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466  Using Arduino / Networking, Protocols, and Devices / Re: RN-41 bluetooth with an arduino on: March 31, 2011, 09:00:16 am
How do you wire it up?  Isn't it 3.3v, and the Uno 5v?  I thought you'd need at least a step up/down regulator.
Here's the schematic off the datasheet.  Could someone post a schematic of the minimum/simplest way to connect this to an Uno? 
467  Using Arduino / Networking, Protocols, and Devices / RN-41 bluetooth with an arduino on: March 30, 2011, 11:06:07 pm
Is there a tutorial or guide to using the RN-41 ( an Uno or other arduino?
The RN-41 only costs $25 at Sparkfun, but the Bluetooth Mate Gold costs $65...  If is just a few components different and the knowhow to hook it up, I can supply the first, but the knowhow?  I've searched quite a bit, but there's just not much out there.  There must be more to it that I don't understand?
468  Using Arduino / Displays / Re: lifetime of header pins on: March 29, 2011, 10:11:02 pm
So, I might do better using standard pins from Sparkfun.  The pin do make a good sliding contact, so I'm good on #8.
For #3, the lubrication: I have some of this anti-oxidizing lube you use in panel boxes with AL wiring, that might be a good thing to smear a little in the Uno headers?
469  Using Arduino / Displays / Re: lifetime of header pins on: March 29, 2011, 09:55:33 pm
What if I use gold plated pins like these.  Shouldn't they hold up well in the Uno?  I'm not wanting to use an alternative, if something like this work.
470  Using Arduino / Displays / lifetime of header pins on: March 29, 2011, 08:13:32 pm
Will the header pins on an Arduino Uno last 5-10 years in a permanent install?  The project will be indoors, climate controlled, dry, and no vibration.  99% of the time the only power drain on it will be a 16x2 LCD display.  I will be using a custom shield on the header pins.
471  Using Arduino / Project Guidance / Re: Using an Uno in a long term project on: March 29, 2011, 11:46:01 am
...are you sure these won't fit into an uno?
There's no specs on them, but the specs for the matching header shows .51 mm
My basic question/corcern is:  Is a header/pin connection good for long term use?  That's all I'm worried about.  That's why I thought I'd get the better pins.
472  Using Arduino / Project Guidance / Re: Using an Uno in a long term project on: March 29, 2011, 11:20:31 am
Hmmm, so if I use the stackable header pins:
...will this hold up for long term use?
473  Using Arduino / Project Guidance / Using an Uno in a long term project on: March 29, 2011, 10:57:45 am
I'm wanting to use my Uno with my home brewed shield for a home automation project.  I am planning on using SparkFun's high quality, machined pins for connecting to the Uno.  Will this connection be suitable for long term use? (5-10 years)  The project will not be subject to vibration, etc.
474  Using Arduino / Motors, Mechanics, and Power / Re: Driving a solenoid on: March 29, 2011, 10:45:06 am
Thanks for explaining that for me.
475  Using Arduino / Motors, Mechanics, and Power / Re: Driving a solenoid on: March 29, 2011, 09:57:58 am
Here is a very nice logic level mosfet available in the US.
I am using this as in the drawing in post #6 (with the source and drain corrected).  But Sparkfun's example has R1 setup up different, in this example:

Is one better than the other, or will they both work the same?
476  Using Arduino / Displays / Re: Power source on: March 28, 2011, 01:16:12 pm
Thanks, I thought so, but wanted to be sure.
477  Using Arduino / Motors, Mechanics, and Power / Re: Using the SN754410 on the adafruit motor sheild on: March 28, 2011, 12:39:20 pm
On using the SN754410: Some people use the SN754410 motor driver chip because it is pin-compatible, has output diodes and can provide 1A per motor, 2A peak. After careful reading of the datasheet and discussion with TI tech support and power engineers it appears that the output diodes were designed for ESD protection only and that using them as kickback-protection is a hack and not guaranteed for performance. For that reason the kit does not come with the SN754410 and instead uses the L293D with integrated kickback-protection diodes. If you're willing to risk it, and need the extra currrent, feel free to buy SN754410's and replace the provided chips

What if I add my own flyback diodes (1N4007), would it then be perfectly safe to use the SN754410?
But is it possible to add these diodes to the circuit and still maintain a reversible motor?

Look at the datasheet:

Also look at the datasheet for the L298N for how to hook up the diodes (it has a clearer diagram for DC motor h-bridge control).

Basically, the connection for a DC motor is (bad ascii art ahead!):

O1 ---------------+
             D1   |    D2
    GND ----->|---+---->|---- +VS
             D3   |    D4
    GND ----->|---+---->|---- +VS
O2 ---------------+

Where O1 and O2 are the outputs from the h-bridge, D1-D4 are the diodes, GND is ground, and +VS is the DC supply for the motor.

The only thing about the datasheet for the SN754410 is that it doesn't say whether to use high-speed Shottky diodes or not; the 1N4007 is not such a diode. It might work OK - I'm not sure (go for Shottkys if you can for this app - they don't really cost all that much more).

Thanks for this info.  I'm adding it in now, can you take a look at this drawing and make sure I've got the diodes oriented right, going to ground or voltage at the right places...
478  Using Arduino / Displays / Power source on: March 28, 2011, 11:02:25 am
I'm powering my SparkFun 1602 LCD from a 7805, powered by a +12v adapter.  I'm also powering my Uno from the +12v adapter.  So the ground is common to the Uno and the LCD. 
My question, if my voltage into the Uno goes to the Vin and Gnd pin right next to it, can I safely use the ground pin next to D13 to ground my LCD, and LCD backlight?

In simpler terms, the voltage my LCD uses has to get it's ground by going back to and through the 2 ground pins on each side of the Uno board.  This should not be a problem for the amount of current an LCD uses should it, nor will it cause any type of inductance or something that I don't know about?
479  Using Arduino / Displays / Re: Quick urgent PWM question on: March 26, 2011, 11:34:40 pm
Thanks for the good schema, rugged!
480  Using Arduino / Displays / Re: Using Pin 13 for LCD on: March 26, 2011, 11:32:30 pm
With a very tight home pcb in the making, it's quite beneficial to use pin as the enable instead of an other.  If you haven't had any problem with DAC, I doubt I ever will with the LCD...
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