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1  International / Scandinavia / Re: Får ej reläna att reagera! on: April 16, 2014, 02:09:38 pm
Kul att det löste sig. Jäkligt lätt att man missar pinmode, har hänt mig flera gånger smiley

Angående EEPROM, jag har ingen Mega men det borde fungera.
Kolla att du har en hyfsat ny IDE version och inte någon gammal version.
2  International / Scandinavia / Re: Får ej reläna att reagera! on: April 16, 2014, 01:42:37 pm
Hej!

Jag ser inte någon kod som sätter HumSSR (pin 2) och TemSSR (pin 3) som output?
Lägg till följande under Setup():

Code:
pinMode(HumSSR , OUTPUT);
pinMode(TemSSR , OUTPUT);

/Olof
3  Community / Exhibition / Gallery / Re: Wireless temperatur sensor that is compatible with Tellstick Duo (Lib. included) on: April 01, 2014, 02:43:45 pm
Maybe you could modify the code so it prints out 1/0 in the serial monitor.
Then you can set the temperature and humidity to the same as in the picture and compare the output.

Another error source could be the fuses of your MCU (if you use a Attiny or other non standard setup)?
Double check that the delay functions are working correct  (the library uses the delayMicroseconds function).

/Olof




4  Community / Exhibition / Gallery / Re: Wireless temperatur sensor that is compatible with Tellstick Duo (Lib. included) on: April 01, 2014, 10:56:43 am
Hi Solem!

Sorry to hear that the sensor do not work.
Did you check out the site I linked to? http://lucsmall.com/2012/04/27/weather-station-hacking-part-1/
At the bottom you see a hand drawn picture with valid data.

/Olof
5  Community / Exhibition / Gallery / Re: Wireless temperatur sensor that is compatible with Tellstick Duo (Lib. included) on: March 16, 2014, 12:43:17 pm
Hi, thanks for your feedback!

The code from your link use the same CRC8 function (modified function from the  OneWire library) as I do.

I recorded the traffic with my occiloscope and the CRC bits  looked ok what I could see (compared my output with the picture from http://lucsmall.com/images/20130507-08-worksheet.png when I used the same temperature/humidity).
You are right that the Tellstick Duo don't care about the CRC bits but I send them anyway if you want to recive the data to a weather station.

By the way I have updated the library, fixed some major bugs (now handle negative temperature correct and changed some datatypes).
Also uploaded a new shetch that use a DHT22 sensor.
The row with the "OSCCAL " need to be removed or changed (use tinytuner to get the correct value if you use the internal oscillator).

My sensors (three) has worked flawlessly since I made them smiley


6  Community / Exhibition / Gallery / Re: Homemade function generator (XR2206 based) on: March 14, 2014, 09:09:05 am
Thanks, if you google xr2206 function generator you will find alot of builds with good documentation.

I can also try to answer any questions you have.
Some circuits are more simple (they skip sawtooth/pulse and don't adjust the output voltage) than others.

Examples:
 http://www.rhelectronics.net/store/diy-xr2206-function-generator-circuit-explane

http://www.instructables.com/id/Analogue-Function-Generator/#step1

/Olof
7  Using Arduino / Microcontrollers / Re: Is this a cheap source of ATtiny 45 on: February 25, 2014, 01:14:03 am
JoeN: First I suggested the Atmega8  as a low cost alternative to Atmega45/85 not Atmega328. The Atmega8 is a very good alternative (Ok 28 pin is a big drawback).
I also wrote that the low power version existed (Atmega8L).
Often 8KB is enough for a project, and how often do you need more speed than 16Mhz?

I don't know why you should buy them for the same price as Atmega328P when they cost 0,8$ (with free shipping!) on ebay.
I use Atmega8, Atmega328, Atmega1284 and Attinys, different MCU for different project.




8  Community / Exhibition / Gallery / Re: Electromagnetic Accelerator on: February 24, 2014, 12:53:14 pm
Just want to say that you have done a really cool project!

/Olof
9  Using Arduino / Microcontrollers / Re: Is this a cheap source of ATtiny 45 on: February 23, 2014, 04:31:12 am
Tim!

You can buy Atmega8 on ebay for 0,5£ with free shipping ($8.42 for 10 pcs.)

http://www.ebay.com/itm/10PCS-NEW-IC-ATMEL-DIP-28-ATMEGA8-16PU-/140730966675?pt=LH_DefaultDomain_0&hash=item20c4382293

The chip is 28 pin but you can blink alot of leds with it smiley
Much better than Attiny if you have the space.
Also consider the low power version Atmega8L if you don't want to power them with 5V.
10  Using Arduino / General Electronics / Re: Finished building a signal generator, but one annoying problem exists. on: February 22, 2014, 01:25:11 pm
I tried to adjust the probe. The result was a little better.

I also changed the pullup resistor that went to 5V to 47ohm. That helped a lot.
The signal was much better.

Some small spike remains, maybe my probe is not perfect.

Tom: I have a negative power supply. I am using a ICL7660 to get -5. My op-amp did not go down to 0V without the negative supply.

By the way: I have posted the finished function generator in the gallary.
http://forum.arduino.cc/index.php?topic=220331.msg1604096#new
It has been a fun project for a software guy like me, I learned a lot.
11  Community / Exhibition / Gallery / Homemade function generator (XR2206 based) on: February 22, 2014, 01:16:06 pm
Hi!

First I want to thank all the people that helped me when I asked questions about this project on this great forum.

This is my function generator based on a XR2206 IC. The XR2206 monolithic function generator IC is available on ebay for 3$.
The Arduino (ATMEGA8) handels the frequency counter.

I wanted to build a XR2206 synth but changed my mind.
I thought it would be better to start with something easy and learn how the XR2206 work before trying to control it digitaly.

The XR2206 is controlled with resistors and capacitors.
Frequency range is adjusted by changing a capacitor.
The frequency inside the range is controlled by a resistor (pot).

One problem (at least for me) was that the different waves had different voltage levels.
I ended up with two outputs. One 0-5V and a second adjustable 0-12V.

The knobs on the frequency generator controlls the following (from left to right):

1.   Frequency range
   1-10Hz
   10-100Hz
   100-1000Hz
   1000-10000Hz
   10000-100000Hz

2.   Frequency

3.   Duty cycle (Used by pulse and sawtooth wave)   

4.   Voltage level for second output

5.   Wave type.
   Square
   Pulse
   Sine
   Triangel
   Sawtooth

Part list:

XR2206 (Monolithic function generator IC)
ATMEGA8 (Counts the frequrency and controlls the MAX7219)
7-segment display with integrated MAX7219.
TL072 op-amp (used to adjustable voltage on second output)
ICL7660 (Produces negative voltage to the op-amp)

12  Using Arduino / General Electronics / Re: Finished building a signal generator, but one annoying problem exists. on: February 21, 2014, 01:07:16 pm
I followed the manual how to test the probe and the reference signal was perfect.

I can not understand where the negative voltage comes from, I also get >5V and that is also strange.

So it should be ok to "level shift" the signal the way I do?

I can not get a screen capture of my oscilloscope right now but found a picture when googling that looks similar after the signal get amplified.

Also the sine/tri, wave (different output pin) look good.
13  Using Arduino / General Electronics / Finished building a signal generator, but one annoying problem exists. on: February 21, 2014, 12:20:01 pm
Hi!

I have just finished building a signal generator, but one annoying problem exists.

I get a smal negative voltage. See thread http://forum.arduino.cc/index.php?topic=218142.0
The answer I got was that the negative voltage was a "glitch", nothing to care about.
Sure I can live with a tiny negative voltage as long the signal is 0-5V.

The problem is that my signal generator have two outputs.
One fixed 0-5V  and a second adjustable 0-12V.

That small "glitch" get amplified to a large negative "spike" by my op-amp.

I don't know how to get rid of the negative "spike".
The output of my signal generator IC (XR2206) is open collector.

Is it a bad design to pass a open collector output to a mosfet?


14  Using Arduino / General Electronics / Re: Gets strange voltage levels when converting 12V square wave to 5V on: February 16, 2014, 03:36:24 pm
Thanks Tom again!

So I can just ignore the whole thing?
I was afraid to damage the microcontroller if I fead the signal to its input.

15  International / Scandinavia / Re: Problem med PWM, transistor till led. on: February 16, 2014, 02:48:43 pm
Hej!

Du behöver ett "pull down" motstånd på utgången.
Sätt ett 10K motstånd ifrån basen på transistorn till GND.

Sedan är det en bra idé att begränsa strömmen på dina LED:ar annars kan dom brinna upp.

/Olof
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