Show Posts
Pages: 1 ... 6 7 [8] 9 10 ... 25
106  Using Arduino / Microcontrollers / Re: How to enable BOD fuse? on: June 21, 2013, 01:19:00 pm
I just realized that I can just use Arduino as ISP to program Fuses smiley
Since I created Rapid BootLoader shield, it's pretty easy to do it with that...
In case someone finds this useful:
Code:
avrdude -C S:\programs\arduino\hardware\tools\avr\etc\avrdude.conf -P COM11 -b 19200 -c avrisp -p atmega644p -v -e -U efuse:w:0xfd:m
I verified it works great. Just replace path to avrdude.conf and COM number to your environment smiley
107  Using Arduino / General Electronics / Re: Battery life with step-up converter on: June 21, 2013, 10:01:43 am
Speaking of art of electronics I have cheap Atomic clock with wireless external temperature sensor. That sensor sits outside my window and runs of 2 AA.  Besides transmitting temperature it has built in small LCD display and LED. It's there in freezing winter temperatures or hot summer days, yet it works on same set of batteries for 2-3 years.  I don't know how the heck they managed to achieve such crazy efficiency (magic?), but I'm really tempted to take it apart smiley
108  Using Arduino / Project Guidance / Re: Laser interrupt sensor on: June 20, 2013, 03:55:37 pm
Quote
what happens when the led/diode stops working.
The in-built self-test detects it?
Ah yes, excellent idea!
I've used more than 1,000 led's , and even though they have 100,000 Hours , some have only lasted for 2 days. Which one will last the 100K Hours probably 5% or 95% or none.

The best led's were the original Gallium Arsenide, and thats what everyone sees in the 90's devices. Unknown that these new led/diode are safer for the (GREEN) environment. hmmmm!
Hmm interesting. Perhaps pulsing laser beam will extend diod's life...  I know they use them in the banks, museums, just don't know what kinds smiley
109  Using Arduino / Project Guidance / Re: Laser interrupt sensor on: June 20, 2013, 03:50:43 pm

I like the diode/led , but.. , what happens when the led/diode stops working.

What happens to the user?
Is this a serious question? smiley-grin
I guess depends on the person.  If it's a sane person, he'll contact me for repair exchange it, or just go on with his/her life smiley  We are not talking about life support system here, just an alarm clock smiley
BTW I currently make these clocks, and it just happened that because of the large display, easy to press buttons and vocal announcements of time/date/temperature/alarm settings I was approached by a physically disabled person, so I had few ides on how to modify them to make even more convenient for such people.
110  Using Arduino / General Electronics / Re: Battery life with step-up converter on: June 20, 2013, 03:31:20 pm
No it needs to be 3.3V
111  Using Arduino / Project Guidance / Re: Laser interrupt sensor on: June 20, 2013, 03:28:12 pm
I don't know of many blind people that will see the led, but the touch sensor can be the whole enclosure, there are conductive paints / foils & inks, you're expecting someone who is blind to be in the correct position in order to trigger the led, whereas the touch sensor can be accessed in any direction.
Of course I don't expect blind person to see LED. But I with my eyes closed can find where my alarm clock is located, and getting hand close enough will interrupt beam and clock will announce time, and other information. Plus clock will have large arcade buttons and special cutouts (guides) in the acrylic to locate them. Of course conductive sensor are also good idea, I just want to try several ideas. Thus my question about long lasting laser LEDs...
So I take it nobody knows if such diodes exist?
112  Using Arduino / General Electronics / Re: Battery life with step-up converter on: June 20, 2013, 03:18:16 pm
Or a C or D, lot more capacity there.
No that's too big. Sensor needs to be pretty small so I can fit between window and bug screen smiley
Worst case, 9V battery, but then I have to find very efficient voltage regulator...
Fig 57
Ah, there it is! Thanks! smiley
113  Using Arduino / Project Guidance / Re: Laser interrupt sensor on: June 20, 2013, 03:13:02 pm
You probably need neither laser nor collimation.
smiley-eek
114  Using Arduino / Project Guidance / Re: Laser interrupt sensor on: June 20, 2013, 03:09:16 pm
Why not a touch sensor, which will last waaay longer than the led?
I'm not sure how to embed it in the acrylic enclosure. It'll have to cover some area...
What sort of separation do you need?
Between emitter and sensor?  About 6 inches
115  Using Arduino / Project Guidance / Re: Laser interrupt sensor on: June 20, 2013, 02:57:59 pm
Why does it have to be a laser?
A collimated LED may be more sensible.
Doesn't have to be a laser, but it needs to be small and cheap smiley  I'm no familiar with collimated LED, is it some kind of LED with focusing lens?
116  Using Arduino / Project Guidance / Laser interrupt sensor on: June 20, 2013, 02:53:09 pm
I want to make talking clock for people who can't see. I'm thinking about using laser diode and photo-resistor so when person's hand interrupts beam it will trigger clock to announce time.  Right now I'm having difficult time finding a low power laser diode that's rated to for long constant operation. Are there such diodes that can work for years nonstop?
117  Using Arduino / General Electronics / Re: Battery life with step-up converter on: June 20, 2013, 02:01:33 pm
You also have to figure that powerout = powerin minus some loss.
Spec on the part is

"High Efficiency 85% (Vin = 2.0 V, VOUT = 3.0 V, 70 mA)"

So powerout = 2000mAH * 0.85 = 1700mA roughly.
What's your current draw going to be like?
Thanks!  Draw should be pretty low but I haven't calculated it yet. I'm powering Moteino w/ RFM12B transmitter and DS18B20 temp sensor.  Without putting chip to sleep and sending readings every 30 seconds I my AA lasted  just a little under 1 week.  So I wanted to figure out if step-up converter might be burning much of the juice. My goal is for battery to last at least a year. I plan to try using Watchdog timer and only transmit readings once every 5 minutes. Also I might use 2 AA...
118  Using Arduino / General Electronics / Re: Battery life with step-up converter on: June 20, 2013, 01:45:19 pm
Datasheet gives operating current for each variant, the 3V3 one is 45uA, typical.
2000mAh / 45uA = 5 years.  Your battery will self-discharge much faster than that.
Excellent! Thank you very much! Out of curious where did you find 45uA number?  I don't see it in the Datasheet...
119  Using Arduino / General Electronics / Battery life with step-up converter on: June 20, 2013, 01:33:48 pm
I would like some help figuring out how long a typical single AA battery (2000mAh) will last connected to a 3.3V step up converter without any load.  This is the converter I'm using.  There's datasheet but I'm not entirely sure how to get information that I need to determine battery life.
120  Using Arduino / Programming Questions / Re: Arduino WebServer input on: May 29, 2013, 06:28:26 pm
Some simple web page control code.

Neat! Thanks for sharing!
I also got mine working. It drives Roomba across the room smiley  Although bumper sensors are not working for some strange reason (I enabled Safe mode which suppose to override any movement if Roomba encounters obstacle).  Am attaching the code (very rough, but it works!) in case anyone is interested. It uses Serial1 ports of Arduino Mega, so if you have Uno you'll need to adjust it (use SoftwareSerial instead).
Pages: 1 ... 6 7 [8] 9 10 ... 25