NerdKits - electronics education for a digital generation

You are not logged in. [log in]

NEW: Learning electronics? Ask your questions on the new Electronics Questions & Answers site hosted by CircuitLab.

Support Forum » Oh No! Another Temp Sensor Problem..

August 05, 2012
by Medic8388
Medic8388's Avatar

Hey guys, I'm picking the nerd kit up again after not having a lot of free time in a while. I upgraded to the 328p and updated all of my make files (and project files) and downloaded the io_328p.h file as instructed in the update guide.

Everything comples correctly and I didn't have any issues with initialload or tempsensor loading onto the microprocessor. The trouble started when I run the tempsensor project, I am getting a temp reading of 499.51 (ADC 1023 of 1024) that does not change. I'm pretty sure the LM34 is ok, I ordered a new one when I got the 328p. I linked two photos (I hope...) showing my breadboard and LCD screen. Other than moving the LM34 a few rows down and using jumpers to connect it to the 328 (with the middle pin being bent like that it's kinda hard for me to see where to put it when I try to use the same rows as the 328) and adding two LEDs to let me know if I have power or if the 328 is in programming mode it is wired up per the instructions.

The tempsensor project file is the one that I was working with before I took a break from the nerd kit, it's stock except for an IF statement that prints a message to the LCD if the temp is above/below a set threshold and of course the header file for the 328.

Am I missing something here or is this maybe a faulty component somewhere?

Thank you so much for any help.

alt image text

alt image text

August 05, 2012
by Medic8388
Medic8388's Avatar

I wanted to update this and say that Ive checked my LM34 with my multimeter and it appears to be working ok.

August 05, 2012
by Rick_S
Rick_S's Avatar

It appears as though your LM34 is wired incorrectly. It also appears that you have wiring issues on the tempsensor side of the micro. If you are looking at the LM34 with the flat side facing you, the left side should connect to mcu pin 21 (row 18), the right to mcu pin 22(row 17), and the middle to mcu pin 23 (row 16). MCU pins 20 and 21 (rows 19 and 18) connect to 5V rail, and mcu pin 22 (row 17) to gnd. That's what it looks like from your photo anyway...

Rick

August 05, 2012
by Medic8388
Medic8388's Avatar

Omg... Im so embarrassed .... it actually wasnt wired up correctly :/... anyway, thanks for reading

August 06, 2012
by Rick_S
Rick_S's Avatar

No problem, I assumie it's working now?

August 08, 2012
by Medic8388
Medic8388's Avatar

Yes, it really helps if you dont count the pins backwards lol.

Post a Reply

Please log in to post a reply.

Did you know that NerdKits believes in the importance of a mixture of meaningful topics, clear instruction, and engaging projects? Learn more...