Check out this simple little robot which does nothing else than sweeping the ground beneath: http://www.evilmadscientist.com/article.php/bristlebot
Why not make a larger version and make it clean your crypt?
So I decided to make something with RC-servos using the Arduino board and the sensor shield which I recently purchased.
I went ahead figuring out how to send arrow signals from my computer to Arduino using USB interface.
Using void setup() { Serial.begin(9600); } on Arduino and screen /dev/ttyUSB0 9600 on my computer, I managed to send commands back and forth. I hooked up the standard servo library and write some code before I mounted the Arduino board on my mini rock crawler. I now had a computer controlled car. Because of Arduino`s simple interface I had it all up and running around an hour. Check the small video and code below.
You can view and or use the code as you like below. (Sorry about the indention, Wordpress messes it up).
//
// OBJ
//
Servo servo1;
Servo servo2;
// VARS
int readByte;
int servo1Angle = 90; //default servo angle
int servo2Angle = 90;
int minPulse = 700; // minimum servo position
int maxPulse = 2300; // maximum servo position
void setup()
{
servo1.attach(2, minPulse, maxPulse); //connect servo
servo2.attach(3, minPulse, maxPulse);
Serial.begin(9600); // start serial
Serial.println(“Ready\n”);
}
void loop()
{
if (Serial.available() > 1) // procced when two bytes is avaiable
{
readByte; = Serial.read(); //read first byte
if (readByte; == 91)
{
readByte; = Serial.read(); //read second byte to determine arrow type
if (readByte; == 65 && servo1Angle <= 180) //UP
{
servo1Angle += 5;
}
else if(readByte; == 66 && servo1Angle >= 0) //DOWN
{
servo1Angle -= 5;
}
else if(readByte; == 67 && servo2Angle <= 180) //RIGHT
{
servo2Angle += 5;
}
else if(readByte; == 68 && servo2Angle >= 0) //LEFT
{
servo2Angle -= 5;
}
}
}
// set servo positions
servo1.write(servo1Angle);
servo2.write(servo2Angle);
delay(15);
}
After running this motor to hard outside, I managed to burn the motor. You can see pictures of the “burnt” motor in the gallery below.
First of all I opened the motor to take a look noticing protective isolation layer on the copper were melted. Not so strange, because when I approaced the motor after the plane fell from the sky, it was insane hot.
Before removing all wire I measured the wire diameter to 0,30mm. I found this king of wire inside very small tranformators in a computer power supply.
By using this picutre, found on this page. I was able to re wound the motor.
I actually did wound all the poles at the same time, well, one by one, but all three wires were in use, if you follow.
After finish wounding I had to connect wires together to make only three wires, brush less motor has three out wires.
Since it`s a pretty fast motor I made a delta hookup, but I did a mistake at first. This motor should have around 195mOhm per 14-turn, maybe I did not mention it is a 14-turn motor. Which means each pole (there are nine here) needs 14 turns of isolated copper wire and in a small motor like this one, it`s not that easy. Anyway, by hooking up wrong end`s I broke a ESC of mine ($10) so I had to buy another one.
The motor works just great now and I might add a video later.
Gallery
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| Fixing brushless motor |
An interesting link were floating around on IRC today, containing a video showing devices being powered wireless. Take a look.
We`re about to choose a new project at school, maybe this is a step up from our mechanical hand?
This article will have an overview of our school project (term 2/6). There are three heads on my group. Our goal with this project is to make a mechanical hand which can move it fingers like a real human hand, electronically controlled. Even point at, pick and crush things!
Before we decided what project we wanted to do, we had several ideas. A sensor based 4wd vehicle to mention one of them. After setting our goal on making a mechanical hand we did our research on google search/images. We only found a single hand (image below) which seemed something we could do in our time, among many other professional vendors.
It is required by us to setup a budget and plans for the rest of the project. All groups in my class needs to be finish by week 21 when the presentation is.
Me and my group are finish developing the hand and making it. We also got our plans for each week ready. Luckily, we reached our milestone for this week, were we wanted to figure out signal’s need for the RC-servos.
The hand is going to be drifted with five Futaba 148S servos, they cost about $19 each and provide 4.1KG of torque with 6.0v and a twist time of 0.19sec/60 degrees. So far, our budget is on $94, but it may increase by a few bucks due to some small components we might need.
We are still working on the sinew/rod’s before installing servos. We might just clean it for all welding points as well.
Update #1
We have now figured out the servo signals and created a physical servo controller. We are using the 555 timer, two actually, because we had an issue with only using one. It didn’t create a stable output before 30 seconds after start. The
surrounding components, capacitors and resistors are our variables, changing the signal length.
We also did make a counter using two J/K FlipFlops and a dmux to convert the signals.
The circuit’s for this hand is so complex, that we decided to program it all into a Altera card. Logic scheme will be available later when we have completed the project.
Image album.
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| School project – Mechanical hand |
Video of hand in action.
Finger control.
Bottle holder.
Today our lesson had come to diodes. Our task was to make a DC from AC using capacitor, resistors and diodes. Everything went pretty well and we (my group) or any other of the groups blowed-up any of the electrolytic capacitors we used.
We measured some of the values and checked them against our data’s too see how far teory was from truth. If I remember it I will put our final rapport out here to.
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| Laboratory – diode and zenerdiode |
I received my Tamiya TA-05 car one week ago. Due to allot of work I haven’t gotten the time writing about it. It’s a pretty neat car and I’m pretty much done with the whole car. You can see some pictures of the build process below.
Electronics in use at the moment:
- 540-motor (stock)
- JR servo
- Kyosho 27-mHz (crap)
- 13 turns ESC
- 11.1v LiPo battery
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| Tamiya TA05-IFS |
After an ugly crash with my T-rex 450 I managed to strip an Hitec 65MG (as in metal gear) for the first time. It was a new milestone for me. I was going to order a new set of gears from Elefun, but they were out of stock. I contacted them and was told the distributor was out of stock. It could take weeks before I could have the bird back in the air. Something I didn’t want to risk before the next indoor RC meeting.
It all boils down to my order over the seas which just arrived. Let’s take a look, shall we?
The box should contain:
I had some minor problems with my new T-rex 450 SE v2, the belt kept jumping off. I solved it by removing the idle-pulley, but now have I bought a replacement for it which looks to do the job.
Three servos for my old t-rex 450, one tail servo and two for cyclic. Also added servo grease for the servo I will be changing gear on.
The transmitter (later refereed as TX) battery, 2200mAh 11.1v Kong Power battery. I’ve read about someone running theirs for 5 weeks without charging. I guess mine won’t last that long since I use my TX on the simulator as well.
Almost forgot to add the charger and lipo. This is the best charger I have ever used. I might do a review of it some day.
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| Readyheli package |
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