Just did all the wirering for my CSI, no problems there... I used this popular install page :

http://ken.lowrance.com/projects/CSI...mp/default.htm

And decided to do both the switch and the warning light

My question is, what the hell is this light for?? it does NOT tell you if the pump is dead, does NOT tell you if the wirering went bad ...etc...

It only shows if the wires that got to the light actully work

Any one got a simply way to fix this and actully make the light tell you when there is no current flowing???

Thanks


*EDIT*
heres and Idea... Right now i just spiced a wire into the power wire to the pump. this wire lead to the light inside the car and then just grounded inside.
What if i broght the ground from the light and spice it into the GROUND for the pump. would that work?

 

This light only tells you when you have voltage available to the motor. It is not an indication that current is flowing through the motor. A current monitoring indicator is a little harder to implement but it will tell you if your motor windings have opened.

If you have a little electronics background you could build a current monitoring circuit I designed that has an LED operate indicator and generates an audible alarm when current is not flowing through your pump.

Current monitor page

 

I'm not very good with schematics, but can you give a brief explanation of how your current sensing circuit schematic works? Those are transistors it looks like? This is monitoring amperage?

 

Wow, where was 94sleeper when we were discussing this last week HeadFL?

http://web.camaross.com/forums/showt...hreadid=147823

http://www.personal.psu.edu/users/b/...isc/CSIrev.bmp

There is the schematic i was working on. It looks like the Pump draws a good deal more amperage then i was planning.

I think i'll just use 94 sleepers since he's got all the details worked out.

94sleeper, out of curiousity would my concept have worked assuming i would have sized all the resistors ect correctly?

 

I was thinking the same thing actually.

I do believe your concept would've worked though.

 

Ok, i am also not following this schematic to full understanding. Could you walk us through it with a little more detail.

TIA
-brent

 

OK

This circuit monitors the current draw through the motor by using a low resistance shunt resistor to sense the current. When the 5.8-6 amps flows through the .06 ohm shunt resistor you will drop between 350-360 mV. This sense voltage is routed to the + input of the LM393 comparitor. The negative input to the comparitor is fixed by voltage divider setup with the 100 and 5.6k resistors. This fixes the negative input of the comparitor at about 230 mV.

Whenever the comparitors positive input voltage is greater than the negative input voltage to the output (pin 1) is 12 volts. Whenever the negative input is greater the comparitor output is 0. In this circuit whenever the sense voltage is greater than 230 mV or 4 amps you get a high out of the comparitor. When the current drops below 4 amps you get a low out of the comparitor.

When the comparitor output is 12 volts both transistors are biased on which causes the LED to illuminate and the buzzer to be silent. When 0 volts is seen at the output of the both transistors are biased off which extinguishes the LED and sounds the audible alarm.

I currently have this circuit installed and it is working very well. I had considered putting a kit together but I would need to have some interest. I would guess the alarm kits would run around 30 bucks. It will likely cost you about 20 bucks to put one together yourself.

Hope this helps.

 

What does shunt resistor mean? Is shunt just an adjective meaning it's a small resistor creating a small voltage accross it, or is it somehow manufactured different?

Is the comparitor just a mosfet transducer like in my circut except that it compares it to any reference voltage you provide via the voltage divider instead of the transducer just acting like a valve opening at an established point. I guess what i'm asking is the comaritor just a slightly more versatile transducer because you can vary when it turns on without swapping on a whole new one?

Your 13.5V would need to be attached to a relay like #87 on my diagram, correct? By the way i'm not trying to take credit for the diagram i plaugerized/basterdized from Ken Lowerance, it was just easier to modify his.

 

A shunt resistor is an adjective applied to very low value resistors which act as current sensors. Typical shunt resistors have very high power ratings for their resistive value.
This is somewhat of an oversimplification but in this application yes. FETs and other transistor types are primarily amplifiers of small signals. They are also non-linear around the bias point. In this application you are using it as a switch so it acts alot like the comparotor. The advantage of the comparitor is the ability to uses low voltage inputs and the bianary output (high or low).
You would want your current monitoring circuit wired to the switched 12 volts inside your car. That way if power was ever lost to the pump relay your current monitor could tell you. The shunt resistor sense voltage and the current monitoring circuit are both referenced to a common ground.

 

Right, so you want the pump and the 5.6k resistor wired into the relay and the comparator terminal #8 and everything else to the right of it on a seperate switched supply. Like the feed to the relay(if that would carry enough current) or anywhere else switched.

That really just keeps the buzzer functional though since the LED is an 'OK/GO' indicator so that would go out if it lost power and you had it all off the same fused relay. Of course if your going to go through all of this you want your buzzer to work in all cases.

Very nice setup 94sleeper

 

Lotta good info in this thread for searchers to find

 

I am using 94Sleeper's warning circuit on my car and love it!

 

Whats the best place to buy these parts?

 

The only thing off of the relay switched output should be the pump. The 5.6k resistor should really be hooked up to the same switched power as the rest of the monitoring circuit. The 5.6 and 100 ohm resistors are just a voltage divider to fix the comparitor threshold.

If the 5.6 ohm resistor was connected to the relay and somehow you lost power at that point both of the comparitor inputs would be at ground and that is an unknown state for a comparitor.

I will try to put a kit together and place all of the components except the LED and Shunt resistor on a PC Board so it can be easily installed.

 

I purchased most of my components from Jameco Electronics. If you do a search you will find them on-line. The Shunt resistor was harder to find I had to order it from a local electronics supply house.

Again I plan on putting together a kit and I should have a few made up within a month or so.