Balloon hardware overview



There are various different flavours of balloon. Both iterations of the design, and different build options. The info on this site currently covers balloon v2.05 and v3.33. Versions prior to 2.05 are not described here in any detail.

Balloon 3.0 Specification

Core Features

I/O and Interfaces


Schematics and an imagemap of the board indexing connectors and datasheets are available for each version on the links above.


Currently there are 2 build options being made - 'CPLD board' and 'FPGA Development board'. Both are available from iEndian. The design allows for further sensible options and feedback from prospective users is of interest to us in order to decide what standard options to make available.

The various build possibilities are described on the Balloon3BuildVariants page.

Hardware Status

See HardwareStatus for details of which bits of IO have been tested, what hardware they are avialable on, and possible further pointers.

Breakout/Programming Board

A fully featured breakout board has been designed for Balloon 3. This is used by a number of people to program Balloon boards in production and act as a development kit for Balloon. Further details can be found here Balloon3Breakout.

Pinouts and connectors

You won't get far before wanting to know which connectors to use for what (both pysical parts and electrical signals). It can be worked out from the schematics but it's hard work, and there have been a few changes over the board versions (Essentially just affecting USB host/OTG).

Connector Pinouts (Openoffice Sheet) lists pinouts for all variants as well as (Farnell) part numbers for the connectors.



Power options

The following solutions are being developed at CUED and builds on some work over the summer of 2005 for Balloon 2.

Assuming a typical current draw of 100-200mA, several solutions are being worked on: two for robotics (12V) (where current draws can peak at around 4A with stalled motors) and one for the PDA (3.7V) being developed. For the robotics projects, the power to the balloon is provided via Chris Jones's daughterboard whereas for the PDA, the balloon is powered directly from the 3.7V

Lead Acid Batteries

Yuasa sealed lead acid batteries were selected for cost-effectiveness and availabilty: they are available in a large range of capacities, dimensions, and weights depending on particular needs. To charge, we have constructed a simple linear charger based around the UC3906 (PDF) chip from TI. The board is capable of charging the battery whilst supplying the system load; a critical design requirement for CUED.

A stripboard prototype has been developed and tested and a PCB (surface mount) version is being designed at the moment.

NiMH Batteries

A custom NiMH battery pack has been constructed by All Batteries to provide 2700mAH at a nominal 12V. A switch-mode charger designed around the LTC4011 (PDF) chip from Linear is currently being developed but, due to its complexity is suffering a number of technical set-backs. Watch this space for further progress.

Li-Ion Batteries

For the PDA, where weight is a major concern, Nokia BL-5C batteries (the type used in the very common 6230i amongst other phones) provide 900mAH at 3.7V. Two of these are being used in parallel to increase the capacity of the power pack; a Nokia desk charger or 6230i phone can be used to charge the system.

Schematics and Manufacturing details

We haven't put up every document for every release, largely because we are not that organised. Some variants only had very short lives. Be careful about which version of a board a document applies to. In general docs that haven't been superceded still apply.

There is now an overall pinout document that covers all versions and supercedes the per-version ones below.

Version 3.33

Version 3.32

Version 3.21

E1 Engineering build

Version 3.01

P1 and P2 Prototypes

USB Breakout board


Connector Locations


The 4-way power and serial connector in the corner of the board is available from Farnell. The details are:

The pinout of it is:

  1. (closest to corner of board) Power (nominally 5V)
  2. TxD
  3. RxD
  4. Ground

More information

If the information you found on this wiki is not enough, please sent us an email to balloon mailing list.


Balloonboard: Hardware (last edited 2016-11-29 11:46:22 by JonathanMcDowell)