Mbed Starter’s Kit for Fall 2017

GT ECE mbed Inventor’s Kit

Sparkfun will be selling an mbed starter’s kit (mbed + parts kit) to support mbed projects at Georgia Tech in ECE 2035, 2036, and 4180 this semester. Here is a list of the parts, links to where they come from, some info on how to use them with mbed, and approximate quantity 1 prices. Shipping and tax are not included and parts must be ordered from four different places so the shipping costs add up, if you buy your own directly. You can also order your own or get replacements using the links provided. The price is still lower than ordering it all directly and you do not need to wait for parts to arrive and then solder everything. Sparkfun has already soldered the parts for you in the kits. If you get your own, some soldering is required. A breadboard and jumper wire kit is also needed to assemble projects, if you do not already have them and HKN also sells these at the start of the semester. HKN students volunteer their time to provide the breadboard and wire kits and any money made funds an ECE student scholarship.

Buying mbeds

HKN mbed sales at Georgia Tech

Starting Spring 2015, Sparkfun has packaged the mbed kit based on the one used at Georgia Tech. This kit comes with all of the parts and the breakout board pins already soldered. Sparkfun will be selling this kit going forward (no longer ECE). Information on parts in the mbed starter kit can be found at https://www.sparkfun.com/products/12968 . The new kit has a small breadboard, jumper wire kit, and accelerometer. The pushbuttons are a bit larger than the older kits.

Contents of the mbed inventor’s kit

The ARM mbed module

Mbed – LPC1768 $49.95

The ARM mbed processor module with USB cable and a user account for the cloud compiler and storage

Be very careful not to bend mbed’s pins during insertion and removal!!!

Watch this video showing how to protect your mbed’s pins

16 by 2 line LCD $14 - Replaced with newer technology Color LCD Spring 2014

Code provided using just a C++ printf()on mbed

Note: use 5V on LCD supply (not 3.3V like mbed cookbook example) and pin 1 is upper left in image.

Use the 1K ohm resistor in the kit to tie the LCD’s contrast pin to ground. The optional backlight LED on LCD pins 15 and 16 uses a bit too much power to run off of USB power, if anything else is hooked up to mbed.The backlight LED would also need a 5 ohm resistor or diode to drop the voltage from 5 to around 4.2 volts.

1K ohm resistor used for LCD contrast

Mbed pins

GND

5V- VU

GND via a 1K ohm resistor

P15

GND

P16

N/C

P17

P18

P19

P20

TextLCD function

GND

VCC

VO – contrast adjust

LCD pin number

uLCD-144-G2 128 by 128 smart color LCD $31

Displays text, graphics, images, and videos in color.

4 Pushbuttons – fit well in breadboard $2 for 4

Pushbutton code examples and tutorial

Shiftbrite RGB LED $5 Replaced with RGB LED Spring 2015

2^30 colors possible - code and tutorial

Sparkfun RGB LED – code and tutorial

TMP36 Analog Temperature Sensor $1.50

Easy to read temperature using A/D, plugs into breadboard

Code example to scale and read temperature

Looks just like the 2N3904 transistor in the kit, so look for the tiny gray part number marks on the package. Pay attention to the case orientation (note flat side), be careful not to hookup power and ground backwards and blow it out.

Ethernet Magjack and Breakout Board $3

All that is needed to connect mbed to the Internet. Different magjacks use different pins, but look exactly the same, so use setup in table below:

(until Sparkfun switches magjack brands)

Mbed	adapter
TD+	P1
TD-	P2
RD+	P7
RD-	P8

The pins are labeled on the PCB and the jumper wires have to run under the PCB. This is an example to try first after wiring it up and a valid DHCP IP address is not needed. It just displays the packets flying by on the network.

Note: For security, many DHCP networks only provide IP addresses to computers with enabled MAC addresses. Some other steps are needed to enable mbed to use DHCP to get a valid IP address on the GT network. You may need to bridge a spare network jack to the Internet on your laptop, or enable a temporary connection to GTLawn.

Audio Breakout board and audio jack $3

Code example and tutorial – wiring and circuit details are near the end of this web page

Used for common 3.5mm stereo audio in/out connections

Can record audio using mbed’s A/D or play audio wave files using mbed’s D/A using a PC or PC speakers

Micro SD card – adds up to 4G of file storage $10

Mbed has 2M of flash onboard, but some space is also needed for code. Macs don’t like it if you ever use it (it locks the flash drive files).You need this board to add more storage using a Micro SD card. A Scandisk Micro SD 2G card $10 also comes with the kit. Larger ones and some other brands might not work. Use eight character filenames with a three character extension (FAT file format). File system drivers are provided.

USB A socket Breakout board $4

Can connect a mouse, keyboard or small flash drive

Other USB devices need driver code. Shipped from UK.

Small 8 ohm speaker $2 A new PCB mount speaker will be used starting Spring 2014 (shown on right).

It plugs directly into a breadboard and works the same as the earlier speaker with wire leads soldered on.

Code example and tutorial on using the speaker for audio output

Can be used for audio output from a *wav file using the 2N3904 driver transistor provided in the kit.

.1 inch header Pins for all Breakout boards 20 pins $3 - several strips are needed for everything. Needed for all of the other breakout boards and LCD pins. The more expensive round gold machine pins work quite a bit better on protoboards than the cheaper square ones. Must be soldered on, if you buy your own breakout boards. ECE solders them for you in the kit.

Parts are in a plastic divider box to help avoid the problem of bent pins.

Once Again: Be very careful not to bend pins during insertion and removal!!!

Hardware Development using a Breadboard

The mbed modules and the breakout boards plug directly into a student breadboard enabling students to build rapid prototypes of embedded devices. HKN also sells the breadboard and jumper wire kits that are used in the earlier digital logic laboratory. The clock project seen below automatically connects to the Internet and sets the clock using an NTP server. Power for projects is provided using the USB cable. The USB cable is also used to download code from a PC and send program output to the PC.

Internet Clock Project on Breadboard

Software Development - Tools and Documentation

Mbed’s C++ I/O APIs are described in the handbook. Code examples for many I/O devices can be found in the cookbook. For software development, the easy-to-use mbed cloud compiler is typically used. Projects from the cloud compiler can also be exported to the offline compiler. The offline compiler takes a bit more time and effort, but it supports breakpoints for debugging complex programs. For the offline compiler, download the free demo version (<32K code size) of the ARM/Keil MDK compiler. To enable the offline compiler’s full features, you must start the compiler and then connect over the network using VPN with your GT password to Georgia Tech’s FlexLM license server. Use File->License Mangement ->FlexLM. Then set the FLEX server to 8224@ECEWINSRV1.ECE.GATECH.EDU and the full version will be enabled.

GT ECE students working on mbed projects

Need Additional Parts for Design Projects?

There is a large assortment of additional sensors, displays, and I/O connectors available for use with mbed on breadboards that are not provided in the kit. For custom student design projects, there is a large table with hyperlinks showing where they can be purchased at mbed breakout boards and I/O connector boards. A large number of interesting GT student design projects have already used mbed.

GT student design projects built using mbed