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1  Using Arduino / General Electronics / Re: 8v2a to 16v1a on: August 07, 2011, 01:36:58 pm
Well, I messed arround some more,  I boosted it to 24 volts, and still I only got 2v at the other end?, then I tried CrossRoads sugestion and lo and behold the signal got through, so I am going to have to do it that way. Thank you CrossRoads. I actaully used the tip120 as a relay, it works just fine.
2  Using Arduino / General Electronics / Re: 8v2a to 16v1a on: August 05, 2011, 01:58:49 pm
This is my current layout, but it has 4 bells, this layout only shows 2, it works just fine, as i understand it, the 25m would lose a small 5v signal. it lost the 8v, all i was getting at the other end was about 1v. I would like to try to keep it all running under 1 power suply if i can.

The fets are actually tip120 transistors.
and the speakers are obviously the bells.
3  Using Arduino / General Electronics / Re: 8v2a to 16v1a on: August 05, 2011, 01:18:09 pm
Hopfully image will attach, so if i laid it out on a bread board like the pic, that would work?. Bells use 8v, but i have seen them ding on about 6v. The voltage has to go a long way, total 50m round trip, so there is a lot of drop off, to much voltage is no problem i believe, but to little and nothing will happen. I will only ding one bell at a time, obviously, i will only double it for the bells that are far away.
in the drawing, (dont fully understand them) which way is + on the capacitor, I am assuming the top is + (the long wire).

When you said, current, do you mean amps, I think its 8v1a, because the transformer to run one is that, and to run 2, its 8v,2a.
4  Using Arduino / General Electronics / Re: 8v2a to 16v1a on: August 05, 2011, 11:28:24 am
thank you, so if i was to use the Greinacher circuit, the transformer being 8v2a ac, what capacitors should i use, i dont know how to calculate it, i have some 220uf 16v + 470uf 16v, are any of them any good?
5  Using Arduino / General Electronics / Re: 8v2a to 16v1a on: August 05, 2011, 10:48:09 am
I have a door bell that i built, it has 4 mechanical ringers, hence the 8v,2a transformer, but 2 of the bells wont ring because they are to far away and the power drops off to much, so i figured, if i used the arduino, i could.
A, ring the bell for as long as i wanted off one bell push.
B, Only ring one bell at a time thus giving maximum power to each dome/bell.
C, Increase the voltage for the far away bells so that they will actually sound

At the moment i have the arduino set up to cycle through all four bells on 12v dc power, all is well, but i know that when i put it onto the wire that is 25mX2 long, 12v most likly wont be enough.

At the moment I have a 1.5v-12v wall wart that i am using, but i have the transformer that i bought for the bell, which is 8v2a, and i think it might be ac, a rectifier is no problem i believe.

The other thing thats quite cool about using the arduino as a door bell is that i could put an lcd on it and have it say somthing when someone pushes the bell.
EG, not in at the moment, leave any parcels at no 10's, or ring this number, if ur a sales man, piss off. lol.
Obviously you use a switch to change th emessages easily, or a key pad. what ever, for now, I just want the damn bell to ring when i am at the bottom of my garden, which is often as my workshop is there.

Cost wise, the arduino is actually quite a cheap way of getting a complex customised door bell working.
6  Using Arduino / General Electronics / 8v2a to 16v1a on: August 05, 2011, 09:32:19 am
I have a transformer that puts out 8v2a, I want to make it put out 16v, from what i understand (limited) this is possible, but how would you do it.
7  Using Arduino / Motors, Mechanics, and Power / Re: tip120 reduces power? on: August 05, 2011, 08:38:32 am
I know the pic shows a mosfet, but it should be a tip120, (the program that generated that, fritzing, only has a mosfet model), I put a 10k resistor in, and turned the volts up, its actually a bell i am running, so it needs atleast 4 volts. I still get low voltage readings, but it does seem to be putting out the right power as the bell would not work on such low power.

I have an 8v/2a transformer that i want to use, i think it might be ac, but i can just put a rectifier in if it is (i think), how can i convert that to 16v/1a easily. The reason being, the bell wire is about 25m*2 long, and the voltage drops to much for it to work, so i figured that if i doubled the voltage, it might work.

I actually intend to run 4 8 volt bells, cycling through them dinging them for a second or so each, thus distributing the smaller transformer across them all.

Anyone know why the board wont upload when the grounds r joined ?
8  Using Arduino / Motors, Mechanics, and Power / tip120 reduces power? on: August 04, 2011, 07:32:21 pm
i used this as a base for a project that i am doing, i have now copied this exactly, without the pot.
http://itp.nyu.edu/physcomp/uploads/arduino_bb_pot_transistor_motor_diode.png

Instead of getting lots of extra power, im only getting about .2 volts to the motor.

I tested the voltage at at the collector, its 6v*,  when no power is sent to the base, 0.9v when power is applied to the base.
I tested the voltage at at the Emitter, its 0v when no power is sent to the base, 0.1v-0.2v when power is applied to the base.

I am using exactly what they say here, the tip120, (i have tried about 5 tip120s, so i doubt its a fault with it)
http://itp.nyu.edu/physcomp/Tutorials/HighCurrentLoads

I also noticed that when i share the grounds, i can no long upload to my arduino (uno)

*or 7.4v if i turn up the wall wart, just confirming power is comming from the wart.

Anyone got any ideas, cause i am stumpped.

Added l8r
Well, it seems that although the readings are wrong, i do seem to actually be getting higher voltages, anyone know why its not reading correct. or why you cant upload with shared grounds.
9  Using Arduino / Sensors / Re: analogread is this right on: June 27, 2011, 10:42:37 am
I worked it out, what a noob i am, i had it in digital ports, not analog.
10  Using Arduino / Sensors / Re: analogread is this right on: June 27, 2011, 09:34:13 am
Now that i know what to look for, i managed to research the floating data, thank you.

as for what was i talking about,
http://www.instructables.com/id/Arduino-Expermentation-Kit-How-to-get-Started-wi/step11/Light-Photo-Resistors-CIRC09/

simple sensor circut. I have the booklet, i thought it came with all arduinos smiley.
11  Using Arduino / Sensors / analogread is this right on: June 27, 2011, 08:42:53 am
I was quickly testing circ 0-9 in the little book(photo resistor example), but it didnt work, after much buggering arround I worked out that the analogread just returns jibberish even if there is nothing attached to the pins.

it returns random numbers between 250 to 400 roughly

for(Ctr=0;Ctr!=13;Ctr++)
 {
 lightLevel=analogRead(Ctr);
 Serial.println(lightLevel);
delay(500);
}

I accept that maybe my little photsensor is buggered, is it normal for the analogread to return nonsense if nothing is plugged in. I would have expected it to be zero.
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