Author:electricloserI enjoy learning about electronics. I am self-taught. I finished my Electronics for Dummies, and moved on to Semiconductor, NJATC. Now, I am trying to learnC language for my Arduino!
Intro: Robotic Spider V8I needed a project that would use all my servos, so I decided to make the do-nothing, worthless spider. If you have fischertechnik and servos to waste, this is the projectfor you! Really, this flopping spider makes for a great learning project. The main goal of this project is to teach the fundamentals of servos, synchronizing them,programming them, and understand the range and strength of servos. The results are very amusing!
Fischertechnik? What's that?Legos have bricks, K'NEX has blue and yellow connector rods, but what does fischertechnik have? In truth, it has way too many pieces to give names to! Fischertechnikis definately not as popular as legos or K'NEX, but I like it much better. It's very good for exercising building and construction skills. Here is an excerpt from Wikipedia onfischertechnik"Fischertechnik is a brand of construction toy. It was invented by Artur Fischer and is produced by fischertechnik GmbH in Waldachtal, Germany. Fans often refer toFischertechnik as FT or ft. It is used in education for teaching about simple machines, as well as motorization and mechanisms. The company also offers computerinterface technology which can be used to teach the theory of automation and robotics."I will be calling fischertechnik FT as mentioned above.
Here's a video of it walking.
Step 1: Ingredients:Tools:
Hot glue gunRazor bladePhilips ScrewdriverDrill with 7/32 drill bitDremel with very tiny drill bit (a little bit smaller than the screws that come with the servo)
Electronics:
6 AA battery pack and alligator clip8x micro servos and attachments30+ jumper wires or pin headers.BreadboardArduino and power
Image Notes1. Fischertechnik2. Breadboard3. About 30 jumpers4. Hot glue gun5. Power for Arduino6. Tiny drill bit7. 6 AA battery pack for servos8. Dremel9. Phillips screwdriver10. Arduino11. Micro servo with attachments12. 1 alligator clip13. Razor blade (for removing hot glue)14. This is my BOSS drill!15. 7/32 bit (one size smaller than 1/4 on a standard drill set. 1/4 will work as well
Step 2: Building the FrameSince I don't know what to call the FT pieces, I'll just show the pictures to building the frame. Make sure to look at the captions.Assuming you have fischertechnik, you can just tell what pieces I'm using to build this. I'm sorry I can't offer much more of and explanation!
high. All the these will work. In my spidey, I used the middle piece.2. There needs to be four grooves in between the bricks. If you are using the same11 groove piece like I am, just put two on the ends, and one in the middle. Haveyour servos ready make sure they fit!
2. You are going to do this on the other side as well, reversed.
Step 3: Mounting the ServosNow get out your dremel! The servos conveniently fit between the 'bricks'. Drill a small pilot hole, then using the screws the servo came with, screw them in. If you don'twant to screw into you pieces, that OK, just use some hot glue, but, it's always easier disassemble if you use screws. Note: You will want to screw these on BEFORE youput on the arms, or else the arm will be in the way of your screw making it difficult. And why do I know this? I'll let you guess =) Repeat this on the other side.
Image Notes1. Mount the other servo on the other side reversed. Repeat this on the front side.2. Notice the connection point is facing the toward the closest edge---------->3. Forget this servo- it shouldn't be there :)4. My smallest dremel bit.
Image Notes1. Perfect fit!
Step 4: Mounting the Servos on ServosYou will first need to screw on the circular servo attachment. If the servo is facing away from you, turn it all the way to the right. See pictures.
Now the circular servo arm is different from the other arms; the screw sticks up above the plastic unlike the other ones, which the screw head sinks below the plastic. So,with this bump in the middle, a flat surface cannot be mounted totally flat, instead it will wobble and pivot around the center. To fix this, I'm taking a 7/32 bit (one sizesmaller than 1/4 on a standard drill set) and drilling a small indent on the servo that will be glued on top of the base servo. See pictures. Then using hot glue, glue the twoservos together.
Step 5: Mounting the Spidey Legs!This part is little tricky. I'm going to put a little video up to kinda help you understand how to mount the arms. See the pictures how to make the arms. You will need four ofthese. See the video in step 4 for glueing these on.
Image Notes1. These arms are 452. Make sure this part is turned the opposite way as the other.
Image Notes1. One of the 45 arms connect across these 4 holes.2. One of the 45 arms connect across these 4 holes.
Image Notes1. Connect it all together, and you have 3 more to go!
Step 6: Seeing it all TogetherAfter you mounted all the arms you will want to check them for full range of motion.
Image Notes1. Notice the generous portion of glue to hold the arm on.
Step 7: Creating a Diagram For ReferenceNow, this is the most helpful step of all. Create a diagram like the one shown in the picture, and figure out for each servo which way is 180 deg. and which is 0 deg.. Thennumber all the servos. These numbers are what you will be using in your Arduino program.
Image Notes1. Forget this. It's for something else I have written on the other side of my page.2. This is the top left pan servo3. This is the bottom right up and down servo. In order to make it go all the way to the bottom, I must type in 1 deg. in my code.4. All these 10's should be 0
Step 8: BreadboardingPull out all 30 of your jumpers! Wire up everything according to the schematic. Here's how it works. Each servo has 3 output wires, power, ground, and control. Connectthe Vcc and GND from servo to the Vcc and GND rails of your breadboard. Connect the 7.5 volts from your battery pack to the GND and Vcc rails of your breadboard.(Since most battery packs are for 6 AA, take out one of the batteries and use a jumper to bypass it. This will then give you 7.5 v instead of 9v.) Then, following yourdiagram you made earlier, connect the servo control wires (yellow or orange, I've even seen white) onto pins 2-9. For instance, servo 1 is connected to pin 2 on Arduino.Servo 2 is connect to pin 3 and so on.
Image Notes1. Here is the quick breadboard view.2. Actually 5-12v3. Sorry, this should be 7.5v
Image Notes1. The full breadboard view.2. Make note: Both grounds MUST BE CONNECTED together. If not, it willexplode. . . no, not really, it just won't work.3. This should be 5 AA batteries
Step 9: Aligning the ServosNow, here is the time to work out the code. The first thing to do is to make a new Arduino project called, Aligning Servos. In this project, you will align all the servos. So,what you need to do is to find out what degrees (1-179) you need to type in to make the up and down servos (the servos on the top with the arms connected) level withthe ground. Then, get the left and right servos (the servos on the bottom) level as well, having the stick straight out. Lets examine the code.Then, look at the second picture in this post to see what this code does for my spider.
{ // all the motors level fowards and backwards servo1.write(15); servo2.write(100); servo3.write(179); servo4.write(95); servo5.write(160); servo6.write(140); servo7.write(15); servo8.write(85);
}
Image Notes1. Type this to include the servo library.2. This is telling Arduino that servo1, servo2. . . are servos.3. This is attaching the servos to they're pins. (servo1 is going to plug into pin 2and so on)4. These were all the numbers that I used to get all the servos equal. Oddnumbers are the up and down servos and the even are the spin.
Image Notes1. The code above (and below) aligns the arms. They are fairly straight, butcould still need a little bit more tweaking.
Step 10: Up and DownYou will now need to find out the values for making the legs actually lift the spider off the ground. Make a new project called Up and Down. This project make the legs ofthe spider move up and down. Notice the opposites will lift up first. See video.
And here is the code I used. Yours may be similar.
{ servo2.write(100); // these numbers are to keep the spin servos put. servo4.write(95); servo6.write(140); servo8.write(85);
servo1.write(50); // M1 Up servo7.write(50); // M1 Up delay(500); servo1.write(25); // M1 Down servo7.write(35); // M7 Down
delay(1000);
servo3.write(135); // M3 Up servo5.write(120); // M5 Up delay(500); servo3.write(150); // M3 Down servo5.write(140); // M5 Down
delay(1000);
}
Image Notes1. Refer to previous picture for what all this does.2. VERY important. Take the values for the pan servos and place them here. This will keep them steady and straight out while the other servos work.3. Opposites go up, then down... loop forever.
Step 11: Forwards and BackwardsNow we will need to get the pan servos to pull forward, and push back.Here is the code I used. Yours may be similar. When your done it should look like this. . .
Image Notes1. See earlier pictures if you forgot what this was.
Step 13: ConclusionUnfortunately, I wanted to call this the robot spider, but I couldn't really, because it doesn't react in any way with it's environment. I guess you could add some sensors orsomething like that, but this project really isn't mean't for that. I hope you enjoyed my instructable and If you have any questions or comments please post in the commentbox below and I will attempt to answer them as best as I can!
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