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1021  Using Arduino / Motors, Mechanics, and Power / Re: TowerPro 9g servo + P2N2222AG transistor on: January 23, 2012, 04:56:06 pm
You probably won't get rid of servo glitches on startup. What you are most likely seeing is that the H-Bridge that drives the motor, along with other circuitry inside the servo is not turning on cleanly and this is what causes the servo to jump. In many applications this is not a problem because, if the transmitter is on the servos quickly respond to the current control positions. You are going to get some twitch, it just depends how quickly teh control signal is there to move them where you want them.

You might also look into a small relay. Would handle power to all you servos with one device.
1022  Using Arduino / Motors, Mechanics, and Power / Re: PWM with TIP120 driver makes motor beep on: January 23, 2012, 04:04:06 pm
Yep -

You might need to hook up a capacitor to the lead going to the base of the transistor (arduino pin 5 to ground). What you are hearing is the PWM signal in the motor. PWM Is not quite analog, but does have some of the properties (most of the time...)

You might have a problem - the motor might be designed to run in a certain speed range and won't perform well outside this range. If you want slow rotation you would be better off with a gear motor or a stepper motor.

Try starting the motor at PWM of 255 and slowly reducing that number. You need enough torque to get the motor started and then it will require less torque once it is moving.

What is this motor conected to?
1023  Using Arduino / Motors, Mechanics, and Power / Re: 5v 28YBJ-48 Unipolar Stepper Driving Me Mad! on: January 23, 2012, 03:56:43 pm

Angrily (tired at this point), I picked up my mini vice and with a well aimed (all be it accidental) shot, managed to put a rather large dent in my guitar!! LOL.

Sounds like someone needs to grow up or get some anger management classes... Sure wasn't worth the mark in the guitar and didn't help the vise any...

How far was it turning? Was it repeatable. Those 2 will give you quite a bit of the answer of whether it is working. Next is - How fast are you stepping? If you are stepping too fast you WILL miss steps. Could just about drive this one directly from the Arduino - just add diodes across the windings. (Diodes won't conduct when the Arduino is at 5 V.)
1024  Using Arduino / Microcontrollers / Re: Burning bootloader on: January 23, 2012, 02:13:59 pm

i dont use an external programmer, i want to use my uno to burn the bootloader onto the atmega168 in the "2nd" arduino.

where should i connect through the icsp header?!

The problem is that you don't have the icsp header. You need to look up using the Arduino as an isp, and the information exists on many site on the web. Try the search term - arduino as isp - and read several of them. they will show you what pins need to be connected and what commands to use. It requires 6 wires -  from Arduino pin 10 to 168 pin 1 (reset), from Arduino pin 11 to 168 pin 17, from Arduino pin 12 to 168 pin 18,  from Arduino pin 13 to 168 pin 19, from Arduino +5V to 168 pins 7 & 20, and Arduino GND to 168 pins 8 & 22 and on teh Arduino board a 120Ohm resistor between +5V and Reset.
1025  Using Arduino / Microcontrollers / Re: Doesn't autoreset after loading new sketch on: January 23, 2012, 02:01:45 pm
Are any of your voltage levels marginal in this application? It is possible that you have a chip that might be more sensitive to voltage levels and this is causing some sort of hangup.
1026  Using Arduino / Microcontrollers / Re: Chinese clones on: January 23, 2012, 01:52:38 pm
Why buy the Chinese clones? With a minor bit of effort you can program the bare chips and use them. I have made my own programmer board with a 20 pin and 28 pin socket and a 16Mhz resonator and I can program 8, 20 and 28 pin chips on it using my Arduino Uno. ATmel and whichever supplier I use make a buck and I don't have to wonder about the pirate company from China or Brazil.

Programing a chip directly is so simple, and takes no extra time and then you can embed the chip any way you want to. Might be better off investing a little of your time into designing a board and having a small batch made instead of buying a ripoff clone.

Personally, I am glad I got the Arduino Uno board to start with. I was able to get a device that worked, I was able to support the Arduino Project and I got the software and this forum. Great deal and a great price.
1027  Using Arduino / Programming Questions / Re: Hardware interrupt problem on: January 23, 2012, 01:08:13 pm
So - you just want this code to execute when the interrupt occurs?

You have 2 choices -
either put the code in the interrupt routine and it will execute whenever the interrupt is received


In the interrupt routine set a flag that you reset inside your routine in loop.

Kind of like this -

void Loop(){

    if (Flag) {
         your code here...
         Flag = 0;

void Interrupt (){
   Flag = -1;

Working from my old and tired memory - you might want to swap the Flag = 0 and Flag = -1 to have it work properly.

Warning - will the code you want to run every interrupt execute in less time than the time between interrupts?
1028  Using Arduino / Motors, Mechanics, and Power / Re: Arduino chip as Stepper Controller on: January 23, 2012, 12:48:58 pm
Worked on the board for my first driver. Got it mostly soldered up and got to thinking that I would have to change the bleeder resistor as 56Ohms wold draw too much current from the 328, so I will have to pull them and get some resistors in the 120 to 220 range. Oh well, minor setback.
1029  Using Arduino / Programming Questions / Re: Cannot use the ArduinoISP to program attiny85. on: January 20, 2012, 08:51:40 pm
There is a problem with the 1.0 version of the IDE, load ArduinoISP using the 0.22 version of the IDE and it should work just fine.

Someone else had documented this problem so when the ArduinoISP didn't work when loaded from 1.0 I brought up 22 and loaded it from there and it worked just fine.
1030  Using Arduino / Motors, Mechanics, and Power / Re: Arduino chip as Stepper Controller on: January 20, 2012, 08:47:31 pm
Well it works. (almost didn't, hooked the chip up upside down and generated a little heat...) plugged the chip in and hooked up to my led drivers and it works.

Got a few things to take care of before I can play with it too much so ... The first of the week i should have a stepper driver working.

So - It is really rather easy to hook up an ATTiny2313 to an Arduino programmed as an ISP and load the code into the 2313. I did have to use version 0.22 of the Arduino Environment to have teh ArduinoISP work properly, but I stumbled across that little piece of info somewhere along the way.
1031  Development / Suggestions for the Arduino Project / Adding other boards to the Arduino IDE on: January 20, 2012, 01:31:45 pm
was able to get hold of the Arduino-Tiny files and add those processors to my Arduino 1.0 files.

What i am wonderring about is how to add another processor/board to the IDE. I would like to play with a ATMega324 (all those I/O pins...) but would like some document that would outline the process.

While I could do all the work using WinAVR or AVR Studio 4 (5 is too slow...) I like using the Arduino IDE and it provides the level of programming that I need.

1032  Using Arduino / Motors, Mechanics, and Power / Re: Arduino chip as Stepper Controller on: January 19, 2012, 12:24:18 pm
Got my chips and parts on Monday and Tuesday night I put together a board for programming ATMega328 and ATTiny2313 chips. I didn't order any 120Ohm resistors so I had to wait til yesterday to test it out.

Used AVRDude to program the chips and had to add a section to the avrdude.conf file for the ATMega328 as it only had the ATMEga328P. I could have added the -F argument to the command string, but it was just as easy to add a section for the 328. Copied the whole 328P section and made 3 changes - in the 2 locations where 328P appeared I erased the P and I changed the System Descriptor bytes (avrdude reports what it finds if it doesn't agree) from 1E 95 0F to 1E 95 14 and everything worked. Took the chip out of the programming socket and swapped it for the chip in my Arduino board and loaded it with Blink.

I also put one of my ATTiny2313 chips in the and used the Arduino IDE to load the code to the 2313 and it seems to have loaded just fine. Have to hook up a circuit and test out the chip. Will probably be Sunday night before I get the chance as I have too much in my schedule between now and then.

I will post a picture of my programmer board and a schematic the first of the week.
1033  Using Arduino / Motors, Mechanics, and Power / Re: Second-hand stepper motors on: January 19, 2012, 12:11:19 pm
The biggest problem with found steppers is that they tend to be Bipolar steppers. That means there are only 4 wires and you need an H-Bridge to drive them. Unipolar steppers have 5, 6 or 8 wires and are simpler to interface - you only need 4 transistors and 4 diodes(or 4 irf520 or similar FETs) and your Arduino.
1034  Using Arduino / Project Guidance / Re: Stepper driver interference/noise ? on: January 18, 2012, 01:47:07 pm
From your description this is what I think I am reading -

you have 2 stepper drivers connected to you Arduino.
The Arduino is supplying the 5V DC for the logic side of your stepper drivers.
The output side of the drivers shares a 12VDC supply.

When running both devices at different rates you get some noise to one or the other driver.

I would question whether the Arduino has enough power to cleanly supply power to the logic side of the 2 drivers. I would suggest that you make sure you have a big enough supply for the logic side of the drivers and use it to power the Arduino board. You may be putting enough load on the Arduino 5VDC that you are pulling the voltage level down at the Arduino and the drivers are nit getting quite the signal level they want. Or suply the Arduino through the USB (I am assuming you are probably working on code) and the stepper drivers with their own 5V supply with all grounds tied together.
1035  Using Arduino / Motors, Mechanics, and Power / Re: Stepper Question on: January 17, 2012, 06:30:08 pm
A schmidt trigger is used to clean up a signal. I think you might have meant an inverter.

You are going to get negative to positive, and positive to negative transistions of your step and direction signals from the Arduino so there should be no problem.
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