Prototype handheld display

I've been working on a custom PCB for sometime now and finally have something to show, I'm using this as a way to document my progress. Let me just say that it's been some fifteen years since I last designed a PCB and I'm a software engineer by trade (well so people would have me believe) :

mbed website

The PCB above is of my own design using the LPC1768 as the MCU an FTDIRS323 to USB converter and a small amount of I2C memory for parameter storage. I designed the PCB using information from the reference design and layed it out using the Eagle PCB design software. The board was manufactured/assembled by PCBTrain.

Eagle schematic of the minimum parts of the reference design I needed to get started (right click and choose save as) /media/uploads/ScubaBoy/basicreference.sch

The main purpose of the PCB is to drive a TFT display. You will see that I'm using my development mbed as the programmer.

Progress to date:

  • Able to program the MCU.
  • Verified RS232 to USB converter works correctly.
  • Verified control pins are correct.

Revision 2 of the board arrived yesterday (Newbury Electronics have done a cracking job again) number of improvements over the initial design.


Whats new:

  • Micro SD card socket for storage,
  • Single cell lithium ion battery buck boost and charging circuit (top right)
  • Battery backup for RTC.


  • Reduced board size.

Items yet to be added/removed:

  • Mbed drag and drop programming interface.
  • Remove ISP programming connector.

Latest update of the board with the mbed interface :) /media/uploads/ScubaBoy/wp_20131215_004.jpg

and TFT display mounted /media/uploads/ScubaBoy/wp_20131214_001.jpg

Mbed enabled display board schematic /media/uploads/ScubaBoy/example.pdf


5 comments on Prototype handheld display:

26 Jul 2013

This looks really cool. What LCD are you using?

26 Jul 2013

The display is the TFT Proto, I originally designed the PCB for the new version of the display but the one I got from a UK supplier was the previous one. So had to make a wire loom to connect it up. Was planning to redesign the PCB so not a problem still have battery management components to add.

08 Jan 2014


Can I ask how much it cost for the assembled PCB from Newbury?



08 Jan 2014

Paul Chilton wrote:


Can I ask how much it cost for the assembled PCB from Newbury?



For a UK based PCB manufacture the prices are very good, the PCB costs £232 fully populated and tested.

06 May 2014

sir can u share the test circuit that is required to use lpc1768 with its programming connection to test with led on off

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