How to change thermistor settings in sprinter?

Hi,

I have woody, my reprap printer almost running but have issues with some things that I hope someone can help with.

Number one is my hotbed not heating up and reading 357 degrees in pronterface.

I have been told by the supplier of my thermistor to change the settings in sprinter to read the b number as 4000 and I have no idea how to do this.

I am also using heringbone gears and just found out I need to change the extruder settings in sprinter to reflect this.

I have done some searching and really need some very basic instructions on how to change the sprinter settings in my sanguinololu 1.3 board.

What I need is links to download everything I need and then very detailed instructions on how to change the settings and then how to send these changes to my circuit board.

A video on youtube would be great. I have found one about sprinter but it moves too fast and I get lost in the first 30 seconds.

I am so close to printing but these issues are getting really frustrating.

Any help appreciated

You need to configure, compile and upload a whole new firmware. I assume you got Sprinter preloaded on your electronics and will need to start from the beginning.

Go to Sanguino.cc/useit and follow the instructions for your OS. Use an older version of the Arduino environment, 1.0 has issues but 23 works.

Download a copy of the Sprinter source, or other firmware if you like.

Unpack the source somewhere and open the .pde file in the Arduino environment.

Open configuration.h and work your way through the file making changes to suit your machine. The defaults should suit a standard Prusa for the most part. If it makes no sense at all to you, look for a beginners C tutorial, but the file is pretty self explanatory. Hopefully your thermistor is one of the common types and you can just define the thermistor variables appropriately, if not you will need to generate a new table and include it in thermistortables.h. I'm not quite sure how to do that, but the program that generates the tables is written in python so start by installing that.

When the firmware is configured, select Sanguino from the tools->boards menu, select the com port, hit the upload button.