The variable resistor HERE

The 1K Resistor HERE This is the 1 I have extra of, to help stop the problem with the variable resistor.

 

Is this the IC socket I would need?

Here

 

Pretty close. There is a kind in between, that has the leads but machine pins. This part has the pins but not the leads...

http://www.rapidonline.com/Cables-C...s/Surface-mount-IC-sockets/63769/kw/ic+socket

As near as I can tell this company doesn't carry them.

 

I assume the leads are to stop the IC getting hot when soldering due to the heat transfer??

 

I assume the leads are to stop the IC getting hot when soldering due to the heat transfer??

Partly, but it is there because the 555 is most likely to blow if make a mistake. It is hard (and distructive) to unsolder 8 leads and then resolder them, a socket eliminates that.

OK, latest revision...

Pay special attention to the wires around R9, they also transfer the + power supply lead to the other side.

 

Bill,

I replaced the link @ E4 with a 1K resistor, still the variable resistor has to be turned up full for the unit to function correctly!

Any Idea's? Could it be down to the power supply not being big enough millamperage wise??

 

I definatly think it's a problem with the Variable resistor, any other position apart from full open (Fully turnd to the left) does not work.

I have another variable resistor I could try, but I done that before I changed the link to the 1K resistor and it worked exactly the same as the 1st.

What could it be Bill??

 

Double check your wiring. The lead on the top of the pot is the center wiper. With these small pots you can see the innards, including the wiper. Make sure it is in the middle. On my print it is D3.

Also double check your wiring around that area. Some of those wires are doing double duty, transfering the power supply to the other side strips as well as connecting to the pot.

If you have a camera this would be a good time to take pictures.

Something else just occurred, those small pot leads don't fit well in the holes, make sure R9 is well seated in the sockets.

 

I am away to check connections and get the camera out.

Hopefully wont be long.

 

Bill,

I seem to have sorted it out. I think it was a bad connection between E28 to E30.

Do you think this would have caused the problem??

I put the parts back I removed and checked that connection for some reason and it seems to have fixed it.

Green LED stays constant bright green, even when pot is turned all the way down, alarm state time is reduced with the turning of the pot aswell.

So all in all, I think it's working.

Is that extra resistor still required? or was that to try and correct the problem that I created.

I will get the pump connected and test the unit with the pump running, hopefully it should have no issues now that the circuitry is working.

I am so happy that it's working and might have guessed the problem was my doing.

Just to check, I think I could fit this on a 29 row board (like this)

By moving (J3 to J4) (G2 to G4) (F2 to F4) (E2 to E4) (E4 to E5) (A3 to A4) (A5 to A6) (A6 to A7) (D5 to D7) and R9 to colum 3,5 and wiper on 4. what do you think? Will this cause the illusive smoke.

I hope that is not to confusing, but if I do that I can fit it on the smaller board above, I can't find a slightly bigger protoboard than the 29 rows, ie 32 rows.

You have been a great help on this Bill, even though you are 1000's of miles away, gotta love the internet.

 

Yep, some re-laying out required, but that board will work just fine. I suspect your C5 is much smaller than mine, which makes it possible.

When you get it finished maybe we can post it in the completed projects forum as a joint project.

So, think you'll do something like this again?

You're not really through though, until you use a full power supply and the pump. The sonalert we know works (and works, and works).

So what did the missus think of all the fuss?

I'd leave R10, there is a real problem that requires it to be there. I'll start including something like that from now on in my drawings. If the pot is dialed to 0Ω it is possible to blow the 555 (or 556 in this case).

 

I am sure I will build something again, not suer what tho, and it may be a while before I go solo.

The wife don't get these things!!!

I have the power supply and pump on another system I built, I will remove them and test the system again, it is much more basic than this 1 tho.

I will leave R10 alone then.

 

Hey Bill,

I was thinking about the possibilty of maybe upgrading the float to an optical sensor!!

Mainly for relability, is there alot to change in the design of the wiring circuitry.

See HERE for Optical Sensor details.

 

I was also thinking about a on/off switch, as when it is in alarm state, the only way to get it to reset at the moment is by moving the float, this maybe inacceasible, when installed, so an on/off switch would help reset the system, save having to go find the socket and turn switch it off at the wall.

 

We've gone full circle, see post #2.

They may be a direct drop in (which appears likely), or it may require another transistor similar to Q2 to interface.

I don't know how much cleanliness is an issue in these tanks. The optical sensor is very rugged, but it will need to be cleaned occasionally. Other than that it was my first recommendation.

At this point you need to switch over to better power supply, something regulated and high current.

Power switches are easy, just add on in the box you build. I figured you will have a chassis, something that will ultimately mount the LEDs, the power switch, and any connectors you use for the power supply, pump, and sensor. Simple toggle switches are cheap too. Do you have a label maker? It would come in handy for this.

 

Sorry about taking you full circle Bill, I never mean't too.

Introducing contaminants is not recommended in a tank.

This is all a big learning curve for me and I am adjusting as I go, also the Optical sensor is way more sensitive and precisce.

I am going to look up a power supply, what amperage do you recommend??

I have a labelling machine.

 

I have found a 12v DC regulated supply rated at 2amps, is this big enough?

It is used for powering CCTV camera's.

HERE

 

Depends on your pump. The rest of the circuitry is trivial, around 0.1A (actually less). The pump is your main current draw, you might take the time to measure it. Also, think about putting a fuse in the chassis, if the pump freezes it can draw a lot more current.

 

Hi Bill,

I will hopefully get the pump measured for current draw this weekemd and the proper power supply.

I will post the results this weekend.

 

I am looking forward to it.