PIC Tutorial - Wireless Boards
Wireless Boards
This
time we actually need two boards, one transmitter board, and a receiver
board as well. The licence free radio modules I'm using are from
RFSolutions,
the RTFQ1 (transmitter) and RRFQ1 (receiver), they are FM modules, with a
range of up to 250m, mine work on a frequency of 433.9MHz, and they are
available at low cost from a number of sources. I've provided a copy of the
datasheet if you want to have a read of
it.
The
transmitter works off a lower voltage, so we've got a small 3.3V zener diode
(D1) and a 68 ohm resistor as a regulator to provide it with 3.3V, a 10K
resistor to interface the 5V logic to the 3.3V logic, and there's a couple
of decoupling capacitors.
The
receiver board is very straight forward, it's simply the module and a few
decoupling capacitors, there is an extra output available, which is an
analogue voltage related to the signal strength, but I've not connected
that.
I used
these modules because they are low cost, and easily available, but there's
no urgent need to use these particular modules, any similar devices should
be fine, but the layouts will obviously be somewhat different.
 |
This
is a top view of the Wireless TX Board, it consists of one RTFQ1, two
resistors, two capacitors, one zener diode and five wire links. |
 |
A
bottom view of the Wireless TX Board, there are twenty seven track
cuts, although some of them are the complete removal of track sections
- this was done because the manufacturers of the modules advise you
NOT to use Veroboard to mount the modules. |
 |
This
is a top view of the Wireless RX Board, it consists of one RRFQ1, one
electrolytic capacitor, two capacitors and five wire links. |
 |
A
bottom view of the Wireless RX Board, there are fifty track cuts,
although some of them are the complete removal of track sections -
this was done because the manufacturers of the modules advise you NOT
to use Veroboard to mount the modules. |
For
anyone who's interested, I'm now using Abacom products for my diagrams, 'sPlan
5.0' for the circuits, and 'LochMaster 3.0' for the layouts.