RFX 328p dev/dep board w/ nRF24L01+ headers (Kit)
The RFX 328/nRF24l01+/Proto dev board can be ordered as a bare PCB or a kit. A 3v3 board running at 16MHz, it has been designed as a minimalist, low-cost deployment board for wireless nRF24l01+ enabled projects. It is an Uno-class dev board with integrated nRF24L01+ module headers, and a small but usable prototyping area.
It uses all through-hole components, so nothing more than basic soldering skill and equipment is required to assemble it.
It supports the standard Arduino shield header layout, as well as a second breadboard compatible (i.e., proper 0.1″ pitch grid-aligned) header layout, so you can design your own “shields” using common 50mm (or wider) proto board (just check you’ve got at least 18 through holes at 0.1″ pitch to span the second header layout).
Plugging one of these onto a 5cm x 7cm proto board is a great way to instantly get a lot of additional prototyping real estate (“great” as in “super easy and inexpensive!”).
For project flexibility, there is provision for two nRF24L01+ module connection headers on the dev board: One header connects to the hardware SPI pins D11-D13, while the other header connects to alternative set of pins (D4-D6) for a “bit-banging” software SPI implementation, if preferred. (For both headers, IRQ pin is set at D2, CE is D3 and CSN is D7.)
If you want to run the board as a 5V board, just use a 5V regulator in place of the 3v3, but then you need to use a nRF2401+ proto shield or equivalent with its own 3v3 regulator to connect a nRF24L01+ module. One advantage of this arrangement, however, is that you end up with two fairly beefy power supply rails, at both 3v3 and 5V, for projects requiring dual voltages. (Keep an eye out on the docs pages for details of an example projects that does just this.) Far superior to the standard Arduino board dual rail specs in this arrangement!
Another small but important upgrade is the provision for the inclusion of a 10uH inductor in the AVcc power supply section. This results in significantly better analog input reading stability and precision. This inductor is actually specified in the Atmel design guidelines, but unaccountably hasn’t been included in the standard Arduino board designs (although Massimo Banzi has indicated this omission may be addressed in future board revisions.)
To keep cost, complexity and size low, it is without USB connectivity, so it must be programmed using either a programmer (e.g., a USBasp) via the ICSP header, or a USB-to-TTL serial adaptor (if a serial bootloader is installed on your 328p chip.)
List of passive components (see photo):
1 Voltage Regulator, LD11173v3
1 xtal (16MHz)
2 caps, 22pF caps (ceramic, for xtal)
3 caps, 0.1 uF (ceramic, bypass)
1 cap, 10uF (electrolytic)
R1 10K (Reset Pullup)
R2 1K (LED)
L1 10uH (AVcc filter)
1 28-pin DIL socket (for Atmega328p)
nRF24L01+ connectors sockets:
2 female headers (2×4)
ICSP programming connector:
1 male header (2×3)
nRF24L01+ power supply jumper:
1 male header (1×2)
3 female headers (1×8)
1 female header (1×6)
Designed for easy assembly, full assembly instructions come with kit.
Kit documentation (pdf):