Monochron Temperature Sensor

[adafruit_support_bill]

Looks like it is not recognizing your FTDI cable. Are you sure you have the right serial device selected in the tools menu?

[edc1591]

Yup, 100% sure.

[adafruit_support_bill]

Try disconnecting and re-connecting the USB end. The FTDI cable should be recognized by your computer regardless of whether anything is connected to the serial end.

[edc1591]

Still getting the same error. I tried a different USB port too.

[adafruit_support_bill]

Can you go back to the last configuration that worked? (prior to the processor swap)

[edc1591]

Yep, everything works fine when I put the processors back.

[edc1591]

OK, I tried using the monochron's processor on the Arduino PCB and it doesn't work either (neither pin 15 or any others). So I guess the problem is the processor. Is it possible I was sent a defective one?

[adafruit_support_bill]

Given that the display and other functions work, I don't think it is a bad processor. Looking closer at the design files, I see that the Monochron's processor clock is configured differently than the Arduino's. That explains why a direct swap doesn't work.

[edc1591]

So, if the processor is fine and the sensor works on the Arduino, it sounds, to me, like it's a software difference between the Arduino and the monochron that is causing this not to work. Does that sound right? Is that possible?

[adafruit_support_bill]

I suspect it may be the clock difference. The DHT library uses a 'bit-banged' protocol and the timing will be different with the different clock rate.

[edc1591]

Would it be possible to modify the DHT library to work with the monochron? Could you possibly point me in the right direction?

[adafruit_support_bill]

Looking at the code, all the timing is done with millis(), delay() and delaymicrosecond(). These should work as long as the correct clock frequency is specified in the boards.txt file for the Monochron.

The other thing to check is the pin mappings in pins_arduino.c. Make sure that pin 24 is mapped the same as the Arduino.

[edc1591]

So, I don't need to modify the DHT library?

I've attached the monochron directory of my hardware folder. Could you take a quick look to see if I made the correct modifications?

monochron.zip

(215.63 KiB) Downloaded 45 times

Thanks

[adafruit_support_bill]

So, I don't need to modify the DHT library?

That is what it looks like. But it is possible there may be other, less obvious timing dependencies in there.

Could you take a quick look to see if I made the correct modifications?

Unfortunately, we can't realistically get involved with debugging modifications to unsupported code. You might try contacting the people that developed the Arduino port of the Monochron.

[edc1591]

It looks like the DHT library was the problem. I'm using this library now (http://arduino.cc/playground/Main/DHTLib) and it works!

Thanks so much for all your patience with this