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1  Using Arduino / Microcontrollers / Re: analogRead function in ATtiny chip on: April 29, 2013, 02:26:56 pm
I am sorry for reviving this topic, however, I must say I second this.
This pin labeling uncertainty is a bad apple in otherwise great thingy. :3

I am saying it after having debugged this code:

int analogReadPin=2
digitalWrite(analogReadPin,HIGH);//internal pullup on;
int analogValue=analogRead(analogReadPin);//read on pin 2

This code produces an error-it sets internal pullup thingy on DIGITAL pin 2, then attemps to read from ANALOG pin 2
correct code is:

digitalWrite(4,HIGH);//internal pullup on;
int analogValue=analogRead(2);//read on pin 2

Which is rather inconvenient.
I am sorry if it already has been solved, I am too busy to check it out at the moment and would forget about posting this once I am not. xD
2  Using Arduino / Installation & Troubleshooting / Re: Did I fry my ATMEGA? :/ on: January 02, 2013, 08:19:39 am
I forgot to mention-could it be that I was using ISP pins as output while running the sw with arduino connected to atmega?
3  Using Arduino / Installation & Troubleshooting / Re: Did I fry my ATMEGA? :/ on: January 02, 2013, 06:36:39 am
Is it possible I fried some pins on Duino instead? :/
Yes, that is possible if you were experimenting with the SPI lines. How was the LED connected? Did it have the appropriate current limiting resistors? If not, it may have fried the line drivers.

Well, I built myself an avr developing board. And it has resistors... They might be kinda small, but it has always worked until I connected the led to the SPI lines. :/ it's an rgb led and I wanted it to be bright, so I hooked up the smallest resistor according to some... led resistor calculating thingy. But, well it's some 70 ohms once and 100 ohms twice, but it failed when I connected Duino to it, yet the pins on Arduino are okay. I mean, at only point of time where more than 1 color was on, it was being programmed, sourcing energy from Arduino, pins of which are okay. I am confused. ;(

Edit: the Arduino is okay... But... how could I have fried the atmega32? I don't get it ;(
4  Using Arduino / Installation & Troubleshooting / Did I fry my ATMEGA? :/ on: January 02, 2013, 06:09:13 am
Hey guys... I was using Arduino as ISP to program my atmega32 in system. there was an rgb LED connected to mosi miso and sck. the LED was to be controlled from atmega. Now I can't program my mega. It says invalid device signature even after I disconnect everything. I tried reuploading the arduino as isp sketch to Duino. It uploaded, but no progress whatsoever. I tried avrdude -P COM3 -c avrisp -p m32 to test my mega without uploading anything, but it still says Device signature=0x000000 :/
Is it possible I fried some pins on Duino instead? :/
5  Using Arduino / Motors, Mechanics, and Power / Re: PC power source question on: November 22, 2012, 05:41:10 am
Firstly test one controller + motor at a time with the power supply, with Arduino powered from USB at first - fewer things to go wrong.

Adding 2k2 resistors in line in the logic signals from Arduino to L293D's will afford some protection to the Arduino and is a good idea when
first assembling things.

You can use a 9V or 10V regulator chip to drop the 12V down a bit before the Arduino power-jack - this affords some protection from drop-outs on the 12V power if the motors are pushing it hard.

What motors BTW?  Have you ensured everything can take the maximum current drawn from all the motors?

I made my mind-now I take the logic power from usb. I also used decoupling.
The current L293D chips are designed for is 600ma. I provide 12V at 24ohms-500ma. So I should be safe.
I have the L293Ds in sockets for easy replacement-is this a good idea? I mean, will the heat sink be effecient when it consist just of blob of metal on ground pins of the socket? The chips have heat protection, but still... Thanks for your reply, I really appreciate it.
(By the way-I have tested my setup with one motor so far. And it seems to run fine, I am just a bit concerned about the heat dissipation.)
6  Using Arduino / Motors, Mechanics, and Power / PC power source question on: November 20, 2012, 10:35:46 am
Hey there. I am building a CNC, pretty much from scratch. The "driver" for 3 steppers I made consists of 3 L293D H-bridges and 2 74HC595 shift registers. Purpose of the shift registers is just so that I don't have to use 12 wires going from the Arduino. I modded an old PC power supply, I just cut off the wires, put some connectors there for easy access and attached 2 bulbs for dummy load. I am now wondering-is it safe to just connect all the grounds and provide 12V to the motors across the bridges? Also, it might be more convenient to use the 5V power source output for logic, but it's recommended to use 7-12V to power Duino. And 12V seems to be the upper limit when things are getting inefficient. So... what should I do? if I connect +5V from Arduino to all the logic chips and +12V to the VSS of the L293Ds and connect the power supply ground to the Arduino ground, am I good to go? Also, will I need decoupling? And if so, 100uF capacitor in parallel with each chip should be enough, right?
7  Using Arduino / Project Guidance / What's so great about stepper drivers? on: August 16, 2012, 08:13:14 am
Hi there, I was just recently looking at the RepRap project and found out it is using dedicated stepper driver chips. However, I recall having seen stepper motor connected to Duino just using 2004 darlington array, or 293D h bridge. So I just wanted to ask-what's the advantage of using stepper control circuit? Using less Duino pins? If I'm not mistaken, it's not common to use any sort of hall-effect feedback from steppers, so that leaves you with needing pins as output only-and in such case, one can use 74HC595 or similar shift reg, right? Or is it processing power? You basically only need to drive 1 or 2 steppers at the time if you optimise the code. :/So why the drivers? They are expensive and I don't see much pros.
8  Topics / Device Hacking / Re: double phototransistor from old mouse on: August 05, 2012, 01:08:22 pm
Nevermind, solved it. Seems like this one was actually common collector type. Weird.
9  Topics / Device Hacking / double phototransistor from old mouse on: August 04, 2012, 11:04:45 am
Hello, I've been trying to make a printer out of computer junk using old cd drive tray mechanism for movement and old optical mouse to get the movement information. But turns out that the mouse always says: "Hey, you moved by 20 points!" But what I need is a precise and more importantly REAL TIME counter. So I decided to take a different approach and use dual optointerrupter out of a ball mouse.
After some research, I've learnt that those are in fact ir photodiodes and dual phototransisors with common cathode. (Or emmiter, if you wish so). I've connected an IR phototransistor to my Duino before, but I'm not sure about this special stuff. Do you guys think this is the way to do it?
If not, how should i do it? I don't wanna destroy my phototransistor.  smiley-confuse
10  Community / Bar Sport / Re: Stupid schematics on: July 05, 2012, 10:03:49 am
Hi there, I couldn't find the capacitor, so I didn't put it there, it didn't seem to serve any purpose, anyway. Furthermore, wouldn't this cause the cap to blast voltage back into the poor duino? O_o.
11  Community / Bar Sport / Re: Stupid schematics on: June 30, 2012, 02:18:31 pm
OK, I've done it finally. I found the lead-suckin-wire-thingy, so it wasn't that difficult after all. smiley-grin
12  Community / Bar Sport / Re: Stupid schematics on: June 30, 2012, 12:41:31 pm
Often it is clear that is what they are doing because you will have pins on three sides or more pins on one side than another. 
Unfortunately this wasn't the case. Also-I just quickly checked the pin layout displayed on top with the schematics-And because of the pins at the left side, they looked the same. Yeah, but thanks anyways. I might be able to repurpose some of the soldering, but I seem to be running out of the soldering iron. Wish me luck. smiley-grin
13  Community / Bar Sport / Stupid schematics on: June 30, 2012, 10:43:20 am
I just spent few hours nicely soldering together this circuit. Now I realised that the pinout on the schematics doesn't correspond with actual chip pinout. ANGHHHTTT! ALL CAPS RAGE!!!! Yeah, so that's it. Feel free to learn from my fail.
EDIT: IF you know of any shiftreg with pin layout that corresponds with the one shown on aforementioned link, I'd be more than glad.
14  Using Arduino / Project Guidance / Re: CNC with servos-is it even possible? on: April 28, 2012, 08:52:37 am
Hey, that's what I call an idea! I could probably paint the sheet of paper with some lemon juice and then burn  it so that it turns brown. CHEAP PRINTING FTW! smiley-grin Btw I didn't even realize that cutting through the material under angle would be an issue, shame on me. :X Thanks so much, guys!
Edit: but... the laser doesn't seem powerful enough to burn anything but black plastic. Stupid. smiley-sad
15  Using Arduino / Project Guidance / CNC with servos-is it even possible? on: April 28, 2012, 07:21:41 am
Hi guys, this might be an utter nonsense, but do you think, in theory, it would be possible to do a servo rig for high power laser and then let this laser cut into, say, wood? I mean, rig it like shown here: Also, although I already sort of know answer to the following question, the urge to ask it is too hard to resist: Do you think DVD burning laser would do the trick? Because I've seen a dvd laser cutting balsa. And if so, would I need any fancy adjustable optics? If it is possible, I'm gonna make myself a cute pocket cnc ^^. Thanks for all answers!
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