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1  Using Arduino / General Electronics / Re: Regulating DC Voltage on: April 22, 2014, 07:30:44 am
Well I picked up a DC buck boost regulator from eBay, just waiting on it to come in the mail.
2  Using Arduino / General Electronics / Re: Regulating DC Voltage on: April 21, 2014, 08:07:02 am
The dimensions would be  18650, ~18mm (w) x 650mm (h).

650mm long ? Are you sure ?
That can't be right. that's 25 inches , more than 2 feet long.
  A meter is 1000mm

Woops! I just skipped right over the decimal, lol! 65.0mm... Sorry! Hahaha!
3  Using Arduino / General Electronics / Re: Regulating DC Voltage on: April 20, 2014, 10:22:02 pm
I'm sorry, when you say dimensions you're talking about the physical size of the battery, correct? The dimensions would be  18650, ~18mm (w) x 650mm (h).
4  Using Arduino / General Electronics / Re: Regulating DC Voltage on: April 20, 2014, 10:13:22 pm
http://originvape.com/product/efest-flat-top-high-drain-35a-18650-2500mah-battery/

You need to be more specific about your battery specs.
There are two ratings regarding current
1 mAh rating (mAmps continuous for one hour)
2 Discharge rate (called "C" rating for Lipo batteries) is usually specified with two numbers;
         A. Continuous discharge rate (self explanatory)
         B. Max burst discharge rate (discharge rate for 10 second burst)

The same voltage battery may be available in many different mAh ratings and discharge rates
2500mAh/35A = 14C (14 times the discharge rate of the mAh rating , in this case 14 times 2.5A/per hour)
Stating that your battery is rated for 35A in no way means in could not have the shape or size of the one shown in the link I posted since the battery shown in this link is the same size but as you can see if read the description , is rated for 35A

The link you posted is in fact the batteries I have.
5  Using Arduino / General Electronics / Re: Regulating DC Voltage on: April 20, 2014, 07:48:18 pm
Thank you for the info, I'll give the boost regulator a shot! Hopefully that will workout. As for the battery I'm using one rated for 35A so I don't think it's going to lack in that perspective.
6  Using Arduino / General Electronics / Regulating DC Voltage on: April 19, 2014, 11:14:52 pm
I have constructed a circuit that has an Arduino Pro Mini (3.3v) along with an LCD screen (3v) that is being powered off of a single 18650 battery ( 4.2v – 3.6v). The purpose of the Arduino is to take a analog reading of the voltage of the battery while the 18650 is also powering a higher ampere secondary circuit. The problem I’m running into is when I’m running the secondary circuit, the backlight and the contrast in dimming on the LCD readout due to a drop of voltage (brings it to 2.5v) along with effecting the Arduino as well seeing that I’m running the 18650 to RAW and the VCC is out to the LCD.

Now, is there anything I can use to eliminate that voltage drop while the secondary circuit is in use? I'm not able to use a voltage regulator due to the minimal amount of provided voltage so a LM317 is out of the question... If you have any ideas, I would love to hear what you have to offer. Thank you in advanced for your help!
7  Using Arduino / Displays / Re: Help w/ Display (Drivers SPLC780D OR ST7066U) on: April 14, 2014, 11:12:03 pm
You aren't providing much information.  Are you sure that the current drain of the backlight isn't causing your supply voltage to sag?

Don

I thought about this a little more, I have a regulator circuit on this to step down to 3v... Now, it's working perfect! Well other than I had to change the resistor on the contrast. When I have the LCD on the text disappears and when I have it off it works fine. I have to find the right resistance that will work for both. Not really a big deal. Thanks for the help Floresta!
8  Using Arduino / Displays / Re: Help w/ Display (Drivers SPLC780D OR ST7066U) on: April 14, 2014, 10:37:33 pm
Yes, Voltage is good. The display is working fine, it's just displaying random nonsense. What information could I provide you that would help with diagnosing the issue? I really do appreciate your help on this!
9  Using Arduino / Displays / Re: Help w/ Display (Drivers SPLC780D OR ST7066U) on: April 14, 2014, 09:39:38 pm
According to the data sheet that you linked to this is a 3.3v device.  Have you taken that into account?

Don

Yes sir.
10  Using Arduino / Displays / Help w/ Display (Drivers SPLC780D OR ST7066U) on: April 14, 2014, 07:24:40 pm
I have just recently purchased some displays from New Haven Display and the drivers listed are SPLC780D OR ST7066U, from doing some reading prior to purchase, I saw that it is compatible to the Arduino because it's the same coding for the HD44780 driver (if I worded that incorrectly I apologize). I had a sketch running already that had a HD44780 screen on it and wanted to change the screen out to this new 4x20 display I purchased (NHD-0420AZ-FL-GBW-3V3). When I hooked it up, to no surprise it was NOT working properly. I tinkered around a little, did some reading (which has confused me more) and here I am!

To make this easier, I'm working off of the "Hello World" sketch which has the pin out as follows:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 5
 * LCD D5 pin to digital pin 4
 * LCD D6 pin to digital pin 3
 * LCD D7 pin to digital pin 2
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)

The display is on, and working it just has symbols and blacked out segments...

Here is the datasheet from the LCD display:
http://www.newhavendisplay.com/specs/NHD-0420AZ-FL-GBW-3V3.pdf

Any help would be much appreciated!  If I can supply any additional information please let me know what you need. Thank you in advanced for your help!

Pete
11  Using Arduino / Displays / Re: Arduino Mini Pro 3.3v LCD? on: April 10, 2014, 10:26:43 pm
I found one on sale at NewHavenDisplay.com
http://www.newhavendisplay.com/nhd0420azflgbw3v3-p-2003.html

The only thing that made me second guess, was the Controller/Driver: SPLC780D OR ST7066U, I wasn't positive that it would be compatible. From what I have read this would not be an issue, so I picked up 2 of them. I was a fan of this model because it only needs 2.7v min with typical being 3v and max at 3.3v and low mA so it won't kill the battery life either. It's perfect for my application. I really hope I don't have any issues with the drivers though... Staying positive and keeping my fingers crossed.

12  Using Arduino / Displays / Re: Arduino Mini Pro 3.3v LCD? on: April 10, 2014, 10:16:20 am
Sounds good, I'll take a look. As for the 4.18v max, that would be the max output voltage of a 18650 battery I'm using for the project. At full charge they ring in at 4.18v. Thanks again for the help!
13  Using Arduino / Displays / Arduino Mini Pro 3.3v LCD? on: April 10, 2014, 08:34:11 am
I'm looking into some lower voltage options from the 5v Arduino Uno. I was looking at the Arduino Pro Mini @ 3.3v however, I was wondering if anyone knows anything in regards to a compatible LCD screen it doesn't have to be 16x2, I'm really just looking for an LCD that would be able to run from 3.3v minimum, and maybe like 4.18 max. If anyone has any ideas please let me know, Thank you!
14  Using Arduino / Displays / Re: DV-20208 on: March 26, 2014, 09:28:50 am
Floresta, you're correct, I was leaving pin 3 open. I jumped it to pin 1 and I'm now displaying. Thank you very much for the help my friend! I hope you're enjoying the WNY weather as much as I! LOL!!!
15  Using Arduino / Displays / Re: DV-20208 on: March 23, 2014, 06:39:26 pm
Thank you for the help, I have to wait until my son goes to sleep for me to work on it. This is the LCD I purchased (please see the attached link).

http://www.ebay.com/itm/Data-Vision-DV-20208-HD44780-compatible-20x2-5x7-dot-matrix-character-LCD-/351022284470
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