Instructables

Step 1: Parts

Picture of Parts
PARTS LIST:

IC1: 4001 CMOS 2 input quad NOR gate (14 pins)
D1: Red LED
D2: Green LED
R1: 22 K resistor
R2, R3: 200 ohm resistor
R4: 100 ohm resistor
R5: 200 K trimmer resistor

One 14 pin IC socket

Misc: copper or copper clad probe, 9v battery connector, 6 lengths of insulated wire, and a pc board, box (I used an empty SwingLine staple box).

NOTE: IF you use a section of copper for the probe rather then a copper CLAD board, you will need 2 of them, and a bit of insulation attached in between the two pieces.

Step 2: Assembly

Picture of Assembly
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I normally try to eyeball just where components will be on the pc board, and place the Socket in what I feel is the best position for it. Everything else can be soldered into place in the order most convenient for each person.

One caution: When inserting the IC into the socket, care must be taken not to bend any of the pins or misalign them. It is easy to put a 555 into a socket, since there are only 4 pins to a side, but with a 14 pin IC, there are 7 on each side and it can be a little more tricky.

Step 3: Completion

Once soldered into place, on can cut the holes needed for the LEDs and the push button switch into the top of the case, and install.

In this case, I am able to house the 9 v battery on the inside.
 
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NachoMahma5 years ago
. Good job. And prettier than the polarity tester. ;)
Goodhart (author)  NachoMahma5 years ago
Thanks, and yeah, I am thinking about putting a printed label on it for that final touch :-)
. We seem to have the same opinion of tools: As long as it works, who cares what it looks like. :)
Goodhart (author)  NachoMahma5 years ago
:-) Well, that was one reason for not spending a LOT of time looking for a box for the polarity tester. I have one that emits sound too (so you don't have to take your eyes off your work). I would have to dissect it and reverse engineer it, since I no longer have the schematic for it. The soil moisture tester requires adjusting, depending on the type of plant and the amount of dampness the soil is supposed to have. So, it works after a bit of tweaking. Do you think I should explain that it more detail?
> requires adjusting, depending on the type of plant ... Do you think I should explain that it more detail?
. Since this is in Home, then yes. You don't need a lot of detail. A few links to pages that will help the user determine the proper moisture. Point out that repeatable insertion depth is important. Will need to be re-calibrated as probe corrodes.
Goodhart (author)  NachoMahma5 years ago
Ok, thanks. I have touched it up a bit. Mostly in the last step.
Gjdj35 years ago
Sweet! Another project from Goodhart! This is great because I'm trying to grow a baby pine tree right now.
Goodhart (author)  Gjdj35 years ago
Thanks. Ok, just make sure you look up what it needs as for water, and then adjust the tester to optimal conditions.
gmoon5 years ago
That's cool. You've been a busy maker lately ;-).
Goodhart (author)  gmoon5 years ago
Thank you, I have been trying :-)
The last 3 days I have been a bit ill; not feeling real badly, but contagious nonetheless; so I have been confined to my quarters and well, that made for some MAKE time :-)
gmoon Goodhart5 years ago
That's the best kind of sickness--nobody wants to be around you, but you feel well enough to "play..."
Goodhart (author)  gmoon5 years ago
Yep, and, for once, I had the materials with me TO play :-)
gmjhowe5 years ago
Excellent work! i did not realise it was going to come out so soon. And.. Nice Box!! see how much a difference a box can make??
Goodhart (author)  gmjhowe5 years ago
Thanks, yes, we used the last staples from that box just as I finished making the moisture detector.....and no, I didn't secretly staple the parts together LOL