RASPBERRY INTERFACE BOARD FCALLBOX

Description

This interface board for Raspberry PI, implement the functions following :

- Powered input 12V with DC/DC 5V 3A switchable to put the Raspberry in standby.
- Smart ON/OFF circuit with push button (managed by a PIC 16LF1824).
- Connectors to interface the Raspberry with rotary encoder / buttons.
- Can take place between the Raspberry and a TFT display via connector GPIO 40 points.
- output 12V commuted by the PIC to power others systems.


This board is used in the FCALLBOX measurement system described here

Summary

• Schematic

• Bill of material

• PCB

• Assembly

• Modification

• Soft implementation

Schematic

Download here the schematic

Bill of material

Top view C9,C10,C11 Capacitor 22uF 10V 10% X5R 0603 All brand C15,C16 Capacitor 10uF 16V 10% X5R 0603 All brand C1 Capacitor 22uF 25V 10% X5R 1210 All brand C2,C17,C3,C4,C5 Capacitor 100nF 50V 10% X7R 0603 All brand R14,R21 Resistor 1K 5% 0603 All brand R7 Resistor 7.5K 1% 0603 All brand R8 Resistor 40.2K 1% 0603 All brand R12,R15,R2,R5,R16,R17,R18,R19,R20,R13,R22,R23,R24,R25 Resistor 10K 5% 0603 All brand R1 Resistor 22R 5% 0603 All brand R3 Resistor 75KR 1% 0603 All brand R4 Resistor 20KR 5% 0603 All brand R11 Resistor 100KR 5% 0603 All brand L1 inductor 4.7uH 6A 7x7 BOURNS SRP6540-4R7M or equivalent U3 IC LDO 3.3V 800mA SOT223-4 LM1117IMPX-3.3/NOPB Texas Instruments U2 IC PIC16LF1824 SOIC14 Microchip PIC16LF1824-I/SL U1 IC MP2315 SOT23-8 MPS (Monolithic Power System) / MP2315GJ Q1 transistor BC846 STO23 All brand D1 Diode BAS16 All brand RL1 Relay 2RT 12V TYCO / V23105A5003A201 or equivalent J3 Connector male 1x6 pitch 2.54mm All brand J5 Connector male 2x20 pitch 2.54mm h=11mm ESW-120-12-T-D or equivalent ??? J2,J4 connector 2 points pitch 5.08mm WEIDMULLER 1760490000 or equivalent

Bottom view J6 connector femal 2x20 pitch 2.54mm All brand

PCB

This PCB F00116 2 layers has 80x50mm dimensions.

Download here the PCB files

Assembly

Top view

Download here the assembly drawing in png (with the values of the components)      
Download here the assembly drawing in pdf (without the values of the components)      

pictures

Modification

U3 must be isolated as below :

Soft implementation

The functions are :

• Power ON :

Led is light ON.

System is powered ON.

• Pushing the button during more than 1s and less than 5s :

The led blinks 5 times by second.

The PIC send a command to the Raspberry (GPIO17) to inform it to go in halt.

The PIC wait for Raspberry to confirm the halt (GPIO4 0V).

The PIC lights OFF the LED and cut the 12Vc which powers OFF the Raspberry.

• Pushing the button during more than 5s :

The PIC lights OFF the LED and cut the 12Vc which powers OFF the Raspberry.

• Pushing the button during more than 1s and less than 5s during the system is OFF :

The PIC lights ON the LED and set the 12Vc which powers ON the Raspberry

Download here the hex file to programm the PIC      

Download here the projet with its sources compiled under MPLAB XIDE v5.10