Fish-finder/Echo-sounder

Gadgetman

I know·the theory of how·these things work as I've been around boats since I was a toddler, but have never found any good schematics for them.

Does anyone know of any schematics which could be adapted for use with a BS2p and a row of leds to indicate how deep the water is?

It would be quite nice to have something like this in my cayak, particularly if I could get a decent short-range resolution.
(I particulary want to know when I have depths less than 4feet under me as a capsize in such shallow depths can be quite dangerous... )

·

DntGvaSht

While this link is intended for air propogation (~1200 feet per second), you could also use it for water just use different timing.· http://www.leang.com/robotics/info/articles/minison/minison.html

It's already setup to interface with a microcontroller.· The stamp programming should be pretty straight-forward, something like:·

tim VAR word
dist VAR byte
main:
   PULSOUT 0,1         'send pulse
   PULSIN 1,1,tim      'wait for echo pulse
   dist=(1200000/tim)  'measure distance in X units
   BRANCH dist lit1,lit2,lit3,lit4,lit5'light appropriate LED
GOTO main              'Reading out of range, keep measuring
lit1:             'LEDs 1,2,3,4,5 will light for high warning
   GOSUB rst
   HIGH2
   HIGH3
   HIGH4
   HIGH5
   HIGH6
GOTO main
lit2:             'LEDs 1,2,3,4 will light, etc etc
   GOSUB rst
   HIGH2
   HIGH3
   HIGH4
   HIGH5
   GOTO main
lit3:
   GOSUB rst
   HIGH2
   HIGH3
   HIGH4
   GOTO main
lit4:
   GOSUB rst
   HIGH2
   HIGH3
GOTO main
lit5:
   GOSUB rst
   HIGH2      'only 1 LED lights, indicating some obsticle.
   FREQOUT 7,1000,1000 'Optional alarm buzzer sounds
   GOTO main
rst:
LOW2:LOW3:LOW4:LOW5:LOW6       'set all LEDs off
RETURN

Hope this helps

p.s. a feedback loop (with RC circuit)·would be required from pin 0 to 1 to allow the PULSIN to trigger properly.

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Gadgetman

Hm....

I've looked it over, and the electronics doesn't look too weird.

Most commercial fish-finders allows you to place the transducer on the inside of the hull if it's plastic or fibreglass, as long as you use epoxy and make certain there's no air bubbles trapped in the glue.

I'll try to track down the components and see what kind of abuse they can take...