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(Hardware)
Zeile 5: Zeile 5:
  
 
==Hardware==
 
==Hardware==
 +
 +
bare PCB, no container (yet)
  
 
===MCU===
 
===MCU===
 +
 +
[http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1031/LN775/PF216839 STM32F100C8T6]
 +
 +
Reasons:
 +
 +
* Cheap
 +
* Powerful (up to 24MHz), Cortex-M3
 +
* Lots of GPIOs
 +
* Small (LQFP48)
 +
* 3.3V levels
 +
 +
Alternatives:
 +
 +
* STM32F0xx
 +
* Freescale Cortex-M0
 +
* MSP430G2553
 +
* [https://www.semiconductorstore.com/cart/pc/viewPrd.asp?idproduct=48872 RFD22301] (probably far too expensive, but it includes the RF stuff)
 +
* ATmega328P @ 3.3V, 8MHz
  
 
===RF===
 
===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?===
 
===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)
 +
* [http://www.sharpmemorylcd.com/1-28-inch-memory-lcd.html Sharp Memory Display]
 +
* Liquid Crystal display without a backlight
 +
* Two flipdot-dots?
  
 
===Buttons===
 
===Buttons===
 +
 +
5x5mm button
 +
 +
Reasons:
 +
 +
* Cheap
 +
* Large enough for humans to handle
 +
 +
Alternatives:
 +
 +
too many to list
  
 
===Leds===
 
===Leds===
  
 +
None
  
 +
Reasons:
  
 +
* LEDs require a lot of power
 +
* Not a lot of expressiveness with them
  
 
==BOM==
 
==BOM==

Version vom 12. Februar 2014, 05:32 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


Who

Overflo

anlumo