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1  Using Arduino / General Electronics / Re: Rotary potentiometer with steps/positions on: February 01, 2013, 11:45:22 am
Ah, of course, thanks!

I think I might need to buy a Mega since I'm running out of pins. smiley
2  Using Arduino / General Electronics / Re: Rotary potentiometer with steps/positions on: February 01, 2013, 11:27:32 am
Thanks for the suggestions and ideas. For me I guess a normal pot would be ok since I only need to. Switch between 2-3 pages.

Now the next question. Can I use a digital (pwm) pin for this? This can be made to know what position the pot is right or do I need an analog pin?

What type of pin should I use for a rotary encoder?
3  Using Arduino / General Electronics / Rotary potentiometer with steps/positions on: January 31, 2013, 09:27:52 am
Ok, this is probably not the "correct" way of describing it so please bear with me. smiley

I'm looking for a rotary potentiometer that has pre-defined "steps/positions". I'd like to use it to change pages on a LCD-screen, each position of the potentiometer would be one page. The "feel" would be a lot better if I could match each page with a defined position on the knob.

It would be good if it had the aprox same dimensions as this one since I have a  number of knobs for it.
Pot: http://www.ebay.com/itm/221132272705?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648
Knob: http://www.ebay.com/itm/321038173376?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648
4  Using Arduino / LEDs and Multiplexing / Re: Strange RGB LED problem on: January 19, 2013, 02:37:41 am
Below my messange also the reply from the seller.

Quote from: boopidoo
These LEDs are not common cathode. Well the green and blue is common cathode but the red LED seem to be mounted to other way so it only works if current and ground is reversed.

I'd like a new shipment of correct, 100% working, LEDs.

Quote from: dasetn
Hi, Simon I'm very sorry, I know this problem. At present I have corrected the mistake, the reason is I suppliers provide goods wrong to me, and I didn't see. Don't worry, I will resend new item to your address, water clear RGB led... Hope to understand, sincere thanks! Any question can email to contact me

So lets see how the new ones work out. However the question is how many newbies like me think they themselves make an error and doesn't bother to send a message, get stuck with bad ones and looses interest because it just doesn't work?

But they're 10pcs incl int shipping  for $2.99 so I don't complain. smiley
5  Using Arduino / LEDs and Multiplexing / Re: Strange RGB LED problem on: January 18, 2013, 02:19:28 pm
Quote from: Forrest Gump
Buying LEDs from China is like a box of chocolate, you never know what you're gonna get.
6  Using Arduino / LEDs and Multiplexing / Re: Strange RGB LED problem on: January 18, 2013, 01:38:48 pm
As I wrote the LEDs does light up but only blue and green when connected as a common cathode and red when connected as a common anode.

I know the values are too high, I calculated 75ohms for G&B and 150ohm for R but I didn't have those right there and then so I used what I had using twice as high value for R then G&B. I can't imagine that using too high resistor values would invoke this behaviour, if so please explain how?

Also for testing they are indeed quite bright as is so I guess it would be close to unbearable using R that are 7 times lower. smiley
7  Using Arduino / LEDs and Multiplexing / Re: Strange RGB LED problem on: January 18, 2013, 06:50:38 am
Maybe they were indeed wrongly assembled. I guess this behaviour would be explained if the somehow mounted the RED LED the wrong way.
8  Using Arduino / LEDs and Multiplexing / Strange LED problem (faulty RGB LED on eBay) on: January 18, 2013, 04:47:24 am
I'm guessing the more experienced ones will be able to answer this in a heartbeat.

I have bought this set of common cathode RGB LEDs: http://www.ebay.com/itm/321029238303?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Despite what the ad says they are not clear and maybe they're not even common cathode?

Anyway I've made a sketch in Fritzing which shows my connections. The resistor values for Red is 1k and for Green and Blue is 470 each. The problem is that like this it only light up green and blue, not red.

When I connect it the exact same way but connect to 5V instead of ground, like a common anode, the red lights up but not green and blue.

I have a common anode RGB LED which works perfect when connected like a common anode.
9  Using Arduino / General Electronics / Re: Voltage divider problem on: January 11, 2013, 04:58:41 am
What if I removed the caps on RX1 & RX2-inputs and placed resistors in series with the ground (to eliminate ground loops) or eliminated the ground for RX1&2 inputs altogether.

The ground on the RX1&2 is from two devices that is powered from the 12V-source which I am monitoring so that ground is already connected.
10  Using Arduino / General Electronics / Re: Voltage divider problem on: January 10, 2013, 12:47:10 pm
Well maybe I'm just lucky but I'm actually very happy with the measurements which are within 0.01V from what my volt-meter measures. This has now been tested between 4-12V and between -5 to +25 degrees C. If this is consistent I don't need the results to be any better in this project.

The measured voltage on my Arduino doesn't seem to change noticably when I add a volt-meter to the circuit and vice versa.

Now my problem is making the PCB which was harder then I imagined... a real puzzle. smiley
11  Using Arduino / General Electronics / Re: Voltage divider problem on: January 10, 2013, 08:20:51 am
Ok, so I should be able to remove these without having signal problems? If they don't do anything good then it will simplify my wiring and PCB-shield a lot.
12  Using Arduino / General Electronics / Re: Voltage divider problem on: January 10, 2013, 02:38:53 am
Quote
Is there a risk when adding a cap when it's not really neccessary?

Yes.


This is my current breadboard. I drew it so it shows the connectors I plan to use. The caps I'm talking about are the ones that are placed for each analog input.

13  Using Arduino / General Electronics / Re: Voltage divider problem on: January 09, 2013, 04:25:04 pm
Is there a risk when adding a cap when it's not really neccessary?
14  Using Arduino / General Electronics / Re: Voltage divider problem on: January 09, 2013, 02:31:04 pm
Put a small capacitor on the analog input pin. Anything from 0.1n to 1000n will work.
When should I use a capacitor like this? On all analog inputs? I have some inputs that goes straight from a 0-5V source and thus doesn't need a voltage divider but do I still need the capacitor?

Also should I route both ground and + from this source? I also monitor its voltage so I guess there's a risk of ground loops.
15  Using Arduino / General Electronics / Re: Vin not the same as input voltage on: January 08, 2013, 10:08:16 am
Ah ok, so in theory I could compensate for this voltage drop in code. But I guess it would be more exact to read the voltage from the source instead.
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