We had a great time at Chicago Tardis 2013 All the guests were great.
The blue light under Mini me worked great the effect was just stunning. The motors all held out and he could turn on a dime
The convention was sold out and because of this Mini-me chose to stay in his room on Friday and Saturday the crowds were just too much, but there is something about the saying “less is more” and on Sunday he drew big crowds and the attention of that annoying dog!
My thanks to Mr Dean who took some great pictures of Mini me and sent me links and use them on my blog (sorry it took so long to post them).
A lot has happened in the last 6 months and so I am going to add some posts to catch up.
Starting where I left off November 2013 I went to Reversed Polarity convention.
Besides Mini Me there were lots of other great props and models
I was backing up the other day and found these photos. In no particular order.
Got back from Chicago Tardis a couple of days ago. I had a great time. I took Mini-Me and he trundled up and down the hallway again like last year.
Most people were happy to see him and took the opportunity to get their sonic screwdrivers out. (Ha like that really has an effect on Daleks).
Last year it was obvious that he moved rather slowly and while he was cute and everything, he was also very s-l-o-w.
This year I chose to “update” his motor control by changing the gear ratio on the VEX chassis that I made for last year. I changed it from being high torque to more speed. I learned an important lesson. High torque works better on carpet especially when you want to turn.
If I were to make an upgrade to the VEX chassis for next year, I would add floating wheels for the front. I did not realize that having four fixed wheels does not mix well with low torque. I did not realize that it was more of a fluke that he could turn on a dime last year and due to the higher torque.
There were many amazing costumes and though I did not have a camera with me at all times, I managed to get a few pictures.
So we went on the road trip. I was not allowed to drive because I cannot see above the steering wheel and press the gas pedal at the same time. Also I have been accused of aggressive driving. We arrived in Chicago just after noon on Friday. I hovered down and got my badge, suddenly I was surrounded by the local talent all taking photos and wanting to be around me.
I got quite a fan girl gathering, the girl Daleks started fighting each other for my affection. To be honest it was hard to shake these youngsters off but they made me pose for this photo.
I went in search of some more macho Daleks to hang out with and I found my cousin from the other side of the family (the side we don’t talk about much). He wanted to take me out for a night out on the town.
But we bumped into this Time Lord that would not let us pass.
I left Sec and went off on my own.
Later in line for autographs this annoying dog kept pestering me about his master.
We just got back from a road trip to Chicago.
The trip felt short, but really geeky, because we were driving to a science fiction convention listing to podcasts about Linux! (Linux Outlaws – the donation will be in the mail soon.)
We went to the Chicago Tardis convention. One of the big guests of honor was Paul McGann aka the 8th Doctor. He seemed very laid back and thoughtful.
As always, there were long queues for photographs with props people had built.
In the main room there was a TARDIS on display and Daves Dalek Sec. The Dalek was kitted up with practically everything. It actually opened at the front and the shoulders spun 360 degrees. The Dave who built it gave a short talk about it in one of the panels (which was so popular that there were people waiting in the room even before the start of the panel). He had fitted the eye stalk with a camera so it was easier to navigate around. Used in-line skate wheels and the shoulders looked to move quite smoothly. The whole thing was maneuverable by a wheel chair cart. He did a great job.
I like to make things modular, so I created several general purpose modules. The original purpose of this module was to drive a servo motor based on 3 ultrasonic SRF05 inputs.
I made this so I could hook up more inputs then I used for the servos and the ultrasonic sensor
I used a Picaxe because it’s really a microchip PIC with a basic interpreter preloaded. It’s just pennies above the cost of a normal PIC and the ease of use is worth it.
The 3 servos are physically pointing towards the front, to the left and to the right.
Each one is pulsed in turn
The code turns the servo to one of 5 locations. The optimal values for the 5 locations are full left, half left, center, half right and full right.
The speed at which it turns was found via trial and error. The command ‘pulseout’ gives a length of pulse proportional to the location of shaft on the servo motor. Changing the ‘pulseout’ value in increments of 5, 10, 50 and the pause time, gives the movement speed. A minus step speed reverses the direction. One problem you can run into is that the movement is too fast and the servo overshoots one way, then the other, giving an oscillation effect. Servo_pa08 Ultrasonic
I have included an PCB schematic in PDF form
I used Kicad (open source PCB software) to draw the schematic and layout the PCB.
The PCB has traces on both sides. With some extra effort Kicad can create a 3D view as well as gerbers. Here is the servo board
The three groups of four holes (P1,P2,P3) on the right are for the SRF05 detectors. (connections are power, pulse out, pulse receive and ground)
They feed into the 28 pin Picaxe (U19) on the left.
The three holes immediately above the (U21) 8 pin picaxe connect to the servo motor (J9 connections are signal Power and gnd).
U19 controls the 3 ultrasonic detectors by triggering a pulse and receiving the signal back from each one in order.The 3 numbers are converted from time in uS to the object to a distance number. Then based on the stored numbers the output pins at pin 26,27 and 28 go high or low the number can be 0 to 7. The number represent 5 locations front, left right mid-left and mid-right
In my application U21 scans the inputs available (in2, in3, in4), reads a binary number and jumps to the location suggested by the number. This translates the inputs to a rotational position turning the servo to the left or right. When it has finished moving the servo it rescans the three inputs, and makes the servo rotate based on the next set of numbers.