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1  Community / Bar Sport / Re: Join the resistance! (humor) on: October 02, 2012, 04:03:19 pm
Could be a group induction ceremony ...
Good one!  smiley-grin
2  Community / Bar Sport / Re: Join the resistance! (humor) on: October 02, 2012, 01:52:51 pm
Very good,  but  do I sense some underlying reluctance amongst the monks ?
why would they resistsmiley-wink
3  Community / Bar Sport / Join the resistance! (humor) on: October 02, 2012, 01:00:33 pm
4  Using Arduino / Sensors / Re: [UPDATED] motion detector that works behind clear glass window? on: September 27, 2012, 11:15:19 am
Thanks John. I reversed the event ... when the beam of light hits the photocell the LED lights. Now I can determine from across the room when the beam is lined up. Break the beam, LED goes off. If I put this project into actual use, I will put a timer on the LED to go out after a few minutes of making alignment.

It's still difficult and tedious to make that alignment. I suppose that's just the way it is going to be.
5  Using Arduino / Sensors / Re: motion detector that works behind clear glass window? on: September 27, 2012, 10:43:59 am
UPDATE: I received the parts I needed and finally had the time to setup and test in my shop.

I'm directing this laser beam across the room into a mirror where it reflects back into this photocell. I placed a large diameter piece of heat shrink, about 1" long, around the photocell like a sleeve to cut down ambient light. At this time there is no glass window between the beam and mirror. When the beam is interrupted an LED illuminates.

The reaction time of the photocell is plenty fast enough. The main loop() in my code is running without any delay. I can swing my hand through the beam in a karate chop motion and reaction is fast enough to trip and light the LED. I can flick my finger (like you were flicking a piece of sand off a  table) through the beam and it triggers the event.

I do have one concern so far though. Trying to line up that dot of laser beam in the mirror and direct it back to the photocell is tedious. The slightest touch or bump of either mirror or Arduino and the beam is no longer hitting the photocell.  Any ideas on how to make that part easier?

I also am going to need some sort of a small mirror on a swivel joint. The mirror I have now is about 2"x3" and no swivel. Something like a motorcycle rear-view mirror would work, but that would be way too big and noticeable  on my porch. Any ideas?

Thanks,
Jake
6  Using Arduino / Sensors / Re: motion detector that works behind clear glass window? on: September 20, 2012, 07:12:24 pm
Thanks everyone for the excellent suggestions. I like the laser - mirror - photocell idea. Sparkfun has some lasers like this one and I could reflect the beam into photocell attached to an Arduino.

That would be a fun project to put together and learn from. If I do it I'll let you know how it goes.
7  Using Arduino / Sensors / [UPDATED] motion detector that works behind clear glass window? on: September 20, 2012, 05:03:34 pm
I did some searching but found only posts in the old read-only forum. I thought there may be more current information and/or products, so posting the question here.

I'd like to connect a motion detector to an Arduino and have it point at my porch from behind a clear glass window. Someone approaches my door and the Arduino is triggered.

Can someone recommend a motion detector that works from behind glass, or recommend what I should be searching for?

Thanks,
Jake
8  Community / Exhibition / Gallery / Re: Warning! One Million Ohms on: September 14, 2012, 07:03:36 pm
UnaClocker,

Great pic! That smile is worth a thousand words  smiley-grin  Congrats to your son for soldering the kit together. It would indeed make a good project for youngsters to gain more soldering experience.

Jake
9  Community / Exhibition / Gallery / Re: Warning! One Million Ohms on: September 07, 2012, 06:35:52 am
Here's mine, thanks Jack!  These boards are a lot of fun. I took mine to work and everyone there got a big kick out of it.

Regarding the kit: It's very easy to assemble. It took me about 10 minutes. The PCB is very sturdy and the silkscreen printing is clear and sharp. The hardware is excellent. I didn't expect a battery holder or power terminal blocks, but they were included. Everything you need is right there in the kit. The instructions are more than adequate with photos and wiring diagram on the downloadable PDF. You can add the headers for ICSP programmer if you want to tinker with the code, or re-program it all together. Jack has put the code up on GitHub for anyone who wants it. Nicely done Jack!

The use of button input and sleeping the ATtiny85 are nicely implemented in the code and I learned from reading through it. But there are already several different blink patterns with different timing, so I haven't felt the need to tinker with it yet. It's really cool as is!

I've ordered more of these as gifts for friends. I have several friends that are near impossible to find holiday gifts for. A couple of them are into electronics too. So these make a unique and affordable gift that is certain to entertain.

Lastly, Jack is a pleasure to deal with. Many of you already know of him from his posts in the forums here. I have asked Jack a couple of follow-up questions regarding things I didn't understand (in the microcontroller forum) and he went out of his way to help me. Thank you Jack!



Here is a short video I made with my iPhone that shows some of the blinking patterns. You simply press the button to change the pattern, which I do several times in the clip. Press and hold the button to power off, or it goes to sleep after 5 minutes:

YouTube: http://youtu.be/GAgEru5UjlU

Vimeo: https://vimeo.com/49014569
10  Using Arduino / Project Guidance / Re: GMT XML? on: September 05, 2012, 07:29:03 am
The public Network Time Protocol servers return UTC. It's up to the local system receiving the information to display it in any other timezone/format.
11  Using Arduino / Programming Questions / Re: [SOLVED] need help with second counting algorithm on: September 04, 2012, 11:44:01 am
I've got it figured out. I'm justing recording the millis() at the time of the event, adding 30000 and comparing that to the current millis() so I know when to stop showing seconds.
12  Using Arduino / Programming Questions / Re: need help with second counting algorithm on: September 04, 2012, 10:41:03 am
My clock normally displays HH:MM all of the time. I wanted to be able and have an event that would completely clear the display and show the seconds tick off for some pre-determined duration (currently 30 seconds).

I may be able come up with some simpler code by using/referencing millis(), i.e. working it into the pseudo code above in place of current hour, current minute, current second.
13  Using Arduino / Programming Questions / Re: need help with second counting algorithm on: September 04, 2012, 10:31:39 am
This is some pseudo code. This should work I think:

Code:
if(event triggered) {
  showUntil = current hour, current minute, current second + 30;
}

if( showUntil >= (current hour, current minute, current second) ) {
displaySeconds();
}

If I can get the seconds elapsed since the epoch from the DS1307, the above should be easy enough to code.
14  Using Arduino / Programming Questions / Re: need help with second counting algorithm on: September 04, 2012, 09:56:03 am
As I wrote in my original post, "The following code won't work, but it could serve as a starting point:"

I don't have any additional code to show. My objective to to stop calling the showSeconds() function after it has displayed digits for 30 seconds.
15  Using Arduino / Programming Questions / [SOLVED] need help with second counting algorithm on: September 04, 2012, 09:44:01 am
I'm wanting to display seconds on a 4x7 segment display that normally shows HH:MM. I only want to display the seconds for 30 seconds. There is no delay in the loop and I don't want one because the ATmega328P needs to be zooming along doing other things.

So from the main loop() I wanted to call this function showSeconds() (many, many times since there is no delay) until 30 seconds have been displayed, then stop calling the function. I'll trigger the call to showSeconds() with an external event, that part I have no problem with.

But the algorithm to show then stop showing the seconds is evading me.  I'm willing to use global variables or whatever is required.

I cannot simply increment/decrement a counter, because the showSeconds() function will be called many times per second. Maybe I could use some global counters?

The following code won't work, but it could serve as a starting point:

Code:
void showSeconds()
{
  int currentSecond=0;
  int duration=0;

  getDateDs1307();  // gets the current time, populates global 'second' with current second, 0 to 59

  currentSecond = second;
  duration = currentSecond - 30;  // want to display seconds for 30 seconds
  
  while(duration++ <= currentSecond) {
     displaySeconds(); // an external function that shows current seconds on the display
  }

}


Thanks for any help.

Jake
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