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1  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 08, 2014, 07:31:58 pm
http://www.trustedreviews.com/news/Lexar-Memory-Key-Adds-Storage-Gauge

I do not know if the patent is so broad as to cover "visual" to include LCD and LED, etc.

Ray

Wow, pretty cool. That's the one they came out with in '06. This is they're latest and greatest : http://www.lexar.com/products/lexar-jumpdrive-m10-secure-usb3-flash-drive?category=207
2  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 08, 2014, 09:08:12 am
The obvious approach would be to put something between the flash storage and the external interface that passed I/O requests through and added the capacity monitoring/display logic. There would be quite a lot of work to do, because it'd need to understand the file system as well as the I/O protocol, and USB is complicated in its own right. I suspect that the simple approaches to achieve that would cripple the throughput, too.

I watched a presentation recently from a team that had reverse-engineered some SD storage cards and discovered that they contained programmable microcontrollers to do the storage management and error correction. Figuring out how to reprogram the controller without support from the manufacturer seemed like a really tough challenge, and I think there was still a lot of work to do to figure out the instruction set and architecture and so on, but they had got as far as uploading their own code and using it to control I/O pins to turn LEDs on and off. I think you'd need to solve all that in order to embed the logic into the storage device itself, and unless you're working with the manufacturer it would be extremely difficult. I expect the same would hold for other flash devices such as USB sticks. It's only a matter of time before somebody cracks all that, though, and then I don't see why it would be any more complicated than programming an Arduino.



The more I look into this the more daunting it seems. Sure would be nice to be able to interface with though.
3  Using Arduino / Project Guidance / Re: Safest way to switch 110V AC on/off on: January 06, 2014, 03:45:37 pm
Powertail is good, or you could also use something called a Solid State Relay. It's controlled off of a 5VDC potential with a small enough current draw to be able to be used directly off a microcontroller.
4  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 06, 2014, 01:56:58 pm
Look at what's in a USB drive
http://en.wikipedia.org/wiki/USB_flash_drive
There are several pics of the internals.

I was just checking that out, hah!
5  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 06, 2014, 01:30:50 pm
So you really need something like this
http://www.saelig.com/EL/ICSDSDIO001.htm
Provides the PC/USB connection to the memory device.
Add some circuitry to let a microcontroller control the chip as well so you run your own query on memory usage (# of files, size, do the math & light the LED).
Not for the faint of heart.

Definitely not for the faint of heart. But at least I have some direction so thank you for that!

Anyone else have experience or any other ideas/recommendations?
6  Using Arduino / Project Guidance / Re: Where to find a custom usb flash memory drive or have one made? on: January 06, 2014, 01:05:50 pm
So a flash drive with an Atmega 8U2 basically that you can send messages as to which color to light up. Otherwise, the controller has to monitor all traffic and recognize the file format, how big files are, when they are added/deleted, sounds like a nightmare to code.

I'd probably end up having to go the ways of kickstarter for this or finding a software engineer who's up for a challenge. Granted, I don't know code as well as a programmer but I guess to make it easier it could be designed/programmed to check memory upon bootup/connection, not necessarily during reading/writing.
7  Using Arduino / Project Guidance / Where to find a custom usb flash memory drive or have one made? on: January 06, 2014, 12:46:27 pm
Hey everyone,

I have a project in mind that involves a usb memory stick. In the end I would like a flash drive (exterior casing not needed) that with an RGB LED on the end of it.

Right now all I've done is soldered a resistor and LED onto the VCC and GND pins  (1 & 4) on the USB connector. This lights up the LED constantly as long as it's plugged in. I would like to control when and how it lights up.

Ultimately my goal is to program the flash drive so that the LED responds to the drive's memory capacity. For example blue or green when empty, yellow when it's halfway, and red or flashing red towards max capacity. Once that's done there's a case that I would like to build around it so that the LED's light radiates through it and makes the whole case glow.

Are there any companies out there that can or already build custom flash drives with programmable IC's? I would like to be able to program the on-board IC to control the LED's behavior without it affecting the flash memory. This way the end-user can't accidentally corrupt the firmware controlling the LED.

I hope that made sense. Thanks in advance!
8  Using Arduino / General Electronics / Re: How can I replace this relay with a MOSFET? on: November 12, 2013, 07:21:49 pm
Thanks again for the help.

I decided to redraw my schematic to account for a solid state relay. Now the light should only turn on when both the rocker switch is on and the reed switch is on (door open).

What I'm doing is mounting a light and using the relay to interrupt or source power to it while maintaining the rocker switch built into the housing. This will let me cut power to it preventing the light from turning on in case I need to leave the door open for a long period of time, like when I air out the house.
9  Using Arduino / General Electronics / Re: How can I replace this relay with a MOSFET? on: November 12, 2013, 03:53:23 pm
Good to know. Thank you so much!
10  Using Arduino / General Electronics / Re: How can I replace this relay with a MOSFET? on: November 12, 2013, 03:47:01 pm
I can't believe I completely forgot about solid state relays lol. Thanks jremington!

Why wouldn't I be able to use MOSFETs for something like this?
11  Using Arduino / General Electronics / How can I replace this relay with a MOSFET? on: November 12, 2013, 03:36:01 pm
I'm taking a CFL (flourescent light) and modding it to have it turn on automatically when a door is opened via a trigger from a magnetic reed switch. Ultimately I'm trying to add automatic lighting to a closet so a wall switch doesn't have to be installed or used.

Below is a quick sketch of the overall circuit. I plan to use a cell phone charger as my 5Vdc source to energize a 5V relay to interrupt a 110Vac source that powers my CFL. Quick searches online revealed that the 5Vdc relays I were finding were not capable of handling high current. The light doesn't draw more than 5A but I would like to play it safe and use components that can handle up to a 10A load anywhere the 'high' voltage lines are involved.

I'd like to use MOSFETs (if possible) to replace the relay. Relays are bulky and noisy, but also I'd like to experience using MOSFETS as a replacement for relays.

What would you guys and gals suggest?

12  Using Arduino / Project Guidance / Re: LED Strips with MOSFET Will This Work? on: April 18, 2013, 11:25:40 am
In short, yes. You can use a MOSFET to supply power to your LED strip.

If you could redraw your circuit a little neater it'd make it easier to make sure whether or not you have it set up correctly.
13  Using Arduino / General Electronics / Re: Transistor Gain/Saturation question on: February 14, 2013, 12:19:18 pm
Quote
The LED dimmer is a little harder for the Arduino because, while there is A2D pins, there are no D2A pins. 
Usually method for dimming LED is to use PWM signal to switch them on.quickly. Eye sees it as full on (persistence of vision) while average on-time is conrolled by PWM width.


Yup, I was just using that as an example. I'm intending to play around with BJTs to get a little more familiar with them (hands-on has always worked better for me than just reading) and eventually use them to "fade" or adjust current or voltage levels to something a little higher powered.

Up next, H-Bridges 101 smiley-grin
14  Using Arduino / General Electronics / Re: Transistor Gain/Saturation question on: February 14, 2013, 11:57:27 am
Absolutely, sorry about that! And most of all thank you!
15  Using Arduino / General Electronics / Re: Enable more power in usb port on: February 14, 2013, 11:56:47 am
"will it work" will depend on a lot more than just the supply. However, you mentioned you were looking for a 9 2A power supply (which I linked to). The one you linked to is a 9V 3A power supply. They will both work the same, with the difference being that the one you linked to can source more current.

Basically if you wanted to draw about 2A of current, using a 3A supply would be safer.
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