NXTasy.org Challenge No. 3 -
“The ANxT”
MISSION: Built a NXT ‘Ant’
Ants are remarkable little creatures, capable of lifting weights several times their own body weight (if you search the net, you frequently find sites quoting that ants can lift 10, 20 and even 50 times their own body weight. However, I could not found a scientific proof for these values…).
In NXTasy challenge #3 you need to build an ‘Ant’ using ONLY LEGO parts and the NXT, or for short an ‘ANxT’. You are NOT limited to one NXT or one set in building your ANxT. The goal of your ANxT would be to move an object (the ‘weight’) a distance of 1 meter without touching the floor. The grade will be 50% determined by the object weight/ANxT weight ratio, 30% by the mass transfer rate (see below for a clear explanation of this term) and 20% by how much your ANxT is, well, ‘antish’…
Oh, and the object must be bigger then your ANxT in all dimensions, did I mention that already 
?
RULES:
1. The ANxT should be constructed only from official LEGO parts. This include LEGO Technic, regular LEGO pieces and any parts in the NXT set.
2. You should not uses third party sensors or any other product not manufactured by the LEGO company. Well… it won’t help you much in this challenge anyhow.
3. You should draw two parallel 1 centimeter wide black lines (preferably stick a black tape) distances exactly 1 meter apart (tape center to tape center). The two lines define three ‘regions’ A, B (the middle) and C. At the beginning the ANxT should be on region A and the weight on region C. At the end everything should be reversed - weight in region A and ANxT in region C. Being in some region means that looking from above, no part of the ANxT or the weight crosses the black line!
4. The weight can be ANYRTHING you like, as long as it’s outer dimensions (i.e. width, length and height) are ALL LARGER then the LARGEST outer dimension of you ANxT.
5. The weight MUST NEVER touch the ground in region B! You would not like to bring home dirty food, right? The minimal distance to the ground must be more then 1 centimeter while the weight is between the two lines.
6. Floor must be hard and featureless except for the two black lines.
7. To measure transfer rate, the NXT should start a timer and make a loud sound (audible in the movie) when the weight is first touched, and stop the timer (again making a loud sound) when it releases (or otherwise leave) the object on the other side. It should then show the timer value (in seconds) on the LCD.
8. You should find a calibrated weight to measure ANxT and object weight. I trust everyone that they play fair here, but if I suspect otherwise I keep the privilege of banning competitors from the challenge (and future ones as well!). I will convert the weight into grams, so don’t worry if your countrymen still use funny measures like pounds or oz.
You MUST read this ‘Questions and Answers’ topic dedicated to challenge #3 frequently. Any post by myself over this topic is as ‘official’ as the rules above! However, any post by other member should be considered a recommendation at best, until I reply to the
question at hand.
SUBMISSION REQUIREMENTS:
1. A photo showing measurement tape placed between the lines, indicating the distance is indeed 1 meter.
2. 3 photos showing measurements of the ANxT dimensions.
3. 3 photos showing measurements of the object dimensions.
4. A photo showing the timer value
5. A video showing the whole process - starting with ANxT in A and weight in C and ending with ANxT in C and weight in A. I prefer that you upload your file to YouTube (or similar sites) and send me a link. If you do, try avoiding descriptive keywords so your video will not be viewed much before the deadline. You can later modify your video and add keywords like ‘NXT’ etc. to make others find it more easiliy. If you choose to send me the video, please compress it into MPEG4 or any other common compression codec.
6. A photo showing the weight of the ANxT.
7. A photo showing the weight of the object.
8. A text file describing your work, the nickname you want me to use (if you prefer not exposing your real name) and your shipping address.
As allways, send all these by email to me: guy (at) nxtasy.org
GRADING:
The final grade of each ANxT will be composed of three - 50% from object/ANxT weight ratio, 30% from mass transfer rate and 20% ‘antish’ design. Each are described in detail below.
Object/ANxT weight ratio: for each competing ANxT I calculate the ratio of object weight and ANxT weight. The best ANxT (i.e. largest object/ANxT weight ratio) will get 50 points. All other ANxT will get a proportional number of points. So, for example, if the best ANxT reach object/weight ratio of 2 and your ANxT reaches 1 you get 25 points. Of course, the object/weight ratio mustn’t be integer - it can be 0.43 as well! Grades, however, will be rounded to the nearest integer value, so if your ANxT has a 0.43 object/ANxT weight ratio you get 11 points (and not 0.43*60/2=10.75 points). I round half integer values up, so for example a value of 18.5 will be considered as 19 points.
Mass transfer rate: when you bring home the groceries from your home garage, you probably notices that taking two begs slows you down more then one beg at a time, right? Hence the absolute speed must be somehow normalized by the weight of cargo. This is done by calculating the ‘mass transfer rate’ equals to the actual speed (in centimeters per seconds) multiplied by the weight (in grams). Again, the ANxT with the largest mass transfer rate gets 30 points, and all others get a proportional number of points.
‘Antish’ design: this time I decided to give some grade to the aesthetic part of your ANxT. The grade here is between 0 and 20 points. It is calculated as follows:
- Does the ANxT looks ‘antish’, i.e. has a ‘head’, a ‘body’ and ‘legs’? (If YES - 3 points)
- Does it ’sense’ her target (using ultrasound, not smell..) ? (2 points)
- Does it use some sort of clamps to hold the object? (5 points)
- Does it know to find her way home (i.e. uses sensor to detect black lines)? (3 points)
- Does the ANxT use legs for locomotion? (7 points)
SCORE BOARD:
A score board (showing only object/ANxT weight ratio and mass transfer rate) will appear in the beginning of the Q&A topic. I promise to update is as fast as I can (which isn’t fast at all, considering my available time..).
PRIZES:
Challenge No. 3 is sponsored by mindsensors.com. Best ANxT builder will be awarded a 60$ cupon for purchase in mindsensors.com online shop!
DEADLINE:
No ANxT will be accepted after September 15th 2007 October 1st. However, I STRONGLY urge you to submit ahead of time. It will be benefical to motivate others and you can check your position in the score board, resubmitting improvements if you wish.
Have an Enjoyable Summer Vacation (building ANxTs, of course) !
Guy Ziv
NXTasy.org
