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1  Using Arduino / Project Guidance / Re: Bluetooth based watch and socket on: July 27, 2014, 09:09:18 pm
no.. I dont think so....(re:RFID)

from what I know from playing around with my MiFaire RFID set-up is that the range is extremely limited.  were talking 'near' contact only...  so they would have to lift something up off it/away from it and the relay would trip..  There may be other set-up they have a it more range, but not sure how large really and at what prices.  (do you need something mobile?)

what 'IS' the limit you are looking at?  you're not really telling any real specs you are looking to build for/toward. smiley

I would google all these topics yourself to make sure I am even correct... I am an noobie myself, and these comments are just from my limited reading and mostly knowledge/results from playing around with these components (ordered through ebay).. lol..

I'm a sure someone before you has wanted to know the distance using bluetooth.. (maybe with another component as well?)  see how they approached and solved it.

2  Using Arduino / Project Guidance / Re: RFID as Storage on: July 26, 2014, 10:59:50 pm

as mentioned..  I dont think the RFID cards/badges/key-fobs will have enough storage/space to store anything like audio.

You can store certain types of data in pre-determined areas on the card (chip)..

IMHO...  you could use an Adafruit WaveShield (or similar)

and save multiple .wav files on the SD card and access/play back any one of them based on the card that has been 'scanned'.

you can even set certain variables on a .txt file and load them in your sketch to even extend your project further without having to pljg in your computer and upload a new sketch.  the SD gives you storage for many .wav files..  and also the storage to put in a config type file to change/update small aspect of your code/program, again all without needing the Arduino IDE..  any old SD/microSD card reader gives you access to change the config file..or upload/save more .wav files (or change them out)..etc

3  Using Arduino / General Electronics / Re: Best way to power 3w RGB LED? on: July 26, 2014, 10:48:44 pm

thanks for the reply/clarification..

* oh they 'are' leds.?..  (I wasnt sure as there were 2 and how it applied to my set-up/question)..

* I believe I have only seen something like I/O (input/output) before... so I wasnt clear what it meant.

question: in the schematic posted, wouldnt BOTH leds be pwm'd at the same time since there is only 1 Arduino pin in use here?

if my goal is to have each die on the RGB led star then I need to have one of these circuit designs/layouts for 'each' channel (thats what you're saying 'yes' to...correct?)..  that means only one 'led' per 'circuit'...

using the schematic design above as an example...  this wouldnt work (as it is) being as there is two leds on one (constant current) 'circuit' and I want to individually PWM control each color.

(sorry if some of these seem stupid or obvious..but when/while still learning., when I see slightly different things, I'm not always sure if its how I'm supposed to do things...just an 'example' but not directly transferable to my project/question..etc. so I ask to can learn from solid building blocks/facts in baby steps)

Is that a 4.7k resistor?  (or 4.7M?..thats a pretty big resistor

Hopefully I can whip up a variant to my LM317 constant current approach/pcb this weekend and send out for some pcb's


Thanks for the alternate approach suggestion.. so then all (6 per group) pins would would be connected together and go to one die/color/channel?

Something to keep in mind...  but I think trying to learn how to make a proper constant current driver circuit will just help me in furture projects to come as well....  smiley
4  Using Arduino / Project Guidance / Re: Bluetooth based watch and socket on: July 25, 2014, 07:44:37 pm
I'm not sure about getting any sort of distance from a bt module.. (I suppose it would depend on the specific module?)

I have only played with the HC-05 type modules.. (which I thick are roughly 30 feet or so limit?)

anyways..  can you do a query/response type of approach? and if you dont get a 'response'..  you can assume you are out of range? and then trigger relay?
5  Using Arduino / General Electronics / Re: Digital Ground/Analog Ground, Arduino Gets Stuck! on: July 25, 2014, 05:13:40 pm
are your GND's connected?

I have seen some odd behavior powering servos from batteries.. where the GND's were not connected to the Arduino as well..

Also what does 'stuck' mean?  Like it doesnt boot?  it does some odd behavior?  get to certain point then wont respond any more?
6  Using Arduino / General Electronics / Re: Best way to power 3w RGB LED? on: July 25, 2014, 05:04:58 pm
Sorry for the late reply here..

(didnt get an email notification)..

I'm planning to give it another go this weekend (finally).. so I'll have to try and search around and see if I can understand your schematic (which I appreciate) that you posted.

So would I be using/making one of these 'circuits' (as you posted) for each die/channel on the led?...  right?

The 'O/I' is the Arduino pin...correct?

What are the components under the Vcc+

7  Using Arduino / Project Guidance / Re: 4 Digit, 7 Segment Counter Help on: July 20, 2014, 08:31:48 pm
I to would suggest that same chips CrossRoads suggest (MAX72xx chips)

Where my advice differs is that being that you are new, you may want to look into using one the available libraries to get your project up and running..

I use the LedControl library alot myself for quick and easy set-up

That being said the advice & approach given above will make you a better coder and understand the SPI protocol so it can be applied to other projects/SPI devices..    It is a 'crutch-free' approach and ultimately gives you more control instead of being pigeon holed into only being able to use the pre-made functions of a library.

8  Using Arduino / Project Guidance / Re: Controlling Arduino using iPhone on: July 20, 2014, 07:51:00 pm
Thanks!  I did -not- know about this limitation with iPhones!!

(how sad).. I really like the HC-05 BT modules!  they are only a couple dollars (USD).. and are dead simple to use!

Its a shame those iDevice people cant take advantage of this!
9  Using Arduino / Project Guidance / Re: wifi rgb light remote on: July 20, 2014, 03:02:48 am
umm...good luck?  smiley lol..

seriously.. was there a question in there?

if you dont want to use your iPhones 'data' (not sure what you mean though?)..then I suggest a bluetooth module.

they are dead easy to work with.  You could also develop/write an app for your phone that uses its bluetooth to control the app a bit easier then just a regular bluetooth terminal type well as another arduino device if you want a dedicated 'remote'

Are you planning on using high powered RGB leds? (like an led star?), if so you need to focus on making/implementing a constant current driver for this as well.

10  Using Arduino / General Electronics / Re: Best way to power 3w RGB LED? on: July 17, 2014, 12:02:04 am
that is correct..  as stated this is NOT the current circuit/design...  this is an example of the only type of constant current driver I have done before....  (and also as mentioned it was only designed to use 1 channel/color at a time)..

however I was told that using the LM317 it not the best approach.  if that is not true, and this is fine... then I'll just add 2 more and make so I -can- color mix....  but if it is NOT the best way..  then  I was/am asking what other IC can be used?  or some links to a nice and easy to follow set-up of a constant current driver.  The one posted doesnt seem a as easy or straight forward as using an LM317 though... (uses more components...etc)..

a quick google search shows that many people use this LM317 set-up in a similar fashion though?? 

so to summarize, yes you are correct..  that particular board design & schematic were designed to only have 1 channel on at a time. smiley

11  Using Arduino / General Electronics / Re: Best way to power 3w RGB LED? on: July 16, 2014, 08:53:34 pm
Thanks for the reply guys.


haha..  I'm trying to get 'comfortable' with learning how to make a 'correct' constant current driver.  Why I am askingfor advice/suggestion on an easy to use chip for this purpose. smiley  Something that doesnt have alot of extras/fluff to side-track a beginner like myself to all this..

I have made this pcb in the past (as mentioned) using an LM317 chip:

but if I recall this was an old chip and an old approach (although it worked and what was in the datasheet)

I would just do this 3 times (1 for each channel/die of the led) if not for the recommendation there was a better way. (so I am trying to ask/learn) smiley


sorry, I guess I was thinking (erroneously) that I needed to have a power supply with enough voltage for  all three led channels to be on...

So if I used a 5v wal-wart as my 'source'.....  would that mean running my Arduino without a vRegulator? (since I usually use some sort of vReg to keep a constant 5v feed to my Arduino circuit...  and then a +3.3v regulator fed -from- the +5v power any other this case the BT module)

so just a 'raw' +5v power source (direct from wal-wart for example).. and then all my circuits in parallel from that?


Thanks for the schematic.  I only briefly looked at it.... (and am already
which I'm sure stems from my lack of experience in this area.. smiley

but it uses BOTH a transistor and a moseft?..   

excuse my ignorance on this question, normally how a constant current driver is set-up? (and not through some dedicated IC or something?)

I have not read the link yet.. but will do so in hope I keep learning.  Appreciate it.

@GrumpyMike (again) lol..

Your comment makes me feel like this is not the best way?  I'm also not clear what you mean by 'power' resistor?  Are you referring to resistors that rated for like 1w and over? (would like to know so when I see the term again in use I understand the meaning)

Also (on a side note) what ever happened to that board I shipped out to ya in the UK?  smiley

Thanks everyone.

12  Using Arduino / General Electronics / Best way to power 3w RGB LED? on: July 16, 2014, 12:55:30 am
I'm not asking for any schematic/diagram here...just some general discussion/feedback (suggestions)

I'll make/post my Eagle files for 'review' once done...

I want to whip up a custom pcb that is basically a stripped don 'Arduino' with an on-board RGB led (to stick in some lamp project), and an HC-05 bluetooth module embedded.

anyways..  I started to think that using a high powered RGB LED (star)  might be  better way to go (for maximum brightness)..

the specs for the led are as follows:

    Red: 2.5V ~ 3.0V, 350mA
    Green: 3.2V ~ 3.8V, 350mA
    Blue: 3.2V ~ 3.8V, 350mA

- Star size: 20 x 20 x 1.6mm

- Note: each color channel is able to take a maximum of 350mA of current, thus a 1050mA combined current input and the 3W rating

I have only designed/worked with these RGB led stars in a single channel fashion  (1 regulator, 3 x transistors and only one channel/die active at any time, no color mixing).

This time I want to be able to color mix. (so have more than just one single die active at any given time)

Would I just plan on:

* using a 12v wal-wart to power this thing? Is there a better approach here? I not too keen on trying to use a 12v input source that gets chopped down to 5v (or whatever) by the vRegulators

* would I need to use 3 separate vRegulators? one for each color/channel??  (along with 3 transistors..etc)

In general what would the best approach to tackle this with?  Any other suggestions?

I'm not very clear/comfortable on making a constant current circuit for this type of set-up..

I had used (which I was told later is not the best approach) an LM317 as my base


And the:

I had followed the datasheet and was my first/only constant current anything.

If there is a better way with a different chip that is even easier to set-up (not a bunch of other components needed is a key point for me, along with easy to follow/understand wiring, since I'm just a hobbyist)   smiley

the best battery pack, that has enough voltage/current .....that allows for all components (arduino circuit, bt module and rgb led star) voltage drop....   close enough in the vF of the leds (and the vRegulator needs) so it doesnt burn un-needed heat...etc with a nice, EASY chip for making constant current circuit for the led as well..

thoughts? suggestions? feedback?

Thanks in advance!


13  Using Arduino / Project Guidance / Re: Prop "Secret agent palm scanner" (Capsense, LEDs, and 6v chime) on: June 03, 2014, 09:00:40 pm
I believe he posted pics for the IR stuff? (I didnt check up close though.. was just off top of my head)

digitalRead will give you a 1 or 0..  (ie: on or off)..  and not give you any 'range' of a value like an analogRead will..
14  Using Arduino / Audio / Re: Wave shield plays some wav files but not all, any idea ? on: June 03, 2014, 08:57:37 pm
Do the file names follow the 8.3 naming convention?

have you tried other files (with same name).. or same file with new name?
15  Using Arduino / General Electronics / Re: Reverse mounting tactile switches on: November 17, 2013, 06:57:16 pm
Maybe try the GreaseMonkey plug-in for firefox.. and the Digikey script..??

it really helps put things at your fingertips..with pics..etc..

I have looked at reverse mounted SMD LEDS before... (but never for switches.. so I'll be curious to see what you find/come up with)..

also.. a problem "I" faced (with the reverse LEDS stuff)  was:

1.) how to make the HOLE/window/cut 'legally' with the design rules?  to mount the LED (part)?  usually need to be 'xx' away from any edge.. parts not covering/outside of the PCB outline..etc.

post back on any reverse mount switches you DO find.

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