108 Silicon chip Australia’s electronics magazine siliconchip.com.au
Your compile error indicates that
RTClib is missing. A zip of that library
is included in the software download
package.
Please make sure you have installed
it before trying to compile the sketch,
as per the instructions on page 32 of
the August 2017 issue. Doing so should
eliminate that error message.Powering mic preamp
from two 9V batteries
I am looking for a circuit of a coil mi-
crophone preamplifier circuit which
can run from two 9V batteries con-
nected in series. It can be transistor
or op amp based. Have you published
such a circuit in your magazine? (P.
H., via email)- We haven’t published a circuit ex-
actly as you describe, but we have
published two microphone preamps
which could be easily modified to run
from ±9V rails produced by two bat-
teries in series.
The first one is the Balanced Mi-
crophone Preamplifier (August 2004;
siliconchip.com.au/Article/3585). The
changes required are: omit REG1 and
join its input/output terminals with a
GPS wires to CON3 is different be-
tween Fig.2 and the photo. The wir-
ing is reversed in the photo. Both pho-
tos show the wire sequence to be red,
blue, green, black and yellow, while
Fig.3 shows the sequence reversed.
Which is correct?
Also, upon trying to compile the
supplied code, I get the following er-
ror:
Arduino_Data_Logger.ino:18:20:
fatal error: RTClib.h: No such
file or directoryIt would seem that the real-time
clock file hasn’t been downloaded in
the files from the Silicon chip web site.
Thanks for the help, keep up the Ar-
duino projects. (P. L., Tabulam, NSW)- The photos in the August 2017 is-
sue are of a veroboard prototype. You
can tell because the PCB is red. The
connector for the GPS in that version
was installed rotated 180° compared
to the final PCB. You can see pho-
tos of the final PCB in the September
2017 issue.
If you compare the photos of the fi-
nal PCB to the overlay diagram, Fig.2,
the colour coding for the wiring to
CON3 is consistent.
gests that the 116μs pulse width is not
the problem. 116μs is well within the
100μs-10ms pulse width range speci-
fied in the DCC standards.
It’s more likely that this has to do
with the limited current that the 555
can supply, as mentioned in the article.
Its absolute maximum value is 200mA,
and it is already sagging quite badly at
100mA. It may be that the NCE chips
handle the sagging voltage better, or
don’t need as much current to operate.
We published a DCC Booster design
in the July 2012 issue which might
help with this (siliconchip.com.au/
Article/614).
We are also working on a DCC base
station that will be capable of much
higher current, so perhaps this is some-
thing you can consider building when
we publish it.
Arduino Data Logger
queries
I’ve finished assembling the Ardui-
no Data Logger from your August and
September 2017 issues (siliconchip.
com.au/Series/316) and have a couple
of questions.
Firstly, the colour coding for the