ds1620 temp sensor problem

krazyideas

I am useing the DS1620 to read some tempatures on some mosfets, so I will not blow up the mosfets.
I have the DS1620 working perfect in my bread board, but when I move it any distance away from the bread board via jumper wires about 24 inches long it will no longer work. I tried putting a 500 ohm in place of the 1000ohm but it made no difference.

I walked through all the wires very carefuly and the only difference of working and not working is the leanght of wires between the propellor chip and the DS1620

I'm a beginner programer, and I haven't a clue why this is happening. The leanght of wire is has never affected anything else I have worked on.

Thanks

krazyideas

I was reading through some other post and they fixed the problem but changeing the power to the DS1620 from 5v (which is what I had) to 3.3v and it fixed there problem. So I just tryed it and it works fine, now. I would still like to know what was going on there though any ideas.
the spec sheet said it was fine to run the DS1620 with 5 volts.

Why would it work at 5v close to the propellor but not far away? and why will it work close or far away from the propellor at 3.3v

krazyideas

how do I get the unsolved stat off my post

Franklin

The ds1620 is a 1-wire device and uses a communications protocol where the line is pulled high by the devices. if you have a 5v device being pulled "high" by a 3.3v device it might not work and the further away it is the less likely it will be.

Tracy Allen

The DS1620 is sensitive to noise on its power supply line. Try a capacitor of about 1 µF across the 5V supply right at the remote DS1620.

The DS1620 is an SPI device. Franklin, it is the DS1820 that is one-wire.

krazyideas

Thanks for the help guys

bomber

To remove the "unsolved" sign, go to the edit tab under your post. Then click Advanced. Next, change the prefix to whatever you prefer ("solved" or "no prefix").