B9 Electronics: The Inside Story Part 2 – Soil Sampler

For those using my version 1 drive section (for robots 300 lbs and under) and you have the B9 Creations soil sampler and are using Eric’s tread sections, this is the only way to install it. There are some modifications that you will need to make to the face plates of the sampler so it will mate correctly with the drive section. Once this simple and easy modification is done it will fit perfectly. If your robot will be over 300 lbs then you will have to go with a more powerful drive section. Since the version 2 drive section has bigger and more powerful motors the existing soil sampler by Mike Joyce will not fit. I could hack up Mike’s existing frame and still use his internals but I decided to design a new soil sampler because Mike no longer offers a soil sampler. I will also add some new capabilities to the soil sampler. Like actually being able to obtain a soil sampler (what a concept). This one will have 2 settings. 1 for indoor “show” use. That setting will allow the sampler tube to come out to the floor, spin and retract like the original. The 2nd setting will actually extend the sampler tube to go below the level of the floor and drill down into the ground. I thought it would be nice for the environmental robot to be capable of actually doing his real/stated job. In order to accomplish this I will be using a 24v power drill motor with clutch. The 2nd setting just extends the sampler an additional 6″. There is also a small suction tube/vent in the drill tube assembly to aerosolize the dirt for analysis.

B9 Electronics: The Inside Story Part 1 – Tread Section

The electronics of a B9 can be as simple or as complicated as you want to make it. To assist me I visitied (several times) http://www.instructables.com/id/Circuit-Building-101 to boost my electronic knowledge and skills. There are a lot of sites like this one but I wouldnt let my fear or lack of knowledge hinder me in getting my robot to do what I want him to do. After all, WHO is the master here? Me or him??
Well, anyway, to facilitate this blog discussion I will be going over various systems in am or will be using in my robot. Because this is usually a touchy and potentially complicated subject I will be dividing it up into several parts. As a single point of reference the RC transmitter and receiver I am using is the Spektrum Dx7 with the AR7000 receiver with fail safes set (at binding) to zero forward velocity, forward hip set to “slump” and contact closure set to announce “Warning, Warning, remote control connection lost”.
DRIVE SECTION
What makes a B9 go? Money….I mean Motors. BIG Motors! See the heading called “New Drive Section” below. Two (2) NPC Br81 and Br82 24v wheel chair motors with Two (2) 6″ 65 durometer rubber wheels for traction and shock absorption. Two (2) Gel Cell 12v 33ah (“Marine” or “Deep Cycle”) batteries, plenty of 10 gauge stranded wire and a Vantec motor controller RDFR23 along with a 24v DC power supply (yes, you can plug him in and drive him around with a really long extension cord if you had to).
I started by wiring the two (2) 12v batteries in series to achieve 24v. You do that by taking the positive of 1 battery and connect it to the negative pole of the OTHER battery. Once that was done, you attach wires to the unused poles of the 2 batteries and connect them to a central, resettable fuse block and distribution panel in the left tread section. [I originally had this area in the hip section but then realized how much of a PIA it would be just to reset a blown fuse (pulling the torso off and resetting the fuse would require at least 2 people probably 3, etc)].
The Vantec controller connects to the RC receiver with 2 servo like connections; 1 marked with a “T” for throttle and another with a “S” for steering. Plug those into the corresponding slots on the receiver and you are ready to learn how to drive your “bucket of bolts”. [As a side note make sure you do not adjust your power curve for forward or reverse throttle. Try it out at its default setting first. You don’t want your “bubble headed booby” popping wheelies or doing somersaults!] The website for the Vantec Manual is this: http://www.vantec.com/RDFR21%20Manual.pdf Take a look at that as it gives you detailed information on how to setup your controller for proper operation. I will also wire in and use one of the switches in the programing bay to turn off the motors for safety reasons and to concerse battery power.
Because the soil sampler will be in the right tread section, you want to take into account that a power feed will need to go to that tread section. Do not forget to put a fuse in line for the soil sampler. Also, the soil sampler is powered by a 12v 3 rpm motor. Since my power system is 24v I have to either draw off of 1 12v battery (which isn’t recommended because it will cause an uneven drain on your primary batteries) or have some load balancer in place. The other obvious option would be to have a separate 12v battery that could be used for the bulb lights, neon and sound amplifier. I will option for a separate 12v 12ah battery. This should give me a full days capacity at shows and special events (I am only looking for 8 hrs of use). There was another consideration. I could change the motor of the soil sampler to a 24v geared Tsukasa electronics company motor. I seriously thought of that but then considered the issues with the lights in the torso and a further breakdown from 12v to various other voltages. I found a power distribution board that starts with a 12v source. It breaks down voltages for your RC receiver and other components like the 3.3v for the teeth lights, 6 volts for the belly, finger and brain lights and 5 volts for the RC receiver. Therefore I opted to stay with a separate 12v battery that I will keep in the CSS by one of the vents (so I can R&R quickly or just charge it easily).

CAD Drawings of my B9

The CAD drawings that so many of you have asked me about are rolling in now. This should allow you to have them made at your local machine shop or allow you to make them yourself. There are over 100 drawings and at $25.00 a page you can figure out how much it costs me to have them drawn up.
As soon as I have all of them I will send out an alert to the group. I think this is the first step in getting standardized drawings that fit with established club produced parts. As I have mentioned in previous club posts, these plans are for club use only. If you use them then you are agreeing that you are using them for yourself and will not take these plans to form anycommerical or financial venture without my expressed written permission. I own these designs. They are copyrighted. I am spending a lot of money having these professionally drawn for the benefit of club members. Please do not abuse this gift! I will accept donations for them but I will not demand a charge unless you require them to be physically sent out or mailed.  Let me know what you think about them and if you require something that I may not have.

The Bubble

Without a doubt the best production bubble I have seen has been Fred Barton’s. It is nice and clear but thin and easy to damage. In addition, Paul Felski’s bubble from “across the pond” is also very nice! It’s good to have quality vendors that allows you a choice for parts. I got to meet Paul last year at ROBOCON 2007 and had the opportunity to look at his bubble from his B9 pictures. I chose Fred’s since I am state side. Someday I hope to meet Fred as I hear he is an interesting character!
Anyhow, back to lessons learned….don’t bring the bubble out until you are ready to install it. If you leave it out, curious hands, house keepers and other family members will make their way to it where they find out just how light and fragile it is so take it from me …put it away in a safe, hidden place till you are ready to install it.
When you are ready to start drilling holes in the bubble make sure you “key” the bubble. Mark the front of the bubble with some blue painters tape. Make sure you tape/mark the front of the top and bottom part of the bubble.
Another thing I learned is that it helps to use a special drill bit when making the holes for the lower lid and brain cup holes. The drill bit needs to be made for plastic drilling (yes there is such a drill bit). Drill bit #40 and #50. You can get them at McMaster-Carr.com. When I received mine from Fred, I had to open up the center hole for the neck bracket (just a little bit). Take your time with this. Mike Joyce was kind enough to offer this procedure for fitting the bubble:
Carefully mark the location where you want the 4 holes on the bottom plate (I say four because the original had four.) Drill the 4 holes in the bottom plate slowly using a standard #50 drill bit.Tape the the bottom plate to the bubble using masking tape, etc. in the exact position you want it (centered). Be sure to mark both the bubble and the bottom plate “Front”. Put tape on each, etc. Match drill the 4 holes in the bubble using the bottom plate as a guide and again use the #50 bit. Remove the bottom plate and enlarge the 4 holes with a #40 drill bit. Use a counter sink bit on the bottom plate as required for #2 flat head screw to set flush. Attach the bubble using four #2 x 1/4″ screws. These are McMaster Carr part number 90006A077. The original used these small screws as well.
Stay tuned for our next episode: “Electronics of the B9. The inside story”

B9 Brain, Lights and Crown

The B9 Brain was from Scott Sanderson. The basic body was copper coated to hold paint better when I received it. I got some white transparency material and sprayer the frost mist from any crafts store to serve as a diffuser for the brain lights. I also sprayed the frost in the brain eyes to give it that same look from the show. Inside I have Tom’s brain light kit. His kit has clear LED’s. I took some magic markers and colored the LED’s for a special, different effect. The beauty of this is if I don’t like it I can wipe them off and I am back to the standard B9 white lights.
I also like the LEDs because they only require 6 volts and do not produce any noticeable heat. That is very important so over time my bubble wont glaze. In addition, something not every B9’er seems to know is that the top of the brain is mirrored. So I had my lid polished to a mirror finish. I thought about chroming it but I think I got a good enough reflection to get a good effect when the crown is moving and when the upper lights are blinking. You be the judge.
The crown was from Bill Kendzierski. It is a highly polished stainless steel work of art.