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61  Using Arduino / Microcontrollers / Re: Minimum current and voltage to run ATmega328 on: April 08, 2014, 04:04:14 pm
Hello!

I have build an object who run one 5110 LCD, one keyboard and one PC speaker. Everything get their own voltage and current from an ATmega328. What is minimum current and voltage to run this object to make it work? Is it as the schema tells? 40 mA and 5 volt?

 Your wording is pretty unclear, can you try again to restate your question. 40 ma at 5vdc is the maximum power output of a digital output pin, but I suspect that your question is more about how much current can one draw from the arduino 5V pin to power external components and modules?

62  Using Arduino / Project Guidance / Re: Servo question on: April 08, 2014, 03:58:41 pm
The signal wire (with the pulse width signal) can be connected to the servo.
The power for the servo can not be supplied by the Arduino. You need a seperate power supply for the servo motor.

How high is the risk of blowing up the Arduino?

Small risk of blowing up, as either the automatic over-current/over-temp protection of the on-board 5 volt regulator or the on-board 500 ma thermofuse if using USB power will prevent lasting damage, however you most likely end up with a very unreliable system with lots of resets, freeze ups, or other weird symptoms.

63  Using Arduino / Installation & Troubleshooting / Re: Windows 8 - I got a new computer Where do I change port number of USB devices? on: April 08, 2014, 02:10:01 pm
Because of lack of images, here is the link http://www.instructables.com/id/Arduino-Driver-set-up/?ALLSTEPS

 That is probably all correct (language issues aside) but applies to the Uno or mega rev3 driver, not the FTDI driver that the nano board uses. I noted that the FTDI website has an updated windows 8.x FTDI driver available for downloading. That is probably the path the OP needs to look into.

64  Using Arduino / Microcontrollers / Re: Can anyone recommend a ADC? on: April 08, 2014, 12:10:18 pm
That's a good point retrolefty,

But, just to confirm even a through hole dedicated ADC should *in theory* be much better than the in-built Arduino analog pins?

Does everyone agree with this?

Well the AVR analog input pins are 10 bits of resolution and single ended and the datasheet specs for the ADC sections says something about total accuracy being +/- 2 LSBs, so useful but not instrumentation quality ADC. Reading low level signals like resistance bridges is not a good match for the AVR cuilt in ADC. So AVR adc is useful but limited.

Lefty
65  Using Arduino / Microcontrollers / Re: Can anyone recommend a ADC? on: April 08, 2014, 10:27:21 am
Hi retrolefty,

Yeah, that sounds very tempting, but the person i'm building it for doesn't want any breakout boards. He wants it to be made on his own breadboard so he wants to buy the ADC directly from somewhere like Digikey.

Sucks, I know.

Well the underlining ADC chip is a TI ADS1115 available from many chip suppliers. But as it's a SMA package part not really breadboard friendly. The adafruit module supplies pins so that the module could be plugged into a breadboard. But let partner decide. Most modern parts are no longer available in DIP packages, so he is really limiting his possible solutions. This ADC is perfect for direct reading of resistance bridge devices like strain gauges without the complexity or noise sources that having to add external amplifier.

66  Using Arduino / Microcontrollers / Re: Can anyone recommend a ADC? on: April 08, 2014, 10:17:28 am
If it was my project I would ditch the  INA125 and read the strain guage directly with the following 16 bit ADC. As it has programmable gain it will perform the function that the  INA125 was performing. Again adafruit has library code to make it pretty easy to get going on an arduino based project. It is a delta sigma converter.

http://www.adafruit.com/products/1085
67  Using Arduino / Microcontrollers / Re: Can anyone recommend a ADC? on: April 08, 2014, 10:08:52 am
ADC don't really have any kind of 'error' detection, that is up to your coding logic. As far as external ADC I have good luck using one of the adafruit modules. They also offer a arduino library support code.

http://www.adafruit.com/products/1083

68  Using Arduino / Programming Questions / Re: Using External interrupts correctly on: April 08, 2014, 10:03:39 am
Getting there.

This makes no sense: digitalRead(led_bottom)>0.2)
A digitalRead() returns a high or low not a float value.

Do all your printing at the end after the finish, just save the start time in a variable to print along with the finish time and duration time calculation after the finish event.

There should probably be some timeout function in case the finish never happens.

69  Using Arduino / General Electronics / Re: Switching 220V light bulbs on: April 08, 2014, 09:34:54 am
Cheap way:

http://www.ebay.com/itm/5V-One-1-Channel-Relay-Module-Board-Shield-For-PIC-AVR-DSP-ARM-MCU-Arduino-/310566336050?pt=LH_DefaultDomain_0&hash=item484f323632

70  Using Arduino / Programming Questions / Re: Using External interrupts correctly on: April 08, 2014, 09:10:29 am
Also serial communications does not function inside an interrupt function as all interrupts are disabled at that time.
You should most likely only require one interrupt, the finished led/sensor. You can just loop in the main loop function testing the start led/sensor and when tripped capture the starting time and then wait for the finished interrupt sensor to set a flag variable the it has triggered and then again get the current time and subtract the difference to get the delta time between those two sensors and send the serial data out.

71  Using Arduino / Motors, Mechanics, and Power / Re: problem with pwm on: April 08, 2014, 08:57:31 am
Also some form of properly sized motor driver is usually required to interface the motor to a arduino pwm output pin.

72  Community / Exhibition / Gallery / Re: Vote for my data logger on Atmel's design contest on: April 08, 2014, 08:48:03 am
I voted five times!
Good luck Jack
73  Using Arduino / Motors, Mechanics, and Power / Re: DC 5V 10000mAh Lithium Ion Battery & Charger Circuit on: April 08, 2014, 08:28:02 am
I don't think there is any such thing as a 5V lithium ion battery.

Depending on the chemistry,  battery cells have a characteristic voltage based on the chemistry,  and multi-cell batteries are multiples of that voltage.  For example,  Lipo batteries have a nominal voltage of 3.7 volts, or 7.4 volts, or 11.1 volts .....   not 5V

Also,   the capacity of a charger is determined by it's current supply ability,   not the size of the battery.   For a specified charger output current,  bigger batteries just take longer to charge.

3.7 volts would be fine. I just don't want to use a polymer battery because of the fire danger.

 Lithium-ion and lithium-polymer batteries share the same concerns as far as charging/discharging/fire risks and other safety concerns. The poly cells tend to have more vulnerable packaging so possibly more vulnerable to mechanical damage, but both need the same care in charging and discharging practices.

http://en.wikipedia.org/wiki/Lithium-ion_battery

http://en.wikipedia.org/wiki/Lithium_polymer_battery
74  Using Arduino / Motors, Mechanics, and Power / Re: Micro servo 9 grams on: April 08, 2014, 08:09:31 am
Also keep in mind that the actual current drawn by a servo is variable and depends on several things:

Model/size of the servo
Mechanical load attached to the servo
travel distance commanded to move.

The separate power supply or batteries used to power the servo(s) should be sized for the worst case condition that the servo(s) will be subjected to. A current 'budget' of 1 amp current capacity per servo is a good starting point.

75  Community / Bar Sport / Re: Your latest purchase on: April 07, 2014, 04:52:43 pm
me too, I've got a few UV-Eproms just to be able to build old fashion boards equipped with Z80 and 68000 CPU  smiley-grin

also i've got a pretty USB-UV-Eprom programmer  plus an UV eraser smiley-mr-green:

 I believe I read in the old days if you just left them outside in the sunlight for a couple of weeks that would erase them also.

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