matthewY Posted February 2, 2010 Report Share Posted February 2, 2010 The $2 shop tank overflow alarm: K, title is a bit misleading as it does cost a bit more the $2 to build the unit, however, the main part is only $2 :-) Approx total cost, $10 - $15 Tools required: Small screw driver, Wire stripper craft knife Soldering iron + solder Drill (5.5mm - 6mm drill bit) Parts required: Resistor, 10K ohms - 30Kohms (dick smith, approx 30 cents per 5 pack) Float switch (ebay: Liquid Level Float Switch, approx $5 usd inc p&p) 3.5mm socket (dick smith part number P1240, approx $2 nzd) 3.MM plug (or an old headset / mono / stereo cable that you can cut up) $2 shop door alarm Start of by picking up one of the $2 shop door alarm as pictured below. I've seen other types available and haven’t opened to see how similar they are so if you can, go for the type pictured.... Remove the battery cover and unscrew The circuit board has some soldered on reed switches, unsolder them and remove. Trim down the part of the circuit board where one of the reed connections were. My one had a slit and I cut just after that slit, I prob could have cut on the slit and would end up with a better fit when I added the socket (later step). Flip the board over and using a craft knife, scratch through the green coated part of the circuit board around the area you just cut to expose the copper underneath. Add a small (real small) bit of solder to tint the copper. You want to avoid a thick layer of solder protruding out (my picture shows I put way too much on and I had to clean it off afterwards....). Quote Link to comment Share on other sites More sharing options...
matthewY Posted February 2, 2010 Author Report Share Posted February 2, 2010 Grab the 3.5mm socket and wedge it between the circuit board such that the big long connection sticking out (theres 3 but you want the bigger one of the 3) is on the underside (green side) of the circuit board and the other 2 connections are on the brown top side and solder the bigger connection to the exposed part of the circuit board you created above. Unsolder the power connection (negative one from memory, but its highlighted in picture above) and connect it to the "inner" leg of the 3.5mm socket on the other end of the board (picture below)... Note how above I said I cut the circuit board too short? well because I did, I had to make a gap between the socket and the circuit board. if you estimate better, you shouldn’t need such a big gap when putting it all together Unsolder the speaker cable from the "left" leg of the black inductor/transformer thing. Hook up the resistor (10Kohm = loud but not ear bleeding, 15 - 20Kohm = good noise level which prob wont scare fish and you can still hear from the room next door, 30Kohm is like pretty soft) to the leg and the loose cable. Note the Lshape I cut it down to and how I position them (fits better and less chance of a short?). Put the top part of the case together with the circuit board hanging out a bit and drill a hole just before the centre line on the right top of the case. The picture I took shows that I drilled it way to high, it should be further down below the center line (use the picture a few places down as a reference of where it should be) Quote Link to comment Share on other sites More sharing options...
matthewY Posted February 2, 2010 Author Report Share Posted February 2, 2010 Put everything back together and close the unit up and screw it all back.... If you drilled in the right spot (not like me) and you cut the board in the right spot (also not like me), everything should fit perfectly. If you did a few mistakes along the way, you will find they don’t fit as well as you would like and you may have to re-solder or re-drill to make it right. Joining the float switch There’s a few different ways to go about this, I simply grabbed a mono sound / computer cable I had around which I would never use again but the other way would be to grab a broken set of head phones or go to dick smith and grab a 3.5cm mono plug. Pictures / instructions below are based on what I did….. Grab the cable and cut the end off (or cut half way down if you want to reuse the end). If you have heatshrink tubing around then cut that to the size of approx 5cm and feed through the cable. If not, skip this step and use tape later…. Quote Link to comment Share on other sites More sharing options...
matthewY Posted February 2, 2010 Author Report Share Posted February 2, 2010 Strip the 2 parts of the cable, twist, tint (lace with solder) and cut to shape below such that the outer part is much shorter then the inner part and the inner part is exposed only by a small part at the top. This is to avoid any chance of a short circuit…. Do the same with the float switch cable end (strip, tint, cut into same shape)…. Now solder the float switch cables together with the mono sound cable such that the long end of one cable is joined with the short end of the other cable… Notice that if we do the shape right, there should be no chance of a short…. K, if you used heat shrink, move it down to cover the exposed joints and lightly heat the heatshrink with a lighter. If you didn’t use heatshrink, grab some tape and tape up the exposed cable. You can tape the 2 individual cables first and then tape over them both to help avoid short circuit. So all done and ready for testing…. Turn the switch on from the side of the alarm and hang the cable into the tank…. Quote Link to comment Share on other sites More sharing options...
livingart Posted February 2, 2010 Report Share Posted February 2, 2010 nice one, very easy to follow Quote Link to comment Share on other sites More sharing options...
A-town... Posted February 2, 2010 Report Share Posted February 2, 2010 Awesome thread. will have to try for myself Quote Link to comment Share on other sites More sharing options...
HaNs Posted February 2, 2010 Report Share Posted February 2, 2010 Respect Quote Link to comment Share on other sites More sharing options...
Brennos Posted February 2, 2010 Report Share Posted February 2, 2010 Excellent. I love diy threads. Quote Link to comment Share on other sites More sharing options...
matthewY Posted February 2, 2010 Author Report Share Posted February 2, 2010 :-) solves my overflow problem Quote Link to comment Share on other sites More sharing options...
Ira Posted February 2, 2010 Report Share Posted February 2, 2010 So, is the plan to install this when you're filling the tank up so you don't overfill it? Quote Link to comment Share on other sites More sharing options...
matthewY Posted February 2, 2010 Author Report Share Posted February 2, 2010 Yep, pretty much. I hang mine into the tank and leave it there. after draining the water, i switch it on and start fulling from the tap (I do add prime before fulling :-) ). I full my tank pretty slowly, maybe 20L in an hour... had in the past overfulled it and not know cos been destracted watching tv or whatever.... Once it goes of, turn the tap off and switch the unit off, no need to remove it.... Can think of other uses too (can work in reverse to indicate too low water level etc) but this one works well in my situation.... Quote Link to comment Share on other sites More sharing options...
Cricketman Posted February 2, 2010 Report Share Posted February 2, 2010 For people speaking english: Replace "Full"/"fulling" above with "Fill" and "Filling" And good job btw too. Nice to see some good DIY skills. Quote Link to comment Share on other sites More sharing options...
Insect Direct Posted February 2, 2010 Report Share Posted February 2, 2010 thats awesome Quote Link to comment Share on other sites More sharing options...
matthewY Posted February 2, 2010 Author Report Share Posted February 2, 2010 Replace "Full"/"fulling" above with "Fill" and "Filling" English and me never really go on well...... He no longer talks to me Quote Link to comment Share on other sites More sharing options...
Ira Posted February 2, 2010 Report Share Posted February 2, 2010 English and me never really go on well...... He no longer talks to me That would be "English and I..." Hehehe. Quote Link to comment Share on other sites More sharing options...
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