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61  Forum 2005-2010 (read only) / Troubleshooting / Re: Before I buy an Attiny 85........ on: December 09, 2010, 11:08:48 am

I came accross this - never done it myself
62  Forum 2005-2010 (read only) / Interfacing / Re: DS18B20 and long distance on: October 06, 2010, 02:41:07 pm
are you using the sample code?

  ds.write(0x44,1);         // start conversion, with parasite power on at the end
  delay(1000);     // maybe 750ms is enough, maybe not
  // we might do a ds.depower() here, but the reset will take care of it.
  present = ds.reset();

you might try turning the parasite power off if you're not running in that mode

and try playing with the delay()

I have shorter runs
I had issues trying to run parasite and non-parasite at the same time so I went to the non-parasite mode for all mine - running 5
I was also able to reduce my delay() as it appeared to be needed more to charge up the parasite mode - but I did still needed a delay as I would get a drop out every now and then until I bumped it up a bit
63  Forum 2005-2010 (read only) / Interfacing / short circuit protection with one wire ds18b20? on: December 09, 2010, 12:54:05 pm
short circuit protection with one wire ds18b20's

I have one ds18b20 in the ground/soil and another one in an outdoor pond - I would expect that some day they will shortout...

I couldn't find anything in:

A google search came up with:;start=all

"If you are going to have any kind of wire run I would suggest looking at some of the ESD protection variations (resistor in series with IO pin and 5.5v Zener diode to ground) to keep the stress down when bad things happen."

So the resistor and zener diode looks simular to one of the three methoids in the grumpy_mike

I run 5v, gnd, and input (all from the arduino pins - power from 9v wall wart to arduino) to each one wire sensor with 1k between the 5v and input.

what are other's using and found to work for short circuit protection with one wire networks



64  Forum 2005-2010 (read only) / Interfacing / Re: DS18b20 Advice on: December 04, 2010, 05:59:32 pm
It would skip/not find the device
65  Forum 2005-2010 (read only) / Interfacing / Re: DS18b20 Advice on: December 04, 2010, 11:20:21 am
yes - tied them all together and then to the arduino. I used some terminal screws for +5,grd, data. Put my resistor accross and then ran jumper wires to the arduino pins.

I also used lower resistor values as I read that it could help for longer distance runs (and it seamed to help in my case as well)

I have a unslung nslu2 that polls the arduino (ethernet) and writes the data to a log file every 5 minutes - so by unstable it would sometimes read/record the temp and sometimes couldn't find the devices. The arduino wouldn't crash just that the one wire devices didn't return a temp at times but would at other times.

66  Forum 2005-2010 (read only) / Interfacing / Re: DS18b20 Advice on: December 04, 2010, 10:10:21 am
I believe that the lan is the recommended way - but I ran mine in star mode. I had 5 working (runs of between 10 to 30ft each) but when I added the 6th one on a 60 foot cable the one wire network got unstable. So I put the 6th one on a different digital pin.
67  Forum 2005-2010 (read only) / Interfacing / Re: Problem with energy monitor on: November 16, 2010, 07:24:25 pm

try switching to an analog pin and then do a serial.print on it's values with a loop - see if you get some different values during blips

also use an ir against your sensor and see what values you get

i used a different photo sensor (one from radio shack I think the 276-142) and had issues with sunlight washing it out with ir light at noon - my meter is outdoors.

made a cover/hat with duct tape and that fixed that issue.

I also spend a bunch of time playing with the resistor values - I don't know how yours is wired up.

I ended up using a running averages (on the analog values) and then look for drop and raise to trip the count - with a bit of de-bounce.

It took me hours and days over several weeks of playing around with it to get it working but it's been working well for a few months now.
68  Forum 2005-2010 (read only) / Interfacing / Re: Guitar preamp for use with Arduino- 0 to 5V output on: November 04, 2010, 11:02:32 am
reading his blog he states:

So far, I have used this circuit to experiment with the Arduino Realtime Audio Processing writeup that can be found here:

And it sounds MUCH BETTER with this preamp than with the setup that is described on their website.
69  Forum 2005-2010 (read only) / Interfacing / Re: How to get rid of double readings from a LDR on: October 29, 2010, 12:42:31 pm
debounce it: time the blink (on time) use that time to make sure your outside the on blink before counting again
70  Forum 2005-2010 (read only) / Interfacing / Re: house water main supply pressure psi- best way? on: October 06, 2010, 08:16:33 am
thanks all for the reply's

the Honeywell item is interesting - but the spec sheet says air/gas - there's like 10000 listed so I'll keep looking

anyone found a cheap 3/4" meter?

correct I was interested in detecting different device events with the pressure profile - I read a short news/pr article and thought it was interesting - I think the article was actually on high freq noise profiles with starting and running of electrical devices - but that's way beyond my capacity - in digging I found that it also applied to indoor pumped devices but with pressure - and that sounds like it's within my capacity... and there was also one with dp sensors in a central hvac filter to detect people entering and leaving different rooms via pressure change profile responses from the return ducts (I had no interest in that one)

looks like it's the <$3 piezo to see if my main water pipe gives any kind of feedback to water events. I have pvc and cpvc and wonder about damping...
71  Forum 2005-2010 (read only) / Interfacing / Re: house water main supply pressure psi- best way? on: October 05, 2010, 06:18:39 pm
thanks for the input!

so far the cheapest that I've found is about $80 to 125  and that's more then I'm willing to spend at this point with out having a clear plan but 125 bucks is cheaper then a doctor's visit!

I've never seen anything over 65psig at my house the doz times that I've checked - but I'm a bit elevated and don't know what the water dept does when I'm not checking...

I'll keep looking for something with a higher range, safer and cheaper.

72  Forum 2005-2010 (read only) / Interfacing / house water main supply pressure psi- best way? on: October 05, 2010, 08:46:31 am
Looking to get pressure off my house water main supply, I saw an article on using pressure profiles to determine what device is using water. Thought it would be fun to try counting toilet flushes  :smiley

Googling around it seems that an oil pressure sender might be a cheap way to do this - but I didn't find a whole lot of details other than the idea.

Does anyone have suggestions for an car oil pressure sender - I'm also open to something completely different?
I was looking at this one for about $19 and does 0 to 100psi.

73  Forum 2005-2010 (read only) / Interfacing / Re: HVAC monitoring using opto-isolators? on: October 06, 2010, 04:01:13 pm
you could also use a single one wire temp sensor in the unit: temp drop cool on, temp raise = heat on - added benfit is that you know your unit's not only on but that it's working correctly...
74  Forum 2005-2010 (read only) / Interfacing / Re: Alternate water flow measuring on: October 01, 2010, 12:37:34 pm
I guess it depends on what pins you use:
75  Forum 2005-2010 (read only) / Interfacing / Re: Alternate water flow measuring on: October 01, 2010, 09:48:53 am
That's a good point on the focus at some distance you would get nothing - I wasn't thinking so much of needing to focus the mouse eye but reading dark vs not dark - or having a dark line in the picture. I'm not even sure that the arduino could process a characteristic (in this case a line) within the eye but you might be able to check bits to see if there all dark at fixed locations.  
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