Water Drop Sensor

[Roff]

Here's a possibility. If you have reversed the base and collector connections, it will burn out the PIC and light the LED. Check the datasheet. The base is not the center pin.

 

[atntias]

im pretty sure i didn't, i cant tell for sure because i unsoldered it, but as i remember it i did check the data sheet and soldered right...
is there a safe way to check things out with out taking the risk of burning it shuld work and i cant tell what went wrong... maby didodes but where?

 

[student1616]

with out the TIP41,ur trying to sink large amount of current in to the PIC.thats why it burned off.u shld always use some protective transistor after the PIC pin.and regarding the connections....
base will go to PIC,emitter to ground and LED will come between supply and collector.try this bcz it worked every time for me.iam using tip122.

one doubt.how can u make the drop to travel up and down.using drop sensor u can make it stable.but how to change its travel direction?

 

[student1616]

and u shld use 5v for whole circuit.its much better than using killer 12v near PIC.

 

[atntias]

well first thx for ur answer il give it a shot like u said... about the 12V i dont really have a choise beacuse my leds rquire 12V and using 2 power supplies is ok for testings but not for my fountian....

as for what u asked it very simple if the droping rate match the blinking rate or is a multiple of it, as u know it will freeze seem to freeze, when u want to show an effect that is moving down at a certin speed, u have to increase or deacrse the delay for each drop.
here the concept is explained here very well...
http://www.eccentricgenius.com/wp/2006/08/10/stopping-time-visually/

 

[j.p.bill]

I made a drop detector that used two pairs of IR emitters/detectors arranged at right angles across a cylinder about 300 mm across. Got a good signal whenever a drop passed, plus no problem with electrodes getting corroded/coated.

 

[atntias]

any chance for circuit schems?

 

[student1616]

so using the drop sensor we can make the drop stable and by varying delay time one can make the effects right.
can u share the code and complete circuit with us?
and use the PCB mounting terminals.they are gold plated and won't corrode so easily.
**broken link removed**

 

[j.p.bill]

Be patient. I did this before I had the use of a CAD program, so the files are non-existent. And I'm going to have to return the computer for a warranty repair.

Basically, though, the IR emitters had 50 ma current through them, and the detectors (phototransistors) had somewhere from 56K to 82K collector resistors, running on 5 volts. I drilled axial holes in scrap aluminium to mount the devices. The scrap was thick enough to collimate the optical path - handy to shield stray sources and you can pass a rod through the holes to allign the mounts before fixing them in place.

I think the signal from the phototransistor went to a comparator, with a small positive bias on the - input. I used two of them because the project needed to see if the drop was on a path exactly into a vial of soil used to measure mechanical errosion from raindrop splash.

 

[atntias]

that sound very interesting J.P, im currently using a different drop sensor
its in this post on the first page, take a look. its working great but it would be nice too to have the electrodes touching the water.

it works like u said student1616, i found out the problem was i was working under voltage prboebly the solder shorted the transistor causing the pic the
burn. that finsihes the circuit for me il post the cicuit here but the pic code is just getting started im using asmbler if any1 wannt to help id epraciete beacuse it the first real programming pic for me,thou i have a fraind i can call for problems wich is nice.
when il be done il probbly post everything here