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16  Using Arduino / Project Guidance / Ok have my temp sensor working , how can I hook it to my 4 x 20 screen?? on: October 06, 2012, 12:36:07 am
I have now got my 18B20 temperature sensor working with my arduino.  The temp display at the moment is only on the computer at the moment via the serial monitor.

How can I now make this portable via using my 4 x 20 lcd display?  it is a ic2 display.  Are there any tutorials I can follow that will show me how to display the
temperature on the lcd screen?

17  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 25, 2012, 05:08:35 am
dc42, wow great link, and I can now browse them all via the rds(on) voltage.  cool.


18  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 25, 2012, 04:55:46 am
yeah I agree I have been chasing my tail looking up numbers and I too think they are limited in what they sell.

19  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 24, 2012, 11:44:44 pm
http://www.jaycar.com.au/productView.asp?ID=ZT2225

there is a pdf data sheet there
20  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 24, 2012, 09:50:33 pm
how about a BUZ71
www.jaycar.com.au/images.../BUZ71.PDF

has a vgs of max 4v

should only need one as it can switch 50v  14A

ohh, and a heatsink
21  Using Arduino / Project Guidance / Re: DS18B20 Temp sensor not working with arduino? on: September 24, 2012, 07:35:29 pm
doh!  just testing you lot. lol.   will have another go when i get home from work
22  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 24, 2012, 06:03:37 pm
yeah righto , totally confused now, lol.

This is where I get my parts from as the hve a shop in town.  http://www.jaycar.com.au/index.asp

Can some one find me a suitable mosfet, the one you mentioned the IRL540 is not listed (I do not think) . 

23  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 24, 2012, 04:55:55 pm
ahh, so instead of being the 120deg as mentioned before with no heatsink, with the heatsink it would only be 38deg then?
24  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 24, 2012, 04:46:33 pm
The one that is smoking is a to220 size, but just no heatsink.

How did you work out that the bulb has a resistance of 3ohm when fully lit?

What is that 15x15x8mohm calculation called, so I can look it up and study it a bit.

I am aware you can also calculate how much temperaure a heatsink will suck off the mosfet. But what size do I get 1" x 1" size?
Ahh, just had a look at it in a catalog and it says a degreeCelcius/W
example there is one here that is for a to-220, that is 19degree celcius/W (watt I assume)

How does this work then?  It will suck away 19 degrees for every watt of power?
Then if I look at the much larger heatsinks they are rated at like 1.4degrees celcius/W, I know they will take the heat away better than the smaller ones but they have a lower temp/watt value???
25  Using Arduino / Project Guidance / Re: DS18B20 Temp sensor not working with arduino? on: September 24, 2012, 04:32:55 pm
Ok here are some pics.

26  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 24, 2012, 04:23:59 pm
Okay I have made up a diagram, and have noticed a wrong hook up.  You will see a red line where it is wrong.

Yes it is connected to a PWM output on the arduino.

I have a smaller mosfet to turn the bigger one one, like a darlington pair I guess.

See the schmatic.
27  Using Arduino / Project Guidance / DS18B20 Temp sensor not working with arduino? on: September 24, 2012, 09:02:06 am
My temp sensor is not working with arduino.  I have it hooked up right (I think). When hooked up the on board arduino led goes very dull, and then the USB connection drops out and the arduino is no longer connected to the PC.

When I pull out the ground or the 5V wire from arduino , the led lights back up and the board reconnects to the PC.

I am following these instructions: http://bildr.org/2011/07/ds18b20-arduino/

It is like it sucks too much power???

28  Using Arduino / General Electronics / Re: How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 24, 2012, 08:11:49 am
Yes I do remember reading something about that.  It is getting about 12.56v to turn it on.  Which is what is switched on via the smaller mosfet behind it.

All I have to work with is that 12.5 volts.  Should I source a better suited mosfet?
29  Using Arduino / General Electronics / How come my MOSFET was a "smoking", I thought it was rated high enough. on: September 24, 2012, 07:41:03 am
I have used a small mosfet that will switch via the 5V signal from arduino into another larger mosfet that is hooked to a 12 50W halogen down light.

The bigger mosfet is an IRF3205    http://www.irf.com/product-info/datasheets/data/irf3205.pdf

Here are the main stats:
Continous drain current 80A at 100deg., 110A at 25deg,  pulsed drain current is 390A
Power dissipation , 200W
Gate to source voltage +-20

If my light is 50W, don't I have 150W left to play with? 

I did not have a heatsink on it.
Do you have to have a heat sink bolted to it always?  I thought you can use mosfets with out heat sinks at lower power levels??





30  Using Arduino / Programming Questions / Looking for tutorial on how to make a menu for my arduino, and then use buttons on: September 24, 2012, 05:59:23 am
Looking for tutorial on how to make a menu for my arduino, and then use buttons to access that menu and turn lights & motors on/off etc.

There must be a easy to understand tutorial for a noob somewhere online???
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