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--- projects:crazyflie:hardware:explained [2012-12-03 19:24]
tobias [Crazyflie KIT electonics explained]
+++ projects:crazyflie:hardware:explained [2013-01-12 15:54]
tobias [Specification]
@@ Line 60: / Line 60: @@
 It is also possible to manually solder-mount a MS5611 pressure sensor afterwards if that is of interest. This could make it possible add an altitude-hold functionality. No SW support now though.
 ===== Expansion header =====
+{{:projects:crazyflie:hardware:crazyflie_expansion_header_wiki.png?300 |}}
+The expansion header is located on the left side of the Crazyflie. It is a 10x2 pin 1.27mm (0.05") pitch trough-hole footprint which comes unmounted. The idea with the through-hole is that it makes it possible to mount expansion boards on either or both sides. It would even be possible to stack several on top of each other.
+The header is divided into two parts. The JTAG part, pin 1 to 10, and the buss/power part, pin 11 to 20. The UART RX/TX is located on the JTAG part because on many FTDI based JTAGs it is possible to use one channel for serial communication which can be very handy when debugging.
+Header pin description
+^^ Pin nr ^^ Name ^^ Description ^^
+|| 1  || VCC || Digital supply voltage ||
+|| 2  || TMS || Test Mode Select ||
+|| 3  || EXT_I2C_SCL/TX || I2C clock or UART TX ||
+|| 4  || TCK || Test Clock ||
+|| 5  || EXT_I2C_SDA/RX || I2C data or UART RX ||
+|| 6  || TDO || Test Data Out ||
+|| 7  || N/A || Could be used for keying ||
+|| 8  || TDI || Test Data In ||
+|| 9  || DGND || Digital ground ||
+|| 10 || SNRST || System reset ||
+|| 11 || EXT_SPI_CS/AIN4 || SPI chip select or analogue in 4 ||
+|| 12 || EXT_SPI_MOSI/AIN5 || SPI Master Out Slave In chip or analogue in 5 ||
+|| 13 || EXT_SPI_SCK/AIN6  || SPI clock or analogue in 6 ||
+|| 14 || EXT_SPI_MISO/AIN7 || SPI Master In Slave Out chip or analogue in 7 ||
+|| 15 || VCC || Digital supply voltage ||
+|| 16 || VCOM || Battery/USB voltage ||
+|| 17 || DGND || Digital ground ||
+|| 18 || DGND || Digital ground ||
+|| 19 || AGND || Analogue ground||
+|| 20 || VCCA || Analogue supply ||
 ===== 2.4GHz radio =====
 ===== Motor drivers =====
+{{:projects:crazyflie:hardware:motor_driver_wiki.png?200 |}}
+The motor driver, as we use brushed motors, is a simple pull down mosfet as shown in the schematics. There is also a free-wheel diode to take the Back-EMF spikes generated by the motor during PWM-ing.
+The mosfet we choose is the PMV31XN in a SOT-23 package. It can handle a lot of power and should be good for at least 3A each. The most important property of the mosfet though might be the on resistance (Rdson) since it effects the amount of power the motors can make use of. We measured the PMV31XN Rdson at 2.8V G-D voltage and 0.8A D-S current to be ~40 mOhm.
 ===== Motors =====
+We use a coreless brushed DC motor 6x15mm.
+==== Specification ====
+**Electrical**
+|| Description || Value ||
+|| Rated voltage || 4.2 V Max ||
+|| Nominal voltage || 3.7 V ||
+|| No load speed || 45000 ±15% RPM ||
+|| No load current || 80 mA Max ||
+|| Starting voltage || 0.8 V Max ||
+|| Rated load speed || 21000 ±15% RPM ||
+|| Rated load current || 810 mA Max ||
+|| Resistance || 2.3 ±20% Ω ||
+**Mechanical**
+|| Description || Value ||
+|| Shaft diameter|| 0.8 mm ||
+|| Motor diameter || 6 ± 0.05 mm ||
+|| Motor length || 15 mm ||
+|| Weight || 1.6g approx.||

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