Quadrocopter old info

The Quadrocopter Project

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= Old Info =

Microcontrollers we considered
NXP LPC1769
 * ARM Cortex-M3
 * 120MHz
 * 32 bit
 * 512KB flash
 * 64KB SRAM
 * DMA
 * 32 bit multiply and accumulate!
 * 10/100 ethernet
 * USB 2.0 Host/Device/OTG
 * 12-bit ADC, 10-bit DAC
 * $12.80

LPCXpresso LPC1769

http://hackadaycom.files.wordpress.com/2010/04/esc-lpcxpresso.jpg

The right side of this board is a LPC1769 breakout board. It include a ethernet interface chip and serial flash. The left side is a programmer that only works with the Code Red LPCXpresso development tools. Those tools only allows us to use a quarter of the M3s 512k code space. It needs to be registered for it to work.
 * $31.73
 * more info

PIC32MX695F512L-80I/PT-ND
 * 80 MHz with internal oscillator, 80 MIPS
 * 32 bit
 * Program memory: 512K x 8
 * Ram: 128K
 * 3.3V
 * 85 I/O pins
 * can handle 5V I/O
 * pins are not re-mappable
 * $12.27

DSPIC33FJ256MC710A-I/PT-ND
 * 40 MIPS
 * 16/24 bit
 * Program memory: 256K x 8
 * Ram: 30K
 * 3.3V
 * 85 I/O pins
 * can handle 5V I/O
 * pins are not re-mappable
 * $10.33

DSP Engine Overview The DSP engine features a high-speed, 17-bit by 17-bit multiplier, a 40-bit ALU, two 40-bit saturating accumulators and a 40-bit bidirectional barrel shifter. The barrel shifter is capable of shifting a 40-bit value up to 16 bits right or left in a single cycle. The DSP instructions operate seamlessly with all other instructions and have been designed for optimal real-time performance. The MAC instruction and other associated instructions can concurrently fetch two data operands from memory while multiplying two W registers, and accumulating and optionally saturating the result in the same cycle. This instruction functionality requires that the RAM memory data space be split for these instructions and linear for all others. Data space partitioning is achieved in a transparent and flexible manner through dedicating certain working registers to each address space.

PIC24FJ256GB210-I/PT-ND
 * 32 MHz, 16MIPS, 8MHz internal
 * 16 bit
 * Program memory: 256K x 8
 * Ram: 96K
 * 3.3V
 * 84 I/O pins
 * can handle 5V I/O
 * pins are re-mappable
 * $9.53

ATMEGA2560V-8AU-ND
 * 8 MHz
 * 8 bit
 * Program memory: 256K x 8
 * Ram: 8K
 * 1.8V - 5V
 * 86 I/O pins
 * pins are not re-mappable
 * $19.04

ATXMEGA256D3-AU-ND
 * 32 MHz
 * 8/16 bit
 * Program memory: 256K x 8
 * Ram: 16K
 * 1.8V - 3.6V
 * 50 I/O pins
 * pins are not re-mappable
 * The XMEGAs are buggy
 * $9.05

Sensors we considered
Accelerometer - ADXL345
 * $8.64
 * 3 axis
 * I2C interface
 * datasheet

Accelerometer - MMA7455LT
 * $2
 * 3 axis
 * I2C interface
 * datasheet

Gyro - L3G4200D
 * $14
 * 3 axis
 * I2C interface so we don't expose any analog signals to a noisy motor environment
 * datasheet

Magnetometer - Honeywell HMC5843
 * I2C
 * $22.56
 * datasheet

Magnetometer - Freescale MAG3110
 * I2C
 * $2.38

Barometric Altitude and Temperature Sensor - Bosch BMP085
 * 25cm resolution
 * $8.90
 * datasheet

Barometric Altitude and Temperature Sensor - Freescale MPL3115A2
 * Pressure output can be resolved with output in fractions of a Pascal
 * Pressure: 20-bit measurement (Pascals)
 * Altitude: 20-bit measurement (meters)
 * Temperature: 12-bit measurement (°Celsius)
 * Resolution down to 1 foot / 30 cm (maybe even 2cm!)
 * datasheet
 * new part. not available at Digikey or Mouser. If we can buy one, the price is about $4 in quantities of 250 pieces, so not likely to be cheaper than the Bosch device.

Decisions
Do we use 1 or 2 microcontrollers? What are the advantages to using 2 microcontrollers? To select between 2 sets of code?
 * A: simple and reliable
 * B: fancy and experimental

ArduPilotMega, PIC, AVR, or ARM?
 * PIC - support available from Ron C. and Aaron, Luc and Guy have programmers, easy to use
 * ARM - support available Michael G., steep learning curve
 * AVR - Doug is familiar with it, compatible with Arduino

Attributes to consider

 * brand - Turnigy has a good reputation
 * vibration - This will show up in the accelerometer readings, so the lower the better
 * price
 * maximum current
 * kv rating(RPM per volt) - It was said somewhere that it should be less than 1000 to minimize vibration
 * performance as reported by those that have used them on quadrocopters

Contenders
Turnigy 2217
 * this fellow found that they had major vibration issues

KDA20_22L
 * www.aeroquadstore.com out of stock
 * Hobby King out of stock

BP A2212-13
 * www.aeroquadstore.com It's in stock!
 * $16, 53g, 1000kv, ball bearings

What to use for rods

 * Superior carries 1/2" square aluminum tubing for 75 cents per foot. It is 1/16" thick (too thick and heavy)
 * carbon arrow shafts?
 * Jim - You can get arrows at Walmart


 * Carbon Fiber Square Tube

An unused idea for the frame




There are 4 arms made of wood. The dimensions are 1/8W" x 3/4"H x 20"L. They are easy to make and cost nothing and therefore cost nothing to replace. They will fit into slots in the hub. The motor will be mounted 6" from the end of the arm using the same brackets that are used in the hub. The outer end will either be attached to each other with some kind of wire, or a sheet of Coroplast. They weigh 15g each.

The hub is made of 8 plastic brackets sandwiched between 2 layers of Sintra (3mm x 4" x 4"). The brackets will be cut out of a plastic cutting board.