The home made e-caller

[SD Handgunner]

Since there is some interest in building an Electronic Caller I figured I'd post this here. 
 
At any rate most of the items can be purchased through your local Radio Shack. If you go to Radio Shack' web site you can see if your local Radio Shack has the items needed in stock. 
 
To start with you'll need an Amp. I have found the little Radio Shack Amp (part #277-1008) to provide better sound and volume that you'd think possible with this small amp. I have experimented with this and other amps and dollar for dollar this little amp works, provides all the needed volume for about 90% of the calling you'll ever need, and the 9 Volt transistor Battery seems to last forever (provided it is not left on when not in use for days on end).   
 
This little Radio Shack Amp actually is in a small plastic housing and there is a little 2" speaker inside the housing. The first thing I do is to remove the amp circuit board from the original housing. Next (through trial and error) I find the sweet spot on the volume control (on off switch volume control) at which the volume does not get any louder by turning the volume past that point, but rather just increases amp hiss/noise. I then remove the volume wheel from the volume control and hot glue the volume control in a fixed position.   
 
Since we have disabled the On-Off Switch on the amp, we need to wire in a separate On-Off Switch (Radio Shack #275-1565). I also like to wire in a small LED Indicator Light to help in not leaving the Amp turned on when not in use (Radio Shack #276-084). 

The wiring seems to confuse a lot of people but it is fairly simple. To start with cut the 9 Volt Battery Connector off of the Amp Circuit Board. I cut the battery connector off as close to the battery connector as possible so I don't have to add any wire to the Amp Circuit Board.

We need to connect the Positive RED lead from the Amp Circuit Board and the positive RED lead from the LED Indicator Light to one side of our On-Off Switch.

The positive RED lead from the new 9Volt Battery Connector (Radio Shack #270-325 for a pck of 5) gets wired to the other terminal of the On Off Switch. The negative wires from the new Battery Connector, Amp Circuit Board and LED Indicator Light all get soldered together. 
 
That is about it for wiring. Depending on how or what you choose to mount your amp in (I use either a Radio Shack Project Enclosure #270-1805 or an insulated Coffee Mug) you may or may not need a couple of 90 degree adaptors (Radio Shack #274-372). The 90 Degree Adaptors are needed for clearance to get the speaker wire and patch cord (that goes between the amp and the sound source) plugged in inside of the coffee mug.     
 
Next is the patch cord to go between the Amp and the Sound Source (Radio Shack #42-2497 1' patch cord with 1/8" Stereo Plugs on each end) and the sound source. You can get a premade 6' patch cord also if you need to have the sound source farther away from the amp.   
 
The speaker I have found to produce the absolute BEST sound is the Speco SPC-5 PA Speaker. These can be order online from Lashen Electronics. This speaker comes with about 10 feet of speaker wire and a plug attached (or at least the ones I have used have) to plug the speaker directly into the Speaker Jack on the Radio Shack Mini Amp.
 
On to the sound source. Your imagination and what you are willing to spend will limit your choices. Some of the guys are using some of the new I-Pods, while others are using MP3 Players and yet others digital voice recorders. I have had good luck with the Rio 600 MP3 Players, and if I had a complaint it is the small buttons and small readout screen (I can not read the track titles without my glasses). However I have also used Portable CD Players and Walkman Type Cassette Players too for the sound source.   
 
Radio Shack Parts List
 
Radio Shack #277-1008, Mini Audio Amplifier/Speaker
 
Radio Shack #275-1565, SPST Soft Feel Push on Push Off Switch
 
Radio Shack #276-084, LED Indicator Light for Amp (fits 3/16" hole)
 
Radio Shack #42-2387, 6 Foot Patch Cord 1/8" Stereo Plug on each end
 
Radio Shack #270-325, 9V Snap Type Battery Connectors (Pkg. of 5)
 
Radio Shack #270-1805, Project Enclosure (6”x3’X2”)

This photo shows the amp circuit board inside of the project enclosure. You can also see the on-off switch and the indicator light.



As can be seen I had to cut away a small corner of the amp to get it to fit inside of the project enclosure. I used a cut off wheel on a dremel tool to cut the circuit board to fit.

One of the harder things (never could read a tape measure) was to get the holes for the Input Jack and Speaker Jack that are part of the amp ciircuit board to protrude through the outside of the project enclosure so the Speaker and Sound Source can be plugged into the amp.



I used a plastic cell phone holder that I modified to hold the Rio 600 MP3 Player to the top of the Project Enclosure. This produced a compact caller that can actually be carried quite easily. Simply place the speaker where you want it, plug it in to the amp and start playing the Coyote Gettin Blues.

Larry

[SD Handgunner]

Part 2



Shows a side view of the Coffe Mug Caller with the Rio MP3 Player attached at an angle to the rear of the handle. At the front portion of the coffee mug I attached a small piece of plastic to serve as a foot to set the coffee mug on when in use so it doesn't tip over. You can also see that the speaker is mounted flush with the front edge of the coffee mug (I cut off bottom rounded portion of the coffee mug to mount the speaker into).



This is the business end of the coffee mug caller, and hopefully the last thing Wiley Ole Coyote ever sees.



Due to how I mounted the speaker inside of the coffee mug I had to use the 90 degree angle connectors to plug in the speaker and sound source so I still had enough room to get the lid on the coffee mug. I used a single self tapping screw to secure the amp to the inside of the coffee mug. To seal up the lid I removed the inner portion and cut a 3" round piece of solid plastic and attached it to the lid.

Depending on what you choose to mount everything in, you may or may not come up with a better idea.

While I have not done it YET, an Azden WLX-PRO Transmitter and Receiver (originally intended for a remote microphone for a cam corder) will work to serve in making the caller remote. The Receiver would get mounted inside of the coffee mug and the cord from the amp to the sound source would get plugged into the Azden Receiver. A small hole would be needed to extend the Azden's Antenna out through the top of the coffee mug. While I have not measured it (don't have an Azden WLX-PRO yet) I think there would be room inside of the coffee mug for the Azden Receiver along side of the amp.

The Azden Transmitter would them be connected to the Sound Source via a 6' patch cord. The 6' patch cord is important as that is the antenna for the transmitter. A person could then keep the Azden Transmitter in one pocket and the Sound Source in another pocket.

We have tested the Azden WLX-PRO up to over two city blocks before the sound started cutting out. To me that is about as far as you'd ever need the speaker away from the caller.

Larry

[SD Handgunner]

Part 3

This Amp (CanaKit UK-193)  from www.canakit.com is a 12 VDC Amp that is rated for 16 Watts of RMS Power 4 ohms (12 Watts RMS Power at 8 ohms). Power supply is listed as 12 VDC to 18 VDC at 2A.

For the Battery I went with a #SLA1035 I picked up at Interstate Batteries. This is a 12 VDC Sealed Lead Acid Battery rated at 3.2 Ah capacity.

I put the amp and battery inside of a Radio Shack #270-1807 (5"x7"x3") project enclosure. Other items I needed to put this project together are a Radio Shack #275-1565 On-Off Switch, Radio Shack #276-084 Red LED Indicator Light, Radio Shack #274-251 Panel Mount 1/8" 2 Conductor Jacks, and a Radio Shack #42-2387 6' Shielded Patch Cable (with 1/8" Stereo Plugs on each end to go between the amp and the MP3 Player).



To wire this up there are 6 posts on the Amp Circuit Board that have to have wires soldered onto them. Two are for the DC Power (+ & -), two are for the Speaker (+ & -) and two are for the Input (MP3 Player) (+ & -). As can be seen (I think) The amp is mounted in the project box via a screw in the upper left corner that goes into a threaded standoff in the box, and the volume control. I also made a little bracket that I attached to the project box that fits on top of the battery to keep in in its position if the box should get turned over.



On the outside of the box the on-off switch is to the left of the volume control, with the indicator light above the volume control. Above the on-off switch are the jacks for the Speaker and Input (MP3 Player).

All in all there are 12 solder joints that have to be made to put this together. The wiring is quite simple, the power and ground wires get soldered onto the Amp Circuit Board. The Power Wire gets connected to one side of the switch (along with the power wire from the LED Indicator Light). The other side of the switch gets wired to the battery positive side. The Ground (or negative) wire from the amp circuit board gets connected to the ground wire from the LED Indicator Light, and then tied to a ground wire that gets connected to the negative terminal on the battery. That is all quite simple.

The positive and negative wires from the Speaker and Input posts on the circuit board get wired to the respective 1/8" Jacks.



Yep that is really all that is to it. This new Amp probably has more volume than I will want or need MOST OF THE TIME, but should be able to reach out there on those windy days, and or for long distance howling to locate Coyotes.

Larry

PS I haven't wired in a Charging Jack for the Battery as yet since the parts I bought were not the right size for what I needed. I think I am just going to wire in a Cigarette Lighter Plug in for the Charging Jack, but forgot to pick one up. This will go in the upper left hand corner of the project box above the Volume Control and Indicator Light.

[Cottonwood]

Now this is a great step by step post on how to do it.


Thank You !

[SD Handgunner]

Thank you.

The one I currently use is the one in the 3rd post with the 12 VDC Cana Kit Amp.

I am sure there are better MP3 Players available than the RIO 600 I am using but I picked up a bunch of these off of E Bay cheap.

I have always been going to add an Azden WLX-PRO Wireless Remote to mine but have never done it. I think that would make it a little more versatile at times.

Larry

[mrbigtexan]

how much would you sell one of these for?

[SD Handgunner]

Sorry but I am not really interested in making these callers and selling them. I really don't have the spare time to put into acquiring all the parts and putting them together with my work load currently. Besides the closest Radio Shack to me, that carries all of the parts needed is 70 + miles away.

Besides these are really quite simple to put together and only your imagination limits how you decide to build one. Heck if I can put one together I am thinking just about anyone can.

I meerly posted this as there has been some discussion on building these types of E-Callers and it is my way of helping out fellow forum members should they decide to build their own caller, just to show them a couple different ways they can be put together.

Larry