■ PHOTO 5. Like the RX-AUDIO- 24, the TX-AUDIO- 24
carries an integral antenna along with the radio
electronics in a compact 1.8 x 0.55 inch package.
Nuts & Volts website ( www.nutsvolts.com). My assembled
wireless guitar system receiver support board is pictured
in Photo 3.
I’ve listed the part numbers for the 0805 SMT
tantalum capacitors in the NOTES area of Schematic 1.
The RX-AUDIO- 24 interfaces with the wireless guitar
system receiver support PCB by way of a 40-pin 2 mm
connector. The 2 mm connector can be had from Mouser
as part number 855-M22-7142042. You’ll find that the 2
mm connector fits perfectly on the edge of the PCB. Be
sure to solder all of the 2 mm connector pins on both
sides of the PCB. Schematic 1, Photo 3, and the Express
PCB layout file provide you with more than enough
component identification and placement information to
assist in a trouble-free hardware build process. Once
you’ve checked your work, you can attach the RX-AUDIO-
24 module to the support PCB as shown in Photo 4.
THE TX AUDIO 24
Schematic 2 pretty much says it all. The TX-AUDIO- 24
is a stereophonic digital transmitter that only requires the
support of a power source and four external components
for proper operation.
As you can see in Photo 5, the TX-AUDIO- 24
interfaces to its support electronics via an eight-pin 2 mm
THE DESIGN CYCLE
header. If the USER_BIT input is not utilized, the
TX-AUDIO- 24 only requires five of the eight header pins
to be connected to external support circuitry. Basically, all
the TX-AUDIO- 24 needs from us is a power source and an
The TX-AUDIO- 24 requires a power supply voltage
between + 3. 6 and + 5.0 volts DC. The current consumption
is just a bit higher than the RX-AUDIO- 24 coming in at 92
mA when the wind isn’t blowing. As one would expect,
the TX-AUDIO- 24 transmits in the 2.4 GHz ISM band
using one of eight channels that are spaced 9 MHz apart.
A maximum input level of four volts peak to peak can be
applied at the TX-AUDIO- 24’s audio inputs, which is well
above the raw pickup output of most guitars.
1. ALL RESISTORS 0805 SMT PACKAGE
2. ALL CAPACITORS 0805 SMT PACKAGE
3. C1 - DIGI-KEY 511-1471-1-ND
4. C3/C4 - MOUSER 80-C0805C105M4R
5. C5 - DIGI-KEY 511-1452-1-ND
6. PHONEJACK MOUSER 16PJ509
■ SCHEMATIC 2. SW1 is
used to switch to one of
eight available channels.
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