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5 minute timer where a mechanical motion is required


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hi i am new and require urgent help on a project. my problem is that i have to light up 5 2.3v(.027amp) globes with a 9v battery. but the catch is that i need to create a switch through water. where as water rises through a cylinder it will complete circuits turning on the globes. i would very much appriciate help. i know that the circuit requires current amplication but i have no idea how to go about this.
note (could u specify the parts i need)thank you

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Hi Iceman,
Welcome to our forum. ;D
Your battery's voltage is much too high for 2.3V globes. If it is a little 9V "transistor radio" battery then it won't power 5 globes through voltage-reducing resistors for very long. You should use two C cells or D cells in series. Most two-cell flashlights use 2.4V globes.
2.3V/0.027A = 85 ohms for each globe. Five of them equals a load on the battery of 17 ohms. See the datasheet attached of the battery for its short life.

You can switch the globes on with floats attached to micro-switches.
If you don't want floats and switches then you need to make 5 two-transistors circuits. ;D

post-1706-1427914235918_thumb.png

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ok thanx for the info guys. but i have never really done electronics before so i'm not really sure of what it is that i need to do.
but here is my circuit i am building. it is running off 2d batteries. and not the switch is only two wires in a perspex cylinder(all 10 wires in and out of the cylinder will run through the same water). i did a quick sketch of the circuit.

post-11696-14279142359918_thumb.jpg

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yeah but i need each globe to turn on at certain level. i.e the 1st globe at a water level of say 2 cm, then the next globe when the water level reachs say 4 cm, but still keeping the 1st globe on. so what will happen essentially is that a globe will turn on after water completes a circuit (keep it on) and then as the water increases in hieght the next one will turn on and so on. i hope that someone out there can help me coz i got no clue! i am a designer not an electrican.  :'(

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maybe this is stupid but has no-one thought of adding a little salt to the water to make it a little more conductive. instead of using transistors for this is possibly just a small project. so try using the said battery conecting the globes up the way you need to and put the probes into the water then add the salt and stir.

sound like a cooking recipe

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Has no-one thought of adding a little salt to the water to make it a little more conductive. instead of using transistors for this is possibly just a small project.


Yes, I thought of adding electrolytes to the water such as salt.  Fill a small cap with water and measure the resistance.  The range is 400k to 1.5M Ohms.  Add salt to this water.  Add a lot of salt.  The range is 20K to 30K Ohms.  This require 500v to pass only 20mA of current. 

iceman302:
By the way, is the water solution independent?  May the water's contents be altered or is this to actually monitor real world liquids such as pool, fishtank, bath, sink.....?
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the project i am doing is a 5 minute timer where a machinical motion is required. mine is water helped by gravity and pressure. the project states that the timer must show minute incrimant. thus my design was to have water filter across so as in rises in cylinder 2 it will complete circuits turning on lights to indicate each minute. also there is no limit or restrictions on materials or methods. just that no motors are allowed. my question is will salt work???

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