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871  Using Arduino / General Electronics / Re: Ohms calculation question on: September 22, 2013, 07:45:38 am
You'd need a magical resistor to get 7v from a 5v output...

872  Using Arduino / Project Guidance / Re: Reset switches relay on: September 22, 2013, 07:43:47 am
if you're powering a relay directly (eg, not an expansion board which requires a 5v input), yes it's a no no.
873  Using Arduino / Project Guidance / Re: How to detect a coin falling? on: September 22, 2013, 06:35:47 am
if you consider what an Arduino can do and calculate in the time it takes a coin to travel from top to bottom is pretty impressive.

874  Using Arduino / Project Guidance / Re: Arduino Mega + 1307 Time Clock gains almost a minute per day! Help! on: September 22, 2013, 06:34:20 am
I purchased a couple of these back in March/April. I set them once when they first arrived. They still seem to be correct to within a minute.
http://www.ebay.co.uk/itm/mini-RTCpro-DS3231-high-precision-clock-module-environment-temperature-measure-/390521397685?pt=LH_DefaultDomain_0&hash=item5aece3a1b5


The right-angle connectors came soldered on. They were a b****rd to get off!

Heat gun or as my soldering instructure said heat every pin with the soldering iron, then simply pull each pin out one at a time, it's a bit time consuming but it worked great for me... or simply use a heat gun.
875  Community / Bar Sport / Re: To become an "expert" with electronics... on: September 22, 2013, 03:34:26 am
Nope, because who in their *right* mind would spend 30 years learning the same material over and over?...

Your logic only works if the person is mentally ill.
876  Community / Bar Sport / Re: To become an "expert" with electronics... on: September 22, 2013, 12:24:56 am
Quote
Spend 30 years doing it only half arsed
You can spend 60 years doing it half arsed and you will only ever be an half arsed expert.

Your logic is incorrect.

If you spend twice as long spending 50% the effort as someone spending 15 years putting 100% effort into it...

Then after 30 years you'll still be an expert....
877  Using Arduino / Project Guidance / Re: Arduino Mega + 1307 Time Clock gains almost a minute per day! Help! on: September 22, 2013, 12:20:21 am
http://www.ebay.com.au/itm/1-Pcs-INBOARD-RTC-DS3232-Real-Time-Clock-and-Temperature-Sensor-I2C-BUS-PIC-/360672379910?pt=LH_DefaultDomain_0&hash=item53f9bfc406


It really is get what you pay for, next step up would be an atomic clock to keep your time accurate.
878  Community / Bar Sport / To become an "expert" with electronics... on: September 21, 2013, 10:05:50 pm
I kinda get the feeling you need at least 15 years experience to become an expert or....


Spend 30 years doing it only half arsed lol....
879  Using Arduino / Project Guidance / Re: Arduino Mega + 1307 Time Clock gains almost a minute per day! Help! on: September 21, 2013, 09:42:42 am
Nope these ebay rtc clocks are that bad.. i used an ethernet shield or serial usb to update time every few hours or modify the circuit slow the crystal...


880  Topics / Home Automation and Networked Objects / Re: Looking for arduino controlled 220V outlet or powercord on: September 21, 2013, 09:35:12 am
Buy a relay board which connects to arduino... it's easy enough if you think about every step of the build.
881  Using Arduino / General Electronics / Re: Jump cables? on: September 21, 2013, 09:30:56 am
Generally strip and tin your wire unless it's single core wire, and connect if they're close enough a solder bridge... picture?
882  Using Arduino / General Electronics / Re: 50% duty cycle square wave from 1hz to 1Mhz, easiest way? on: September 21, 2013, 09:26:16 am
Between pins 6 & 7 place a diode to get a 50รท duty cycle...

View my attached image, replacing the resistor(s) for potentiometers will give you what you need, a low pass filter on the output should stop noise...

Seems easy enough... view attached image
883  Using Arduino / General Electronics / Re: question about the current going into 7 segment ! on: September 21, 2013, 07:56:06 am
Splash out on 7 more resistors and hook them to each segment...

yes of course resistor should be connected to segment but my question was about the common which means 1 resistor in addition
in total will be 9: 8 to segments and 1 on the commons so is that a right thing to do ?

it simply means it wont be equal brightness of all the segments (some segments will be dimmer/brighter) and the less lit up the brighter it becomes ...

the only concern would be 1 segment consuming more than it should potentially damaging it, but you said 1k resistor ? then no....
884  Using Arduino / General Electronics / Re: replacing the pnp for npn? on: September 21, 2013, 06:30:49 am
ohhh right, it's all about energy conservation ...

The idea was to use 2 npns, but if it's purely down to the voltage drop (which in turn would lower the current draw (lower voltage) )

screw it, use an LED!
885  Using Arduino / General Electronics / Re: replacing the pnp for npn? on: September 21, 2013, 06:29:45 am
Here's the changes i made..

I've not emulated or built it.... but considering how long it just took me to use ms paint to edit that thing to do that circuit, i'd have been better of emulating the circuit..

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