The third and most likely last Dragon, Epsilon covers and fixes many of the problems that were present in the Bipedal Dragon Prototype (B.D.P.)
First looking at the gearing on the underside of Epsilon, (Picture 1), it is much shorter and less complex than that of B.D.P. The new gearing has less friction and delivers a gear ratio of 1:105 (please tell me if the output goes before or after) whereas the old gearing only delivered a gear ratio of 1:45. (this was taken from the last gearing before stripping B.D.P. of its innards)
Also to be noted is the change of two pieces. These pieces are what drive the legs and connect it to the driving axles. Picture 2 is a comparison chart between the old and new pieces.
The neck, too, has undergone some changes. It is about 4 cm longer, and the track which the activating mechanism is on has been rebuilt for smoother operation. You may also note that the head is larger. Looking back on B.D.P., its head was sort of small compared to its body.
The feet also now have two rubber gripper assemblies, similar to what was found in the left foot (possibly the right? Its only in one in the instructions...) of Alpha Rex. These help Epsilon's feet not slip backwards while walking.
Not pictured are:
♦Beams that strengthen Epsilon's body. They connect to the legs to give the most resistance to bending under weight as possible.
♦New tail. It looks the same, but it cannot separate in the joint or where it connects to the body as easily.
♦New connectors for weightshifting. THe legs pull the NXT side to side, and a special axle is used on each side to help keep them connected and not dangling uselessly.
♦New wing connections. The connections allow the wing to be pulled off without the axle being pulled out with it.
If you remember, the shield for the NXT was a feature first built onto the original Dragon Prototype. In B.D.P., the shield could be lifted up for screen access of the NXT. However, the shield could not be lifted up very high due to the construction towards the top.
This has been fixed here. You are able to pull an axle with a small handle on it out, and the shield can swing towards the left. The shield is then pulled towards the user, and due to a 3-unit grey pin, extends one unit and can be rotated out of the way. Don't worry, its actually very simple to do.
The NXT still has a sound sensor and light sensor directly linked to it, but I added some pieces to protect the sound sensor from motor noise. I am not quite sure how well it can work, but the theory is acceptable. See Picture 3 for the piece. I do not know what it can be classified as... it looks sort of like a Bionicle piece, though...
Although not directly pertaining to the NXT, another improvement is the innards of Epsilon. The Ultrasonic Sensor and Motor A have wires that run through the gearing area, and the gearing area was also open in the B.D.P. This is fixed with a cover. The wires are redirected with the help of some retaining axles, and the gears are protected from whatever lays around the desks and floors of the house.
On a side note:
WARNING: to all NXT builders. Do not put wires near gears. If the wires and gears rub up against each other, the gears can start to eat away at your wires. A good sign of this is if you have black powder on your gears and other pieces of your project.
Yes, measurements. They will be in both English and Metric units. Here they are:
♠Length from head to tail (neck extended): 2 feet, or 0.6096 meters
♠Length of extended neck: 7 inches, or 17.78 centimeters
♠Height (average): 1 foot, or 0.3048 meters
♠Wingspan (or the width): 13 inches, or 33.02 meters
♠Weight: 4 pounds, or 1.81436 kilograms
♠Program: 26.6 kb or 29.6 kb, depending on a MyBlock.
Yes, these are all accurate measurements. Even the weight.
I have also included a picture of Epsilon at its maximum length for an idea as to how long it is.
Epsilon technically has one program, but I think of it as two. This is because you can select three "options" using a menu.
They are:
♣Epsilon Program
♣Demo Program
♣Termination Option
•"Epsilon Program" is the main program, in which Epsilon senses its surroundings and acts accordingly to it. This is similar to B.D.P.'s program. Of course, a few things have been changed. The program uses variables instead of File Access blocks, and some of the behavior choices have choices within them. In total, there are now 6 behavior possibilities.
•"Demo Program" is a simple demonstrational program to show what Epsilon's abilities are. The demonstration shows Epsilon walking forward, detecting obstacles, and using its Roar function.
•"Termination Option" allows you to quit the menu and exit the program.
There is also an in-program "Emergency Termination". This has two ways of ending the program.
•The first is the obvious manual termination, handy for situations such as Epsilon about to fall off a table, or running into nonmoving obstacles.
•The second is the not-so-obvious automatic termination. This happens when Epsilon senses its batteries do not have enough power. Epsilon will end its program if the battery level reaches below 6300 mVolts. This happens if the batteries simply don't have enough power, or if the motors are struggling, since they often try to get more power from the batteries.
The program was made with NXT-G version 1.1, so no MiniBlocks were needed in it.
If you intend to use this program, please download all MyBlocks on the page, as well as the Battery Level Block from NXTasy. (No, I'm not advertising). It's also advised you get the Blips sound addition, and perhaps a roaring sound for a dragon.
Oh, and another warning: If you have "custom sounds" in your NXT-G, save the sounds in a separate folder before upgrading to Version 1.1. Then replace them back into your new version of NXT-G.
Slot 1: Screenshot
Slot 2: EpsilonDriver
Slot 3: Roar MyBlock
Slot 4: Bite MyBlock
Slot 5: Terminate MyBlock
Please see my project list and find "Epsilon MyBlocks Continued" for the rest of the MyBlocks. I apologize for having so many... but it really makes loading it in NXT-G so much quicker.