A Gizmo (or at least the HSA definition) is an electronic device that consists of a loudspeaker, an amplifier and some sort of music player. The device is used to play the sound of hounds 'in cry' i.e. when they're excited and chasing something. Any real hounds in the vicinity want to join in the fun and will head towards whoever is playing the gizmo.
Making a Standard HSA Gizmo
Making a Supersize Gizmo
When things don't work
Using the gizmo
Our standard gizmo got stolen out of our van, not by local hunters, but by local
kids one night who must have mistaken it for the next generation iPod or something.
I think a gizmo is a pretty useful piece of kit for any sab group (even after the
ban!) so I was keen to replace it. The first part of this article describes how to
build a basic HSA-
How to Build a Gizmo
The following table lists the parts (available from Maplin) you will need:
No. Component Maplin Code Cost £
10W 8ohm Horn Speaker 7.99 (XQ73Q)
12V 1.3Ah Battery 9.99 (MM22)
128MB MP3 Player 24.99 (L05BF)
Car Power Adaptor 8.99 (L17AR)
Car Power Extension Lead 2.99 (BV47)
Rocker Switch 1.99 (N50BW)
Aluminium Box 3.99 (LF16)
Before everyone gets up and starts shouting "That's way too expensive!" please bear
in mind the the two most expensive components are the MP3 player and the battery.
This is a very low spec MP3 player by modern standards so you may find somebody who
is upgrading to a better player and is prepared to donate their old one for nothing.
The rechargeable battery -
The basic wiring diagram for the setup is shown in figure 1. The aluminium box needs
a bit of work on it to fit all the components and switches -
While I had the drill out I thought it was a good idea to drill a hole in the MP3
player! I drilled a 4mm hole in the battery cover so I could solder wires onto the
battery terminals (figure 3). These power leads and the earphone leads (cut off the
earphones!) I threaded through into the case (figure 4) and bonded the MP3 player
to the back of the case using a 2-
All the wiring for this project came from the voltage converter which was the next
item I butchered! The purpose of this component is to convert the 12V supply from
the battery into 1.5V which can power the MP3 player. The cigarette lighter plug
is also used so the gizmo can be charged up while driving to and from hunt meets
Again like the MP3 player, wires were soldered into the lighter plug to allow it
to be connected to the battery inside the box -
The earphone leads are very fine so take care when stripping the insulation back.
Figure 7 shows what you should expect to see although the colours may differ. Two
wires will be the same colour and these I took as the 'common'. One of the leads
I simply snipped back then and used only one pair because this gizmo is mono only.
The wires are so fine I connected these to the gizmo (red-
Everything else was fairly straightforward if you know basic electronics and can
follow the circuit diagram. I glued the amplifier in place and riveted a bracket
to the box behind the lighter plug to prevent it being pushed inside. I only wedged
the battery in place (using glued rubber blocks) because after 6 years or so you
may want to replace it. The negative battery terminal should be earthed to the case.
The power switch should be wired up to allow the battery to be charged in the 'OFF'
position and then power go into the amplifier and voltage converter in the 'ON' position.
Blue connectors will fit the battery and the power switch. I would recommend using
the red bullet connectors to join wiring instead of the blue ones I used for the
simple reason that space is tight! Figure 9 shows that everything will fit in the
box nice -
All you need now is a recording to play -
To be honest the small HSA-
"That's crap -
"Next one down -
"All I need now is an amplifier. Aah, here's an amplifier that kicks out 40W with
a 4ohm speaker at 16V. Well, the speaker is 8ohm and if I use a 12V battery that
should drop the power down nicely to maybe about 20W -
That just about sums up the electronic design work!
The following table lists the parts you will need:
1 30W 8ohm Horn Speaker 19.99 (XQ97F)
2 40W (6-
3 12V 2.2Ah Battery 11.99 (MM23)
4 128MB MP3 Player 24.99 (L05BF)
5 Car Power Adaptor 8.99 (L17AR)
6 Car Power Extension Lead 2.99 (BV47)
7 Rocker Switch 1.99 (N50BW)
The horn speaker for this gizmo is massive (figure 10), so to cut down on the bulk,
all the electronics fit around the horn. This unfortunately requires a specialist
case which has to be made out of metal. If you don't have any sheet metal in your
garage Maplin again save the day by selling sheets of aluminium so you can make your
own box. The dimensioned design is shown in figure 11. It consists of 2 pieces which
can be joined together with self-
I used the same basic techniques as previously described with a few notable exceptions:
This amplifier requires a heat sink and so I used the aluminium case for this purpose and riveted the amplifier directly to it.
The battery ideally requires suspending next to the horn speaker in this project
so it is advisable to rivet some small brackets to the case and zip-
I used thicker wires between the battery and amplifier because this amplifier
can draw 4Amps, so use some 4-
The amplifier was again very straight forward to wire up but the circuit does differ from the smaller gizmo and the circuit diagram is shown in figure 12.
When things go wrong...
So you've put it all together and it doesn't work -
Check your wiring to make sure you have connected each component to the next one in the right order and in the right way using the circuit diagram as a guide.
Check the connectors are all firmly crimped -
For both the gizmos I built I had problems with the power switches. The power switch doesn't light on the big gizmo and on the small one didn't work at all. To test this out simply bypass the switch and wire up the battery directly.
Check the battery is properly charged with a voltmeter.
Using a Gizmo
Most sabs have probably used a gizmo before so I won't patronise anyone with explaining the tactics.
Flick the power switch to 'ON'.
Switch the MP3 player 'ON' and if it requires it press 'PLAY'. You may then hear a quiet version of the hounds in cry. This is due to the way the speaker is connected.
Press the little red push-
You may have to adjust the volume on the MP3 player.
Use the hunting horn and holloa before activating it because it drowns everything else out!
Keep your eyes open and watch your colleagues and hunters (if any are around) because all you can hear is the gizmo.
Be prepared to run with the hounds!
Your ears may be ringing for a few moments after using the large gizmo but I haven't suffered anything more permanent than that. You may have to adjust the volume of the MP3 player for the optimum effect. For both of these gizmos I would recommend leaving the power switched on in the field to avoid having to switch on the MP3 player and adjusting the volume every time.
I also recommend fitting a shoulder strap to the large gizmo for the poor fool -
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