OK, so time to take the wraps off the new v0.4 board!

Firstly though, it's worth giving a brief introduction as to what the aim of this board was. Unlike the v0.2->v0.3 update, the v0.4 board isn't necessarily designed to replace the v0.3. In this regard, the most significant difference is that the new board uses a single internal connector in place of the screw terminals on the v0.3. The idea here is that the v0.4 board isn't connected to directly, but plugs into a low cost interface board instead. This interface board might have something as simple as a bunch of screw connectors on it, but the idea is that application specific boards (ie ones that plug directly into existing looms) can be produced quickly and cheaply. As an example of this, one of the first interface boards I produce will be for an NA Miata / MX-5.

The connector itself is an IDC 40, commonly know as an IDE connector, used in the past for IDE harddisks and CD-ROMs. Cables for these are therefore very cheap and easy to get in a variety of lengths. This internal connector is used for all interfaces except the main 12v in, which remains on a screw terminal that needs to be powered directly.

As far as features go, here are the main highlights:

• Electrically identical (with some pin moves) to all features of the v0.3 board, with the exception of the optional EEPROM chip, which has been removed. Component overlap is therefore also very high between the 2 boards, making assembly and kitting simpler.
• An optional DRV8825 (Eg https://www.pololu.com/product/2133) mounting point has been added for running stepper based idle motors
• Dedicated PWM idle and boost outputs. These are minor updates to 2 of the 'spare' outputs from the v0.3 board, attaching them to PWM pins with appropriate frequencies.
• 5 medium current low side switched outputs have been added. These are suitable for driving relays and low power items (Eg an LED) and will be programmable in the future.
• Board size has shrunk by approximately 30cm2! At 100mm x 100mm, the board will now mount nicely in cases such as Hammond Manufacturing's 1455 series (http://www.hammondmfg.com/1455.htm).
• Better grounding and general electrical protection in a number of areas

I will post some more helpful diagrams over the next day or so, but for anyone wishing to take a look, the schematic and PCB artwork is now available on github

Schematic: https://raw.githubusercontent.com/noisy ... _schem.png
PCB: https://raw.githubusercontent.com/noisy ... .4_pcb.png

Once testing is completed (Probably about a month from now, depending on how long these take to arrive), I will look to begin selling them. If anyone has a burning desire to test one of these out, please let me know as I will have a few spares going.