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1  Using Arduino / Displays / What's the simplest 128x64 monochrome display for displaying video? on: February 21, 2014, 02:04:00 pm
I'm currently trying to display some data over serial to an ST7920 display. The problem I'm facing is that the display is weird to manager (it's a character/graphics hybrid) and I'm really considering an alternative.

I only want to be able to print a framebuffer from Arduino onto it, as fast as I could. Does anyone have an alternative suggestion? Instructions/Datasheet/Code is greatly appreciated!
2  Using Arduino / Motors, Mechanics, and Power / Re: Motors make IR sensors go nuts on: June 25, 2013, 05:11:18 am
I tried powering the Arduino using a 9V battery and the motors using my robot's batteries and the problem was eliminated. The question remains though, how can I filter the remaining noise and use the same batteries?
3  Using Arduino / Motors, Mechanics, and Power / Motors make IR sensors go nuts on: June 24, 2013, 07:07:23 pm
I currently use three IR sensors bought from eBay on my robot. The sensors are the same with this product: http://www.dfrobot.com/wiki/index.php?title=Adjustable_Infrared_Sensor_Switch_(SKU:SEN0019). They are digital IR sensors that output a TTL signal depending on whether they are blocked or not.

When I first bought the parts, I used to have problems, mostly noise that made the sensors switch "on" and "off" when the motors were running. This is an obvious problem and I solved it using 3 capacitors on each motor (4 total). Now I'm facing another problem. When the motors stall or are stressed (for example when I load them a bit more or stop it) the sensors switch to "on", reporting that an object is present. This is wrong and makes the robot go nuts (on the other hand it has some serious dance moves!).

The question is, should I apply more filtering (and where) or is this a battery issue? The motor controller is the classic L298, I will try and separate the motor power from the board/sensor power and report back. I really do not want a different supply, so what can I try? By the way, the sensor's LEDs (that show if they detect an object) seem to flicker when the motors are stalled. Should I try and change the PWM prescaler of the motors?

EDIT: I didn't post this to the sensor subforum because I think it more of a motor problem.
4  Using Arduino / Programming Questions / Re: Change/Rotate string every N seconds on: June 03, 2013, 02:41:14 pm
I should have been more accurate with my original description! I actually want to execute different functions at those intervals. Let's call them A(), B() and C(). How can I do this? One quick answer based on HazardsMine's answer might be using function pointers, but I have no past experience.

Based on the Blink (no delay) sketch, how can I do this? I understand that each method will be executed after N seconds but how do I cycle between them? I guess that they will overlap, which is something I don't want.
5  Using Arduino / Programming Questions / Change/Rotate string every N seconds on: June 03, 2013, 02:05:37 pm
I'm trying to find the best way to change a string message after some seconds. What I'm trying to achieve is show message A for 5 seconds, then message B for another 5 seconds. How can I approach this on the Arduino?
6  Using Arduino / Installation & Troubleshooting / Re: Arduino MEGA2560, "verification error, first mismatch at byte [...]" on: June 02, 2013, 12:24:16 pm
Well, I wired up my Arduino Duemilanove, flashed ArduinoISP, installed a capacitor to disable the reset and wired up the two boards. I tried uploading the .hex file both through avrdude and inside the Arduino IDE but I always get:

Code:
avrdude: verification error, first mismatch at byte 0x1e000
         0xff != 0x0d
avrdude: verification error; content mismatch

What am I missing here? Any lock bits that need to be disabled first maybe?
7  Using Arduino / Installation & Troubleshooting / Re: Arduino MEGA2560, "verification error, first mismatch at byte [...]" on: June 02, 2013, 11:56:22 am
No, but I do have many bitmaps that contain 0xFF. Commenting out those bitmaps does not trigger the bug. I will try to upload the new bootloader and see what happens. Thanks a lot!
8  Using Arduino / Installation & Troubleshooting / Arduino MEGA2560, "verification error, first mismatch at byte [...]" on: June 02, 2013, 11:35:04 am
I'm getting this weird error on both my Megas. Most of the sketch data is XBM bitmaps, so I guess this is what it triggers this bug (long sequences of repeated data). Has anyone else experienced this bug/glitch? I guess there is something wrong with avrdude.
9  Using Arduino / Displays / Re: Help add support for HT1632 in u8glib on: June 01, 2013, 09:53:53 am
Everything works fine! I also setup multiple display (just tested 2 displays for now) and everything seems fine.
10  Using Arduino / Displays / Re: Help add support for HT1632 in u8glib on: June 01, 2013, 04:48:58 am
Thank you! I'm really excited to get this working smiley-grin When do you plan to release a new version with the driver included? I want to map custom pins but don't know what changes I should make to the driver file.
11  Using Arduino / Programming Questions / Re: Timer 1 on ATtiny25/45/85 (CTC mode) on: May 31, 2013, 07:39:29 pm
If all you want is one second timer, you could set up your timer interrupt with a top of 250 and a prescaler of 8.  Then you could count down to 20625 and your code would be called at exact one second intervals.

I have setup the timer as you suggested. Prescaler 8, top 250. This is my ISR routine:
Code:
ISR(TIMER1_COMPA_vect) {
  if (counter == 0) {
counter = 20625;
PORTB ^= (1 << PB0);
  }
  counter--;
}

It seems that the LED is flashing with periods longer than ~2.5s (I'll have to get my multimeter to be sure). Can you please explain how you calculated 20625? 16500000/8 equals 2062500

EDIT: I got it! The ISR needs to count to 8250. That's 16500000/8/250! Thanks everyone smiley-mr-green
12  Using Arduino / Displays / Re: Help add support for HT1632 in u8glib on: May 31, 2013, 03:42:01 pm
Just a quick question: Doesn't u8glib support multiple displays? I'm pretty sure I have seen an example that multiple displays are used at once as one! I can't find it on the wiki though.
13  Using Arduino / Displays / Re: Help add support for HT1632 in u8glib on: May 31, 2013, 02:49:49 pm
If you need testing, I'll be glad to help!

By the way, the framerate seems unbelievable. Drawing white and then balck fullscreen boxes makes the screen tear due to the chip's refresh rate.
14  Using Arduino / Displays / Re: Help add support for HT1632 in u8glib on: May 31, 2013, 01:53:28 pm
Here you go: http://imgur.com/QNmhuju

Thanks for the cooperation! Keep up the good work smiley-grin
15  Using Arduino / Displays / Re: Help add support for HT1632 in u8glib on: May 31, 2013, 08:42:40 am
I have 4 of these displays and I'm planning on using them as one, 48x32 display. Do you want a picture of the big one or the small 24x16 one? It's hard to display anything readable on the 24x16 display.

Again, thanks for making this possible!
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