How to use the 4 extra analog ports for thermistor input.

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Flateric
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How to use the 4 extra analog ports for thermistor input.

Post by Flateric »

I have, as I know some others do also a Rambo board with 4 burned out thermistor inputs.

I was told on IRC last night that it is possible to use the "analog ext" pins (directly beside the thermistor ports) as 4 new additional ports for thermistor input. They may not be burned out.

Does anyone know how to map these pins for this use?

This would be spectactular if someone could show how, or atleast point me in the right direction towards this solution. The fellow on IRC had apparently successfully performed this task, with the help of a voltage divider resistor? And before I could get to much more out of him he logged off unfortunately.
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Re: How to use the 4 extra analog ports for thermistor input

Post by mhackney »

Wow, you too huh! I assume you have to replicate the voltage divider circuit on these pins. The schematic on the reprap wiki has the details. It also has a link to the complete pin mappings for RAMBo.

I just got some of the tiny caps to see if that what popped. If so, the fixes easier. If not, it is probably as Polygonhell suggested, the Arduino itself. I'll likely undertake replacing that if necessary. The hard part is getting the old part off but tiny nippers do a good job. I've revived a lot of electronic devices replacing surface mount packages so it can be done.

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Re: How to use the 4 extra analog ports for thermistor input

Post by Flateric »

Could you share a link to the pin mappings for Rambo man! Thanks.
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Re: How to use the 4 extra analog ports for thermistor input

Post by mhackney »

I would and will except the RepRap.org wiki is being cantankerous and not loading now. This seems to happen fairly frequently.

Pin assignments are here: http://reprap.org/wiki/Rambo_development

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Re: How to use the 4 extra analog ports for thermistor input

Post by geneb »

It wouldn't surprise me at all to find out the RepRap wiki is hosted on an aging Pentium MMX 166 machine, sporting a 10MB NIC and a 0.99 Linux kernel... Its performance supports this hypothesis. :)

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Re: How to use the 4 extra analog ports for thermistor input

Post by Flateric »

I noticed it is not accessable very frequently. VERY.....
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