My e-caller on the cheap.

Or, a work in progress!

By Bob Zettler

February 15, 2014

Just wanted to summarize my build tonight and share with others.

I wanted to build an inexpensive, yet functional and dependable e-caller to serve as a secondary system AND a backup just in case...

Saw several others and copied some of their design but added a few simple touches that I hope will serve me this season. Right now it's almost complete, I just need to weatherproof it and put a plate on the outside – I had one but it was the wrong type.

I started with the AMP which I got on sale at Amazon a few months back. I already had many of the basic components: 12-volt batteries, nuts, washers, bolts, terminal (electrical) connectors, and extra wire. I then needed something to hold it all together, two PA Horns and speaker wire. I was lucky that I saw a sale on speaker wire from Radio Shack a few months ago, and I got 500' for around $20, but you can usually find 100' spools for around $10 at Wal-Mart (on-line) and Amazon. Also, this past week Sears had a 12” plastic tool box on sale for $5 and they had given me $8 is ShopYourWay Rewards points so I got it for free!

That left the PA Horns. I had a Pyle 65W left over from last year still in the box that I had bought (again) from Amazon for around $17 but its now around $25 - if you can find one. Right now and until I get another one, I got a PowerHorn from Radio Shack (40-1445). It sells for $39.99 right now in-store, they are out on-line, but there is another deal going on right now. If you take in five electrical items (like video games, old cell phones, or the like) and they will give you $5 each up to $25 maximum credit so I got one of those for $15 plus tax on $40.

PARTS

AMAZON

LP-2020A+ Lepai Tripath Class-T Hi-Fi Audio Mini Amplifier with Power Supply - $18

Pyle PHSP4 6-Inch Indoor / Outdoor 50 Watts PA Horn Speaker - $15/each

Coleman 10-Inch Steel Tent Stakes (4 pack) - $4

Belkin Audio Y Cable Splitter 1-Mini Plug, 2-RCA Plugs (6 feet - RCA to 3.5MM plug) - $5

12V 7.2Ah SLA Rechargeable Battery for Security Systems/ Replaces Standard 7.0Ah - $18

SEARS

Craftsman 14” plastic toolbox ($10 but I got it free)

MENARDS

Common electrical outlet - $1.30

Common electrical outlet cover plate - $1

Cord Wrap for Indoor/Outdoor Use 150' 16/3 Cord Capacity - $1

ASSORTED PARTS (on hand)

1/8” wide, 1” long bolts with related nuts and washers

16-gauge speaker wire (previously purchased 30' spools for CHEAP)

TOOLS NEEDED

screwdrivers

soldering gun/iron with electrical solder and flux

Dremel tool with cutter blade

voltmeter

Magic Marker

electrical wire stripper/crimper

electrical tape

liquid electrical tape (optional)

I started by figuring out where to place the AMP on the inside of the tool box and decided on the inside-center of the lid (I tossed the tray inside). Then I drilled the four holes to hold it in place and used four bolts with large washers (to add sturdiness) between the bolt head and the top of the tool box and then a washer and a bolt on the bottom to hold the AMP firmly against the top inside of the toolbox lid. I did this also because it allowed plenty of room to place two 12-volt batteries inside and for the cables and the rest.

I decided to try out the simple electrical outlets instead of speaker plugs and jacks. This saves costs and it is simple to plug in the field. All outlets and plugs have a large blade and a smaller blade so I was then careful to wire everything the same way. Remember that it's red to red and black to black, or it's positive to positive and negative to negative. THIS CAN BE IMPORTANT to make sure you match everything to keep polarity the same.

I did try everything out in advance just to make sure I was on the right track.

Then I took the outlet and placed it against the outside of the back wall of the toolbox and marked it with a marker to then use my Dremel to cut out an opening. I cut just enough for it to fit and then with it in place, I drilled the four holes to bolt it in place. After using the four bolts and nuts, with large washers on both ends to ensure sturdiness, I tried to attach the cover plate only to discover I bought the wrong one. I will put the right one on tomorrow. Then using some excess speaker wire, about a foot long (two-pieces), I stripped the ends and attached to the outlet (REMEMBER to ensure the same polarities), tightening them as good as I could, and plugged the other ends into their respective points on the AMP (REMEMBER to ensure same polarities).

Then I wrapped the wire ends to the speakers, making sure which was the positive and negative ends, and soldered them to ensure strength. I coated these couplings with liquid tape and then after it dried, wrapped them in real electrical tape.

Then, I attached the other end of the 50' of wire to an electrical plug. This was probably the hardest part trying to get the blades back into place but I persevered. Again, I matched the plug blade ends to their respective (my choice) wire ends. This is easy as the plugs AND outlets can only be plugged together one way as one blade is wider that the other and the plug has one opening larger than the other. Once completed you can wrap the wire around the Cord Wrap, or, if you attach the stakes to the speakers, I believe you can fashion a Cord Wrap there which would make it easier to transport and wrap up!

This AMP uses a 12-volt electrical plug in from a 110-volt outlet converter. I simply cut the cable (while it was unplugged), then stripped the wire ends from the outlet end where the I plugged the converter back in, and using the voltmeter I was able to determine which was positive and negative. With the other end, I stripped the cut end of the cable (making sure which was positive and negative) using the electrical wire stripper/crimper and crimped the ends to the terminal (electrical) connectors – one red (positive) and one blue (negative) which connect to the 12-volt battery. These are the same batteries you can buy at most any battery store but I had two from a backup UPS and am using them to save costs. Most any rechargeable batteries should work and if this one proves to be an issue, I will try running two of them in parallel to last longer and have enough juice to do so, or, will use an ATV/motorcycle/marine/battery.

That leaves me with figuring out how to hold the battery in place. For the time being, I am whooped tonight, I will just wedge in some Styrofoam to keep the batteries from sliding! I am also going to waterproof/resistant the box at the outlet, and where I placed the AMP, with silicone. No, it wont guarantee it but it should hinder any moisture from seeping in!

The last piece just plugs into the AMP. The RCA plugs go in here and the other end, a 3.5MM jack, can be plugged into a Cell phone, MP3 player or the like. Attached the wires to the battery, plug the speakers into the outlet, and start the music....I mean Snow goose sounds and adjust the volume, Bass and Treble to the birds liking!