Show Posts
Pages: [1] 2 3 4
1  Using Arduino / General Electronics / GPS Battery Life - Upgrading to bigger Lithium-Ion Battery on: September 20, 2013, 09:51:25 pm
I have a GTU 10 from Garmin.

I want to extend it's battery life by replacing and soldering on a new battery and enclosing the battery and the GTU 10 in a Otterbox 2000.

I would like to be able to charge the new battery through the USB connector on the circuit board, so is it possible to do? What should be the specs on the new battery? Why does the battery have 3 contacts?

After removing the shell, you are left with a 3.7v, 740 mAh, 2.7Wh Lithium-Ion
battery and the circuit board.

Bottom w/ Battery:

Top (GPS Side):
2  Using Arduino / Motors, Mechanics, and Power / Can I run a 40A ESC off a switching mode power supply instead of using a LiPo? on: September 01, 2013, 07:43:53 pm
I have a 40-Amp Pro Switch-Mode BEC Brushless ESC can I run this at 11.1V off a switching mode power supply like mine below?

3  Using Arduino / Microcontrollers / What's the difference between the Arduino ADK and the Mega? on: August 31, 2013, 03:39:31 pm
They have an Arduino ADK on clearance at radioshack for $19.99, and I just what to know what's the major differences can it still do everything the Mega can do? I don't want to use it for android just electronic projects.
4  Using Arduino / General Electronics / Need a Banana to Arduino power supply adapter - will this work? on: August 26, 2013, 10:16:51 pm
I just got the power supply below. I'm looking for a power supply adapter for Arduino.

Will the one from HobbyKing below work? My concern is about the jack not the banana side.

http://www.hobbyking.com/hobbyking/store/__17061__JR_and_Futaba_TX_Charging_lead.html

These are the specs from Here.
Code:
Plug 1)
Outside diameter: 5.49mm
Inside diameter: 2.52mm
 
Plug 2)
Outside diameter: 5.49mm
Inside diameter: 2.12mm


5  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 22, 2013, 10:11:41 pm
Thanks CrossRoads!

Do I need anything else like pull up resistors for the FET?

Which of these is the best to use?

http://www.digikey.com/product-detail/en/NDP6020P/NDP6020P-ND/1055922
http://www.digikey.com/product-detail/en/NTD5867NL-1G/NTD5867NL-1GOS-ND/2401422
http://www.rapidonline.com/pdf/47-0552.pdf

I'll be posting a finished schematic and pictures when I'm done.
6  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 22, 2013, 04:00:53 pm
You need a resistor from V+ to the anode.
You need a 2nd '595 and ULN' connected to the anode.
Replace the ULN on the cathode with a heftier transistor that can sink current for the whole layer.

When the Anode is NOT pulled low and the cathode layer is pulled low the LED will turn on.
When the Anode IS pulled low and the cathode layer is pulled low the LED will NOT turn on.


Based off your info above I made the schematic below. Is this schematic correct? What should I use for the FET?
7  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 22, 2013, 09:40:28 am
See if this helps.
In this case I shifted 1's into the TPIC6B595 to sink current from the anodes so they didn't turn on when the cathode was low.
When 0 was shifted in, the current flowed into the LED anodes. Those are the 64 anode columns.

I used ULN2803 to sink current from columns, in your case use a bigger transistor to sink current from a whole layer.

I still don't understand how that works. What do I need to modify in this schematic?
8  Using Arduino / General Electronics / Workbench Necessities on: August 21, 2013, 11:54:56 pm
I have recently renewed my interest in electronics. Now that I am older and can afford to build a proper workbench for my future projects I want to get some recommendations on what I should purchase. Please tell me what you recommend and the brand/model/type you would get.

I just bought a Extech PSU today smiley

EXTECH-382275-Switching-Mode-Power-Supply-600W-DC

http://www.extech.com/instruments/resources/datasheets/382275_76data.pdf


Thanks
9  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 21, 2013, 08:21:43 pm
Can use HC595 to source current to anodes, just limit it to 8mA.
(Vs - Vf - Vc)/.008 = resistor value
Vs = 4.8V from HC595 - IOH drops with higher current - 0.2V loss at 6mA, could be as high as 0.52V (assuming similar drops with Vcc at 5V vs 4.5V in datasheet).
Vf = drop across LEDs (varies by color, blue typically ~3.7V)
Vc = drop across cathode sink device:
N-channel MOSFET will be lowest, NPN will be higher, ULN2803 even higher, like 1.3-1.6V.
ULN2803 only good for 500mA/IO, will be on the edge with 8mA/column, may need to use 2 IOpins/layer. Blue may not even turn on if Vf is 3.7V.
3.7V + 1.3V = 5V, greater than 4.8 that will be available.

Better off with MOSFET, with low Rds of 0.025ohm will have just 12.5mV drop & hardly any power dissipation:
P=I*2 * R = 1.28*1.28*.025 = 41mW.

ULN2803 only sinks current.
You could use them as anode "anti-drives" (just made that up):
+5 to current limit resistor to the anode.
When UNL2803 output is off, current flows into LED.
When ULN2803 output is on, current flows thru the ULN2803 instead, and LED stays off.
Then on the cathode, 4 ULN2803 IO pins/layer can sink the1.28A coming down the columns. Will be quite warm, maybe use a while chip per layer. I'd wire up just 1 layer to start, do some testing.
Still the question if there's enough voltage left for the LEDs to turn on.




I want to use nine 74HC595s, with 8 using your idea of the "anti-drives" for the anodes, and the last register using transistors or MOSFETs. I think I should use transistors or MOSFETs for the layers (cathodes) since the current is higher than the UNL2803 can handle.

What do suggest I use for the layers? Can you also explain your "anti-drive" setup in more detail? I know the outputs from the 74HC595 go the the UNL2803 then after that I am confused.
10  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 21, 2013, 05:51:36 pm
How about....

64 x bc327

8 x ?

Paul, You mentioned using the ULN2803 to sink current for the cathodes.

Since I want to use 9 shift registers, 74HC595, could I pair them each to a ULN2803? Eight to the anodes and the last pair for the cathodes?
Can I source and sink current through the ULN2803?
11  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 21, 2013, 03:47:31 pm
What if I still wanted to use the 74HC595? Do I need 72 transistors? What type?
12  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 21, 2013, 12:26:44 pm
There's this one.
CD74AC164.
Need N-channel MOSFETs or NPN transistors to sink 1.28A of current from the layers.


So I could daisy-chain 9 of those with the last controlling transistors/MOSFETs of some type to turn the layers on and off?

Question #1: How do I connect those ICs to the Arduino and to each other.
Question #2: Can I still use the shiftOut function?
Question #3: What is a suitable transistor/MOSFET?  
13  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 21, 2013, 12:10:27 pm
I really don't want to change the physical design of the cube layers (cathode) columns (anode).

Why not? Did you already solder up the cube?

Yes, it is near completion. I chose to build it this way to simplify the build process and provide the maximum distance between the LEDs. Since the anode lead is always the longest it easily overlaps the LED in the previous layer as shown below in the first image on the corner of the cube. By constructing the cube this way there is no need to modify the lengths of the LED leads before building.

14  Using Arduino / LEDs and Multiplexing / Re: Led Cube on: August 21, 2013, 11:50:37 am
I really don't want to change the physical design of the cube; layers (cathode) columns (anode). I want to make this with as few parts as possible.

Question: Is there an IC similar to the 74HC595 with 8 outputs that can source 20mA?

Thanks
15  Using Arduino / LEDs and Multiplexing / Led Cube on: August 21, 2013, 11:26:18 am
I want to build an 8x8x8 LED cube.

These are the main materials I currently have:
  • Arduino UNO
  • 3mm Diffused Blue LEDs (x512)
  • SN74HC595N (x9)

I want the first 8 shift registers to control the 64 columns (anode) and the last shift register to control the 8 layers (cathode).

Question: If each LED is drawing 20mA and I turn on a whole layer thats 1.28A, is this feasible with the SN74HC595N?
Pages: [1] 2 3 4