Building the Tread Section
|
 |
My tread section is made of poplar plywood. I chose poplar over pine because
it is a much harder wood and is less likely to warp. I purchased the plans for the
Tread Section from Bermuda Triangle
Engineering. |
 |
I plan on covering the surface of the wood with styrene plastic.
|
 |
I cut out the soil sampler door opening and cut a 1/4 in.
thick styrene plastic door. I drilled a hole in both sides of the door near the top.
I inserted a 4d finishing nail into each hole. These will act as the hinge.
I then cut off the heads of the nails.
|
 |
I used my Dremel tool
to cut the slots for the hinge. |
 |
Here's the door
set in place. Since I will be covering the wood with styrene, it will trap the nails
in place. |
 |
4/10/01-
I added a rotary solenoid to the inside of the door. It now opens and
closes electronically. This will be controlled by a micro controller. |
 |
4/10/01
- Here's a picture of the solenoid on the inside of the door. When
powered, it rotates about 30 deg. I cut a rod to the right length
and connected it to the inside of the door with a pivoting hinge. Now I
need to work on the actual Soil Sampler mechanism. |
 |
5/12/01
- Well, I canned the rotary solenoid and went with a spring loaded door. I
scrounged up a lead screw and mounted the soil sampler to it. I am using a
stepper motor that is controlled by a Basic Stamp processor board. Using a
stepper motor allows me to change direction of the motor without using a motor
controller board. It also monitors the two limit switches and controls the
timing of everything. UPDATED -
SEE BELOW |
 |
Click
on the picture to the left to see a quick video showing the soil sampler in
action. |
 |
7/9/01
- I glued a piece of styrene to the front of the right tread section. I
used the Wood Goop and it seemed to soften the styrene so I had many areas to
fill with Bondo to get the surface smooth. It came out pretty good after
all the filling and sanding. Now just three more sides to go. |
 |
9/5/02
- I've ignored the tread section for over a year as I worked on the torso and
the internal electronics. I decided that I had better get it painted
before the cold weather sets in. Last weekend I textured it.
It came out pretty good. A few spots needed some extra texturing to
cover a few imperfections. It is suppose to be 90 this weekend (unheard of in
upstate NY in September), so I hope to do some painting. |
 |
10/15/02 - The tread section is finally painted. I
installed several of the wheels and moved everything down to the shop in
my basement. It seems that we had 80 deg. weather at the beginning
of October and 40 deg. weather at the end. Nothing more will be
accomplished in the garage until next year. I now need to re-install
the soil sampler mechanism. |
 |
6/11/03 - Here's a shot of the underside. Not all
of the wheels are installed here. I need to thank my brother Pat, who
had some of my wheels turned down to the proper size. He's the
Mechanical Engineer in the family and had the know-how/connections to get
them done properly. So, if you're ever in the
market for an air tool, you can't beat Ingersoll-Rand
air tools. (Shameless Plug).
 |
 |
7/27/03 - This is the power
inlet (IEC-320 type) on the back of the right tread section. It also
has a master on/off switch built in. |
 |
7/27/03 - I've started wiring the primary (120 V ac) circuit
inside the tread section. I've used two terminal blocks. The
one on the left will have the Line and Neutral wires. The small one
on the right will have the safety ground. The small black box is a
surge suppressor. I don't want any lightning strikes damaging my
Environmental Control Robot. |
 |
8/5/03 - I mounted the two
power supplies in the left tread section. This is a picture from the
top looking down. The closest power supply is the 5 V dc supply and
the bottom, open frame power supply is the 12 V dc supply. It is not
fully wired in this picture. |
 |
8/5/03 - Here's a side shot
of the 12 V dc power supply. I wanted to build in some trouble
shooting features so I added this test panel. It has test points for
both the 5 V & 12 V as well as status lights to tell me if the voltage
is present. I have also added the wire harness in this
picture. |
 |
12/19/03 - I've decided that the Stepper Motor that powers the Soil
Sampler drive screw is not fast or strong enough. I've replaced it
with a larger, dc motor. This means I had to reprogram the controller
since this motor works differently than the stepper motor. Also, I
added an H-bridge so I can control the direction of the motor. I'm
using the same H-bridge made by National Semiconductor (LMD
18200) that I used for controlling my torso rotation. I build a
single motor controller on a bare perf-board. There are very few
support components in the circuit and it gives me complete control of both
the direction of the motor and the speed. This is a great motor
driver. |
 |
This picture is a little cluttered but you can see the
Basic Stamp board at the top and the H-bridge board in the center.
To the right of the Stamp board is the transistor board that drives the
rotating head of the soil sampler.
I also added a "homing" feature to the control software.
On power up, if the Soil Sampler is not in the up position, it will start
moving up until it is. I found this a nice feature because during the
development of the circuit & software, sometimes I would power it down
before it had completed it's "soil sampling" cycle. Also, this means I
know it is in the home position before I start each soil sampling cycle
|
 |
12/21/03 - I interfaced the
Soil Sampler circuitry to my Infrared received circuit board. I can
now start the soil sampling process with the touch of a button. Also,
I added a 5 second "power up" wait period before it starts looking for the
signal from the IR circuit board. I found that the Soil Sampler
circuit would sometimes activate when powering up the entire robot. It
appears that all of the circuit do not come on line at the same time (which
makes sense) so some
initial logic signals are misread. At least that's the story I'm
sticking with. The 5 second delay solved my problem. The
remote is an off-the-shelf Radio Shack universal remote. I programmed
it to send the standard SONY signals, which is what my IR Interface circuit
board understands.
Update - I've nix'd the IR
remote for a RF remote that worked out much better. See my
Remote Control page |
 |
I've
installed my first upgrade, real rubber treads. I purchased them from
David Huber through the B9
Robot Builders Club. It took me about an hour to measure, cut and
install. |
 |
They look great and appear very durable.
At this same time I found the loose wire going to the soil sampler motor
that prevented it from operating at Wonderfest 2005. I hadn't really
looked until now, but I'm glad it was something simple and obvious. |
