The document describes the process of developing a prototype SMS display device using an Arduino and mbed microcontroller board. It details how the author designed their own printed circuit board using EagleCAD software, had it manufactured, and assembled it with the microcontroller and mobile broadband dongle. The completed device is then able to display incoming SMS messages on an LED matrix. The document concludes by discussing some potential improvements and uses for the SMS display device.

1. From idea to finished product
By Andrew Lindsay at Reading Geek Night 09/07/2013
@AndrewDLindsay

2. About me
 Started programming Sinclair ZX80 as a kid
 Software developer for over 25 years, now freelance.
 Experience of TV, Government, Telecoms, ISP, Transport,
Utilities and Finance.
 Instrumentation and Embedded Systems Roles
 Java, C, C++, Basic, Pascal, web etc…
 Interest in microcontrollers re-ignited with Arduino
 Then mbed and ARM processors
 Regular at IoT London meetups

3. The idea
 IoT London Meetup number 9, June 2012
 Vodafone demonstrating K3370 Mobile broadband
dongle and mbed connected to printer to display sms
 Already used Arduino with multiple LED Matrix displays to
create network enabled scrolling display
 Familiar with mbed technology

4. Prototype

5. Beyond a prototype
 Design own PCB
 Learn EagleCAD for schematic and PCB layout
 Generate gerber files
 Have small batch of PCBs manufactured
 Used Seeedstudio Fusion PCB service

6. Schematic

7. PCB Design

8. Creating output

9. Checking PCB - WebGerber

10. Manufacture

11. Boards arrive from China

12. Building the board #1

13. Building the board #2

14. Completed Board

15. SMS Display

16. Uses
 Integrate with services that send SMS, e.g. IFTTT
 Display Foursquare checkins, weather alerts, Google
calendar events.
 Rude messages from friends
 Add small thermal printer for hard copy output
 React to commands, e.g. Balance check.
 Other USB devices, e.g. Bluetooth can be used

17. Improvements
 Reposition dongle to outside of board
 Or provide a cutout so USB socket is at correct angle and
copper pour is not shielding dongle
 Use alternative USB socket footprint with plated
mounting holes
 Add sound notification of new messages
 Silkscreen updates and corrections
 Add logos for open hardware and publish CAD files

18. Thank you

19. Featured sites
 mbed.org – Prototype platform
 mbed.org/handbook/Vodafone – Mobile dongle
 www.meetup.com/iotlondon - IoT London Meetup
 www.cadsoftusa.com – Supplier of PCB design tools
 mayhewlabs.com/webGerber – 3D gerber viewer
 www.seeedstudio.com – Fusion PCB service
 ifttt.com – Making the internet do things
 blog.thiseldo.co.uk/?p=703 – my blog with more info