Solder instruction and circuit of the USB IR receiver
As mentioned at the introduction, the construction is not that easy
as for the serial
but it should not be a big problem for an amateur solderer to solder the
circuit referring to the following instruction.
Since I wanted to build up everything as small as possible, it took me
quite some time fiddling around to develop the following circuit.
But first let me explain a bit the function of the components, because
the one or the other could be rather interested to know about the effect
of a single component.
Function of the components ...
According to the former IR circuits I used for this one also the TSOP
1738 as IR receiver, which is connected to a 5 volt power source at pin
Pin 3 of this 38 kHz IR receiver is the output for the received signal
and, last, but not least, there is even the connection for GND at pin
With the 4.7 µF Elco, the 10 µF Elco and the 100 nF capacitor
the basic power supply is smoothed by a multi level absorption of peaks
in the power supply of the USB connection.
Further on there is the 1.5 k resistance, which works as a pull up resistance
between the negative data line and the 5 volt power supply of the USB
connection with the purpose to stabilize the logical signal.
The very core of the USB receiver is the programmed Atmel IC, which is
here operated with a 12 MHz quartz and performs the communication between
the PC and the IR receiver.
Altogether not too complex, yet not really as simple as the former serial
Let us now quickly move to the wiring diagram, which - due to the finding
of the optimal arrangement of the single parts - took me more time than
The wiring circuit ...
(to enlarge the image click on the circuit)
How to solder all together ...
First of all we take the parts one by one and fix them to the PCB (referring
to the next image),
while fixing the two capacitors with the plus (+) pole up !!!
Here's a picture of the different Tantal capacitor types with the right
Fix the IC socket with the little notch up (also shown on the image).
This notch is the orientation point to fix the IC correctly later on.
Here we have a plotting of the backside of the PCB to see in which direction
cables have to be bent and how long/short the wires have to be to fit
to the following solder process (the notch of the IC is now down !)
At this point I have to intend on inspecting everything
3 times to avoid a wrong soldering !!!
Obviously this is the most annoying part of the whole work, but conscientious
preparing is indeed the most important part, because we avoid mistakes,
which are later almost impossible to cancel.
The soldering iron can already be heated during this work, because we
will start in a second :-)
Now we simply solder all positions as described in the following image.
If possible do not solder more spots than necessary, because afterwards
we want to fix the USB cable.
In order to get the positions of each part clear I created an overlay
of the upper and lower part of the PCB
to have them both in one view.
At last we solder the 4 wires of the USB cable with
black = GND, white (or yellow) = data (-), green (or blue) = data (+), red = VCC + 5 volt.
Sometimes USB cables have different colors.
Here is a table with some possible USB cable colors (just in case your cable is NOT red, black, white and green):
This is the finished lower part of the soldered PCB without the green
This is again an image of the finished USB receiver with USB connection
That's it :-)
Best will be - for a last time - to check again all connections and
the positions of the capacitors.
Fix now the IC with the notch placed to the free space of the IC socket
before plugging in the USB plug and
the following installation of the drivers.
Additionally I recommend you to use a shrinking tube or a piece of tape
to isolate the lower part of the PCB,
whereas I treated the
kit in the fanshop to a piece of shrinking tube, which is covering
exactly the whole PCB
with all single parts.
The vault of the infrared receiver may of course not be covered, because
this is the receiving part !!!
Copyright 2005 by www.ocinside.de !