Overview

RPI and NRF for industrial application : The board has 2 modes :

• RPI + NRF : RPI handles all the Features below, and you can add an NRF for extra real time event handling.
• NRF only : The NRF handles all the features below. You can use it with BLE or RF24. It is compatible with MYSENSORS also.

Supply voltage up to 24v

All the features has been tested

Github : https://github.com/DeltaIC/Utilipi

Openhardware.io : https://www.openhardware.io/view/618/UtiliPi

Features

IO EXTENDER

There is 32 channels I/O included 16 which can work with interrupt service thank to an I/O expender on I²C bus.

ADC

The Analog to Digital Converter have 4 channel 10V max and 4 channel with input selection. The input selection works either for 10V max or 4-20mA loop.

SPI, I²C and UART

For each protocol, the connectors are routed to their native port on the raspberry. The level input can be 16V max. For the SPI, 4 channel from the raspberry are used for CS for each connector.

Transistors NPN

There is 8 transistors NPN, the collector and emitter pin are available on the connector. For each transistors, a LED show it state (open/close).

GPIO

There is 4 channel directly connected to the raspberry. Unlike the others, they are not protected for over-voltage (max 3.3V).

POWER

The board can be powered by raspberry (remove the jumper JP1) or it can be powered by external supply (max 36V). This module also works : https://fr.aliexpress.com/item/mini-DC-DC-Converter-Step-Down-buck-Power-Supply-Module-for-Flight-Control-Car/2038556858.html?spm=a2g0s.9042311.0.0.5bf36c37EOK96X

BLOG

• 22/08/2018 : Ordering the first board at a PCB manufacturer (JLCPCB)
• 28/08/2018 : The 5 board ordered are arrived, but there is 3 copper areas missing due to editor which don't make good gerber file. Issue post on the user forum. [https://easyeda.com/forum/topic/Copper-area-overlap-bug-deaf372a8630482aa5ac4a56d1aa59e7]
• Testing the board and the routing feature by feature
• 07/09/2018 : I²C adaptateur and IO extender has been soldered, the raspberry succed in discovering slave in the bus. Good point.
• 28/09/2018 : The hole size for connector is too thin, and routage will be update for allowing SPI without using IO extender.
• 30/10/2018 : The transistors, the IOExtender, the I2C and SPI voltage shift works well.
• 31/10/2018 : I've redesign the board according to the mistake i've found. Also, a library from ABElectronic use the IOextender and ease it use. [https://github.com/abelectronicsuk/ABElectronics_Python_Libraries/tree/master/IOPi]
• 25/02/2019 : Add the Github, multiple corrections in the PCB incoming with v2.2
• 28/02/2019 : New version 2.2, add the source code on github
• 29/04/2019 : New version 2.3, add the source code on github. Add the nrf52 to the board.

TO DO

• Change the NRF used (to small and need for external antenna connector)
• Change 3V3 supply voltage
• modify solder pad of the io extender (a little small)
• Replace jumper for the ADC
• correct minor bug (Silkscreen)