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NRF shield
 
NRF shield
 
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[[Datei:Moderator-Raspberry-Side.png|gerahmt|Raspberry Pi-to-nRF24L01+-Module Adapter]]
 
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==Who==
 
==Who==

Version vom 12. Februar 2014, 05:07 Uhr

What

A voting device, similar to edubuzzer but with the design-goal of being super-cheap.


Hardware

bare PCB, no container (yet)

MCU

STM32F100C8T6

Reasons:

  • Cheap
  • Powerful (up to 24MHz), Cortex-M3
  • Lots of GPIOs
  • Small (LQFP48)
  • 3.3V levels

Alternatives:

  • STM32F0xx
  • Freescale Cortex-M0
  • MSP430G2553
  • RFD22301 (probably far too expensive, but it includes the RF stuff)
  • ATmega328P @ 3.3V, 8MHz

RF

nRF24L01+ module

Reasons:

  • Cheap
  • Small
  • Relatively low-power
  • Easy to use
  • Lot of libraries for it
  • Supports point-to-point, broadcasts and multiple channels
  • Special module versions available with ranges of up to 1100m
  • Uses 3.3V levels

There are a lot of modules with that chip available. Most of them use a 2x4pin 0.1" connector with a standard pinout. There are also much smaller SMD modules available, but these are more expensive and do not seem to have a standard pinout or layout.

Alternatives:

  • Bluetooth 4.0 Low Energy (nRF8001, BLE113-A, CC2541, …)
  • 433MHz RF wireless transmitter module (one-way only!)
  • 802.11b/g/n (CC3000, HF-LPB, …)

Display?

Nokia 5110 display

Reasons:

  • Cheap
  • Small
  • Low-power
  • Lot of libraries for it
  • Can mount directly to the PCB, no expensive/rare connector required
  • Uses 3.3V levels

Alternatives:

  • Just some status LEDs (takes a lot of power)
  • Sharp Memory Display
  • Liquid Crystal display without a backlight
  • Two flipdot-dots?

Buttons

5x5mm button

Reasons:

  • Cheap
  • Large enough for humans to handle

Alternatives:

too many to list

Leds

None

Reasons:

  • LEDs require a lot of power
  • Not a lot of expressiveness with them

BOM

Table here..



Basestation

RaspberryPi

NRF shield

Raspberry Pi-to-nRF24L01+-Module Adapter

Who

Overflo

anlumo