but that's ok. I will simply slide the Switch 15 box to remove the battery cover.

Just a bit more work to do.