PiSteer

Autosteer controller.

Warning

This just just for demonstration and proof of concept. This should never ever be used on full sized machinery. You will crash and die if You do. You have been warned.

Other documents

Pictures and something here.

Raspberry Pi 3

Why Raspberry Pi? It's just somethin I had laying around.

install

Configure raspberry:

sudo raspi-config

From System Options set Wireless LAN, from Interface Options enable I2C, disable login console on serial port, enable serial port hardware.

Edit /boot/firmware/config.txt

sudo nano /boot/firmware/config.txt

Add the line dtoverlay=pwm,pin=12,func=4 Save the file and reboot.

wget https://github.com/salmiac/pi-steer/releases/download/v0.1.5/pi-steer-rust
chmod +x pi-steer-rust

Run it once and default settings file (settings.json) is created. Edit file.

nano settings.json

To build binaries Yourself look here

Raspberry Pi Pico W

Is used as standalone IMU. README.md

If GPS is connected to Raspberry Pi serial port, there is just not enough IO-pins for IMU.

Raspberry Pi pinout

Device	pin	Pi GPIO	Pi pin	Pi pin	Pi GPIO	pin	Device
BSS138, BNO055, BNO085 VCC/PS0	LV, VIN	3v3 Power	1	2	5V Power	HV, VDD	BSS138, ADS1115
BSS138 (ADS1115), BNO055	A2, SDA	I2C SDA	3	4	5V Power	VCC, 1-A	RTY120LVNAA
BSS138 (ADS1115), BNO055	A1, SCL	I2C SCL	5	6	Ground	GND, 2-B	RTY120LVNAA
Relay	1	GPIO 4	7	8	GPIO 14	TXD	BNO085 SCL/SCK/RX
BNO055	GND	Ground	9	10	GPIO 15	RXD	BNO085 S/MISO/TX
Relay	2	GPIO 17	11	12	GPIO 18	2	Manual (in)
Autosteer switch	A	GPIO 27	13	14	Ground	GND	Relay
Relay	3	GPIO 22	15	16	GPIO 23	3	Manual (in)
LED:s	+	3v3 Power	17	18	GPIO 24	4	Manual (in)
Relay	4	GPIO 10	19	20	Ground	-	Power LED
Relay	5	GPIO 9	21	22	GPIO 25	5	Manual (in)
Relay	6	GPIO 11	23	24	GPIO 8	14	Relay
Autosteer switch	B	Ground	25	26	GPIO 7	13	Relay
Relay	7	GPIO 0	27	28	GPIO 1	12	Relay
Relay	8	GPIO 5	29	30	Ground	GND	BSS138
Relay	9	GPIO 6	31	32	GPIO 12, PWM 0	PWM	Cytron
Work switch		GPIO 13	33	34	Ground	GND	Cytron
Relay, manual mode	2	GPIO 19	35	36	GPIO 16	DIR	Cytron
Manual (in)	1	GPIO 26	37	38	GPIO 20	11	Relay
Relay mode switch	GND	Ground	39	40	GPIO 21	10	Relay

Wheel angle sensor RTY120LVNAA

Function	pin
Vcc 5V	1-A
GND	2-B
output	3-C

Adafruit ADS1115 4-Channel ADC and 4-channel I2C-safe Bi-directional Logic Level Converter - BSS138

Wires connectedd to raspberry Pi via level converter

GPIO	Pi pin number	BSS138
3v3 Power	1	LV
5V Power	2	HV
I2C1 SDA	3	A1
I2C1 SCL	5	A2
Ground	7	GND

GPIO	Pi pin number	ADS1115	BSS138	RTY120LVNAA
5V Power	4		VIN	1-A
		SDA	B1
		SCL	B2
Ground	20	GND	GND	2-B
		A0		3-C

Inertial masurement unit (IMU)

BNO085

BNO085 is connected by serial. It uses xxxx-RCV mode.

Wires connected to raspberry Pi.

GPIO	Pi pin number	BNO085
3v3 Power	1	VIN
I2C1 SDA	XX	SDA
I2C1 SCL	XX	SCL
Ground	9	GND
PC0	9	GND

https://learn.adafruit.com/adafruit-9-dof-orientation-imu-fusion-breakout-bno085

https://www.ceva-dsp.com/wp-content/uploads/2019/10/BNO080_085-Datasheet.pdf

Motor controller Cytron MD13S

https://docs.google.com/document/d/1icu1GVDxZhUn3ADSUc3JknNcmUMdPcsnJ4MhxOPRo-I/view

Motor controller wiring

GPIO	Pi pin number	Cytron
Ground	6	GND
GPIO 12, PWM0	32	PWM
GPIO 25	22	DIR

Autosteer switch

A microswitch to activate autosteer is connected to Raspberry Pi:

GPIO	Pi pin number	switch
Ground	30	A
GPIO 27	13	B

Relays

Pololu Basic 2-Channel SPDT Relay Carrier with 12VDC Relays https://www.pololu.com/product/2485

GPIO	Pi pin number	relay	12V	Output
GND	14	GND
		GND	GND	Out GND
		VDD	+12 V
GPIO 4	7	EN1
GPIO 17	11	EN2
		NO1		Output Up
		NO2		Output Down

Section control

There are 3 different modes for sections control.

• Impulse. 'impulse' is default 3 seconds. I use it for pneumatic cylinder to controld hydraulic lever. One GPIO pin for up and one for down motion.
• OnOff. It is just for on-off relays. I don't actually use it anywhere.
• Reverse. This uses a pair of GPIO pins and relays to reverse the polarity of voltage, e.g. 'On' is +12 V and 'Off' is -12 V. Sprayer sections control uses this one.

Sprayer control

Sprayer pressure controller is separate feature from AgOpenGPS. Software on Raspberry Pi takes care of sprayer pressure reading and pressure control. One GPIO pin is also used to monitor whether boom is on locked position. Two GPIO pins (relays) are used to control pressure valve. There are two options for pressure control, constant pressure and speed-based variable pressure.

In my setup, this controller replaces controller for my Amazon sprayer.

Other (Windows) software is used to monitor sprayer pressure and to control settings. https://github.com/salmiac/salmiac-sprayer Software has settings screen for nozzle spacing, nozzle size selector, litres/ha, min pressure, max pressure and nominal pressure. Nominal pressure is used for constant pressure. Second screeen to monitor target pressure, current pressure and speed. Buttons for controller on/off and button to select variable or constant pressure. Also indicators for min and max speed for selected pressure range, indicator for boom locker yes/no and selected nozzle size.