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1  Using Arduino / Microcontrollers / Re: Unable to use USBtinyISP on a bread board ATMega328p set-up on: April 16, 2014, 06:34:42 pm
I recall reading in the past that USBtinyISP had some problems in uploading to ATMega328p's due to the ATMega328p's having more memory than USBtinyISP was prepared to deal with.  I did a quick google search and found:

Nick Gammon also had this to say:
2  Using Arduino / Project Guidance / Re: Video-out to a 640x480 LCD display on: April 16, 2014, 03:23:06 pm
Hehe.. Maybe an Intel Edison would be your ticket.
IIRC, the Galileo board that has the Edison chip and runs the Arduino libraries has some fairly high power requirements that would make it undesirable for mobile apps that need to run off of batteries.  Lets see you will need a 5 volt battery (easily doable) that can put out 3 amps of power (much harder to find).
3  Using Arduino / Project Guidance / Re: Video-out to a 640x480 LCD display on: April 16, 2014, 12:29:25 pm
Video is not simple.  It has fairly high bandwidth requirements that are just beyond what a 16Mhz Arduino with limited memory can handle.

Rather than getting a web cam, get a camera that outputs composite video directly, such as the cameras made for car backup systems.  You should be able to hook this camera straight to the Myvu, which appears to have a connector for the yellow RCA plug for composite video.  Here is the first such camera I found on ebay:

If you have an Uno, you might be able to use the Video Experimenter's shield to overlay some basic text information over the video stream.  It won't work with Leonardo or Mega processors.  I bought one a few years ago, and never used it.  As I recall, the source available was made for pre-1.0 Arduino libraries, and you needed to make some minor mods to get it to compile:
4  Using Arduino / Project Guidance / Re: DSLR Intervalometer with Arduino Uno on: April 15, 2014, 11:08:10 pm
I don't know if you remember their ad.. "You have questions. We have answers."
I always found it was more like "You have questions. We have blank stares."
I don't remember the ad, but it is kind of sad.  They are trying to re-invent themselves, but unfortunately, I'm not sure in the day of ebay, whether they will be able to survive.  And getting skilled clerks is a problem....
5  Using Arduino / Project Guidance / Re: DSLR Intervalometer with Arduino Uno on: April 15, 2014, 10:52:35 pm
Well the pinouts are fairly simple.  Here is a list of the pinouts of the various camera's cables:

As you can see, the 2.5mm cable has 3 wires.  The one closest to the cable is the ground, the middle one is the focus, and the tip is the fire control.  If you connect the ground wire to the middle wire, it should cause the camera to focus (do the 1/2 press of a shutter release).  On some cameras, you will need to connect the ground to both the focus and fire wires to shoot, on some you only need to connect the ground to the fire wire to shoot.  It is fairly easy to use a metal wire or even screwdriver to determine which method your camera uses (my Olympus cameras need both connected).

The basic idea is to have one pin on your Arduino that connects the ground to the focus wire, and another that connects the ground to the fire wire.  I use an opto-coupler so that the Arduino is electrically separate from the camera (the camera provides a weak current through the wires, and when the circuit is completed, it does the action).  You probably could use transistors instead of opto-coupler, but I started with an opto-coupler, and I prefer the extra layer of isolation (an opto-coupler has a led inside with a photo trigger, so the Arduino and camera never have wires connected together).  Recently, I've been using CNY74-2 optocouplers with 220ohm pull-down resistors, but you might want to use this unit which is more self contained:

On the left side, you would connect a 5v wire from the Arduino to VCC, ground to the ground connection, and the 2 pins that will control the focus and fire to CH1/CH2.  On the right side, you would connect the ground wire to both - terminals, and connect the focus to the CH1 + terminal, and fire to the CH2 + terminal.  You would then need to write a program that uses digitalWrite on the 2 pins to control the focus/fire buttons.

If you live in the USA, and still have a Radio Shack nearby, they have 2.5mm terminals, that you plug a cable into and it has 3 connections to solder wires to:

Typically you need to go to the back of the store to find the gray cabinets of doom, to search through for the connector.  If you are lucky, the clerk can help with the search (many RS clerks have no knowledge of these type of electronics).  Initially you can just twist the wires instead of soldering.  Or you can just cut up a cable.

You need a tool like a multimeter (or a simple connectivity circuit that has a led with a resistor connected to a battery, and the led lights up when the circuit is complete -- you use this to identify which wire is which).

6  Using Arduino / Project Guidance / Re: Simple Finger Switch on: April 15, 2014, 05:57:20 pm
What you want to look into is called capacitive sensing.  Here is the playground post listing the capacitive sensor library:

If you are using the Teensy 3.0/3.1 processors, they have some pins that do capacitive sensing directly:

Adafruit has a stand-alone momentary Capacitive Touch Sensor Breakout: and a toggle version:  They also have an i2c version that has 8 wires:

Alternatively, you could get a membrane keypad that doesn't require as much force to press:, or various force sensors:

Or a photo sensor, that when you put your finger over the sensor reports less light: or a short range proximity sensor:
7  Using Arduino / Project Guidance / Re: Before i waste time and money... on: April 10, 2014, 11:19:14 am
Trinket can control two servos easily.  There is a small bot on with two servos and there have been posts of other small Trinket bots.
However an off the shelf servo will only go 1/2 rotation (180 degrees).  You can get servos that are modified for continuous rotation, but there you don't have the precise control (you control the continuous rotation servo's speed and direction, but it may not give you the fine control that the OP seemed to want).
8  Community / Bar Sport / Re: OSH Park Teensy 3.1 for $17! on: April 07, 2014, 04:47:54 pm
Interesting. I should probably get one just to try it out. How about their support?

Question: What do you use DMA for on this device? What high speed devices?
For Teensy 3.x support, go over to and judge for yourself.  Look for the posts of Paul Stoffregen, the creator of the Teensy 3.x.  Paul's OctoWS2811 library for running many, many WS2812/WS2812B lights (Adafruit calls their version neopixels) uses DMA.
9  Using Arduino / General Electronics / Re: Safe to connect both VIN and a USB connector? on: April 03, 2014, 02:34:49 pm
It is a problem if the chip isn't designed for it.  However, if you have an official nano, then it in theory should be supported.  Quoting from:

The Arduino Nano can be powered via the Mini-B USB connection, 6-20V unregulated external power supply (pin 30), or 5V regulated external power supply (pin 27). The power source is automatically selected to the highest voltage source. The FTDI FT232RL chip on the Nano is only powered if the board is being powered over USB. As a result, when running on external (non-USB) power, the 3.3V output (which is supplied by the FTDI chip) is not available and the RX and TX LEDs will flicker if digital pins 0 or 1 are high.
10  Community / Products and Services / Re: Amazing Sale...Arduino's for $3!!! on: April 01, 2014, 12:21:46 pm
In case you haven't seen it, Sparkfun got almost 8,000 orders on Saturday, and it bolixed up some things (my order is listed as being in 'exception' state).  I figure I will ping them if it doesn't change to either shipped or back-ordered in a few days:
11  Community / Products and Services / Re: Amazing Sale...Arduino's for $3!!! on: March 29, 2014, 10:15:46 pm
Huge Arduino Sale.... Figured I would share it with everybody! When is the last time you got an Arduino for $3? I ordered 8!
Umm, you were supposed to be able to order only 2 of each model, and only 2 of them are $3 each (5v pro mini and 3.3v pro mini).  So at the $3 price, you should have been able to get 4 boards.  And note that you will need some way of programming the board (FTDI, etc.) that is not included in the board.

It is a good deal, though with the backorders now, I wonder how fast Sparkfun will restock, and whether you could get a similar clone from a Chinese vendor faster than from Sparkfun (of course Sparkfun does pay some amount back to the Arduino folks on these boards, and the clone vendors don't, but with this sale, I have to imagine the Arduino folks won't see much revenue from it).

I'm sure lots of people took advantage of the sale honoring internal Arduino day.  In fact, I happened to be up about 1/2 hour after it began, and saw that the official Uno's, the redboards, and the pro minis were all sold out, but they had 400 or so of the 5v pro minis (the $3 item), and a couple hundred of the 3.3v version (the other $3 item).  I went to bed, and a couple of hours later, Sparkfun had fixed the bug that prevented back orders, and all of the Pro Minis were sold out.
12  Community / Exhibition / Gallery / Re: High speed vector graphics engine. 3.2" TFT Lcd screen. on: March 29, 2014, 04:10:12 pm
I dunno, if you have a need for speed, the first thing you should do is move up to a faster processor.  You can get Arm processors that support the Arduino libraries that run 4-8 times faster than a Mega (Teensy 3.1 runs at 96Mhz compared to 16Mhz for the Mega, and given the Teensy is a 32-bit processor, it means it does things in fewer cycles, which gives you an additional boost in speed).

Then if you are willing to change platforms, the Linux SBC's (single board computer) will run much, much faster, and they have hardware floating point in case you need it (Beaglebone Black runs at 1Ghz, Rasberry Pi at 700Mhz).
13  Using Arduino / Project Guidance / Re: Voltage regulator suggestions for ATmega328? on: March 29, 2014, 04:03:16 pm
Unless you actually wire up the enable pin, I don't think these regulators go to sleep automatically.  You have to explicitly tell them to go to power saving mode, at least that is the impression I got scanning the spec sheet.
14  Development / Other Hardware Development / Re: Tips for multi-voltage shield with I2C/SPI/Serial on: March 27, 2014, 08:36:29 pm
You might want to look at what digistump (makers of digispark ATtiny85 and digix Arm boards) did in their level shifting shield.  Or perhaps you can use it as is:
15  Using Arduino / Interfacing w/ Software on the Computer / Re: Searching Android compatible product on: March 27, 2014, 11:49:35 am
You might check for the Android Apps ArduinoCommander and ArduinoDroid, which might do what you want.  Note, this forum is more for announcing new products.  You probably want to post future questions in the General Guidance forum.
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