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General Electronics / Re: 433Mhz wireless problem
Last post by crojai - Today at 08:22 am
Thanks for the reply. So far I can say this:

1- I have AVCC and VCC connected to the 5v rail.

2- The only caps I have connected to the mega328 chip are two 22pf connected to GND and Pin9 and the other to GND and Pin 10.  The crystal is connected to Pins 9 and 10 on the chip (labels are XTL1 and XTL2)

3- I checked if AVCC and VCC were connected to anything when the chip went in backward. Luckily, the wouldn't have been connected to anything. I guess that's why the chip survived.

4- This transmit module is DATA, VCC and GND. Connections are good. Wired same way on the breadboard.

5-I'll try the suggestion for pin7 and the voltmeter tomorrow for sure.

One other thing. This morning I found the reset button was wired the wrong way, ie it made a closed connection to the reset pin and ground instead of an open connection. Another careless mistake.  Anyhow, I just cut it out of the circuit (little frustration got to me!). Ordered some new buttons as that was my last one.

Made a rough sketch of circuit attached..

Thanks again.
Hardware / Re: LCD TFT ILI9341
Last post by uwefed - Today at 08:13 am
Che Arduino usi e che libreria?
Ciao Uwe
Sensors / Re: Analog reader head.
Last post by Riva - Today at 08:12 am
yes i want a one track reader head , and i have a diagram of a circut someone used for something simillar , i tried to do what you suggesting by reading the output of the reader , it isnt working at all theres some kind of emi field being generated when its on and i cant get any data out of it with out using there software and using a different reader type isnt an option for this project , the reader in question has this head so thats why im trying to interface directly to it
Can you post or link to the circuit your mention. Also when you say 'there software' what software and who are you referring to?
Why does it need to be this reader type?
What are you trying to do that an off the shelf reader cannot do for you?
Project Guidance / Re: Thesis Title
Last post by ChrisTenone - Today at 08:05 am
This is what they call "the internet of things" right? Where you use controls on a web page to activate electrical machinery in the real world?

I'd play off that IoT buzzword for your title. It's doing what they call "trending".
What are you trying to do here?
First I read the status
delay for a little bit
send the message using Nick Gammon's lib (
Then (from the same web-page): The first loop waits for the hardware chip's buffer to empty, at the same time setting the "transmission not complete" flag. The second loop waits for the final byte to be clocked out by the hardware.
Then disable sending messages.

Are all of the UNO's wired the same or is the first one different?
All the slaves are wired the same way, but the master is wired differently (using other pins for communication)
1. Actually those vars are accessed via assembly routines defined inside. Below is code of one function:

Code: [Select]
bool  i2c_start(uint8_t addr)
  __asm__ __volatile__
     " cli                              ;clear IRQ bit \n\t"
     " sbis     %[SCLIN],%[SCLPIN]      ;check for clock stretching slave\n\t"
     " rcall    ass_i2c_wait_scl_high   ;wait until SCL=H\n\t"
     " sbi      %[SDADDR],%[SDAPIN]     ;force SDA low  \n\t"
     " rcall    ass_i2c_delay_half      ;wait T/2 \n\t"
     " rcall    ass_i2c_write           ;now write address \n\t"
     " ret"
     : : [SDADDR] "I"  (SDA_DDR), [SDAPIN] "I" (SDA_PIN),
       [SCLIN] "I" (SCL_IN),[SCLPIN] "I" (SCL_PIN));
  return true; // we never return here!

2. As can be seen var addr is accessed via assembly function. (i don't know how it happened, but code works). Also writer had added last statement "return true", to fool the compiler so it don't generate any warning. however code return in assembly part inside.

3. On compiling there is warning that addr is unused. So I think adding another statement before
return function will remove the warning.

4. However I didn't made any changes since I didn't read its license terms till now.
Microcontrollers / ATTinyXX Serial Communication ...
Last post by babsndeep - Today at 08:03 am
Hello Everyone,

This is a kind of a long post, Sorry about the lengthy text, but please bare with me :)
Any Help is much Appreciated.

First of all, I've been unsuccessfully trying to get my ATTiny85, ATTiny44A to display text to the Serial Monitor using Arduino Uno as an ISP. I have the correct Baud rate in the program of 9600, I am using the built in SoftwareSerial library. I've even burned the 8Mhz bootloader on both ATTiny85, and ATTiny44A with no luck of being able to display text on Serial Monitor.

I am using the follwing cores for the ATTiny's:

When I have the following code uploaded to the ATTinyXX, the Serial Monitor just displays a bunch of garbage text, for example "yoyyuou/u" with two dots on top of both "y" and "u".

So my questions is, what am I doing wrong?

Moving on, the reason I am trying to get the ATTinyXX's to work with Serial communication is so that I can use them with a BT module to transmit data to an Application, Since I only need a few I/O pins for peripherals, I figured ATTinyXX's would be a good idea, However, given the difficulty I am having with getting them to work, I would like to explore alternatives, which brings to my second question, What alternative MCU can I use instead of ATTinyXX's (incase they don't workout)? the main thing I need is for the MCU's to be able to pass on the data to the BT module that will connect to a mobile App using TX, RX pins. I was thinking atmega168? atmega328p?

Any suggestions would be much appreciated, preferably stating Pro's and Con's from personal experience and use.

Sorry again for the long post, I would really appreciate any help/suggestions/feedback as I've been banging my head for a few weeks now trying to get over this hurdle.

Thank You   
Displays / Re: Noobish question
Last post by cgroshko - Today at 08:02 am
Funny that was almost the same answer, word for word i got on the AVR forum lol. Should have explained myself a little better essentially I'm cleaning out boxes of stuff i don't need, so I'm trying to determine if the LCD's are trash or if they are usable with moderate effort. I'm not interested in "redesigning the wheel" i just like to recycle ;)
Hello NZJohn, what type of switch works with Your ethernet shield? Brand, model etc.. And what "type" of ethernet shield do You have? I mean markings from han-run sticker. Thanks!
Project Guidance / Re: Girls?
Last post by ChrisTenone - Today at 07:57 am
Too much emphasis on competition and winning IMHO

It is in our genes and it is what has got the human race in the mess it's in. We should be taking every possible step to thwart that aspect of our genes.

That genetic competition has caused the majority of human suffering is debatable. Some people blame desire for material riches, while others think that it is the belief that only adherents to their own spiritual philosophy be allowed to thrive.
As for there being too much competition in our engineering classes (this style is only used in the first two, introductory, classes), I can compare it to our own classes of fifteen years ago, when we taught it as a traditional 'lecture, repeat, assess' class. Only boys took those classes. Now, as I said, we have a pretty even mix of boys and girls. Our engineering competitions are not not violent, nor do they keep those who do not win from any of the spoils (ie. learned knowledge). We also have an element of cooperation - teams work best (and win) when they have a high degree of cooperation within the team. As it turns out, girls - like boys - are highly motivated when they believe they can win.
Teams get shuffled for every project, so each student has a chance to work with every other student. At first, the students want to segregate - by gender and ethnicity. By changing the teams around, the students learn to work with people very different from themselves. The boys learn that it is not disadvantageous to have girls on their team.
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