MiniPiio DIO16 v0.10

June 24, 2012

** UPDATE: You can get these boards at tindie.com in the DTronixs store

The third and final board we built from the batch of PCB’s we received on Friday was the MiniPiio_DIO16.

The MiniPiio_DIO16 is a 16-channel digital input/output add-on card for the Raspberry Pi. The board can use either a Microchip MCP23s17 (SPI) or a MCp23017 (I2C) Port Expander IC.

The choice of chip is done by jumper headers on the PCB. In addition the I2C and SPI address is also selectable by jumper headers. Finally, the choice of SPI Chip Select (SPI_CE0 or SPI_CE1) can ne made via a jumper header. By my reckoning thats 7 jumper headers.

The I/O ports from the chis are brought out to two pin strips. As well as I/O each pin strip has a ground, while one has a fused 5V supply and the other a non-fused 3.3V supply.

The schematics are here


MiniPiio ULN2803 v0.10

June 24, 2012

** UPDATE: You can get these boards at tindie.com in the DTronixs store

The second board we built over the weekend was the MiniPiio_ULN2803. From its name you can guess it’s a printed circuit board with a ULN2803 8-channel Darlington driver. The ULN2803 allows us to drive cicuits with significantly higher current (up to mA) then we could with just the Raspberry Pi GPIO pins alone. The GPIO Pins are connected to ULN2803 inputs, with the its outputs going to an array of strip headers laid out as servo pins.


The board design was done in Design Spark PCB and a PDF for the schematics is here.


MiniPiio RS232 v0.10

June 24, 2012

** UPDATE: You can get these boards at tindie.com in the DTronixs store

As promised we spent our weekend building the other MiniPiio designs. So without any further ado, here’s the MiniPiio_RS232.

This is for anyone who wants a RS232 port on the Raspberry Pi but doesn’t want to give up one of the two precious USB ports or clutter their desk with a USB hub to use a USB to RS232 adapter.

Unfortunately, there’s a mistake in the dimensions of the PCB. Instead of being 50 x 40mm like the other MiniPiio’s, the MiniPiio_RS232 is 45 x 42mm so its wider and shorter than the others. Being shorter is not a problem just ask Napoleon, but being wider does mean it interferes with the RCA Composite Video connector. 30-seconds with a file cuts it down to size but it does mean back to the drawing board or rather Design Spark PCB.

It was easy to fix, but just means another trip to the PCB manufacturer for another batch of boards. A PDF for the schematics is here.