Description of System - Bot Electrical[edit | edit source]

The electrical system of the Growbot platform is controlled by a Raspberry Pi 4 and is separated into power distribution, drive train controls, and sensor controls. Power distribution consists of a single 6s LiPo 22.2V Battery that powers a nominal voltage rail with the O-Drive Motor Control Board attached and by extension, the Turnigy Outrunning Motors. Between the nominal rail and the O-Drive Motor Control Board is an Emergency Stop system that utilizes an automotive relay to cut power from reaching the control board. Additionally, the battery has a voltage sensor attached to it that will monitor the battery and be able to alert the raspberry pi (through the ADC) of the decreasing battery level throughout use. That 22.2V battery is then stepped down to 5V control power using a 5V regulator and is brought to a set of rails. These rails power the Raspberry Pi 4, the Analog to Digital Converter, and the rest of the sensors on the Growbot platform. Drive train controls consist of the Motor Control Board and Turnigy Outrunning Motor setup. These motors are controlled by the control board which receives its commands from the Raspberry Pi 4. Sensor controls consist of all of the sensors and the sensor-related electronics of the Growbot platform, with the exclusion of the voltage sensor.

Procedure - Main Electronics Board[edit | edit source]

Materials
Description Count
Raspberry Pi 4 1
O-Drive Control Board 1
50W Power Resistor 1
6s LiPo 22.2V Battery 1
Voltage Sensor 1
5V Regulator 1
Analog to Digital Converter 1
Large Power Rail (for 24V) 1
Small Power Rail (for 5V/GND) 2
Automotive Relay 1
Relay Holder 1
M2.5x10 Screws 14
M3 Nylon Standoffs 4
M4x10 Screws 2
M5x10 Screws 2

Tools[edit | edit source]

  • M2.5 Allen Wrench
  • M4 Allen Wrench
  • M5 Allen Wrench

Procedure[edit | edit source]

  1. Layout the following electrical components on the main electronics board keeping systems together (ie. power distribution, drive train, sensors). Make sure that there is enough room for all of these components and there is room for the necessary wiring.
    1. Battery mount
    2. Relay Mount
    3. Rails (x3)
    4. O-Drive Motor Control Board
    5. 50W Power Resistor
    6. Raspberry Pi 4
    7. 5V Regulator
    8. Voltage Sensor
  2. OSHE Growbot Electrical Board.jpeg
    Secure the components listed above to the main electronics board using M3 Nylon Standoffs for the O-Drive Motor Control Board (x4), M5x10 screws for the 5V Regulator (x2), M4x10 screws for the largest rail (x2), and M2.5x10 screws for the rest of the components (x14).
  3. Place the battery and relay into their appropriate mounts.

Procedure - Soil Sensor Mechanism[edit | edit source]

  This probing mechanism uses a NEMA11 stepper motor to drive a rack with the sensor on the end. This mechanism can easily be adapted for any sensor that needs to be probed.
Soil Mechanism Materials
Description Count
M3 Heat Insert 3
3030 L-bracket 1
M6x15mm 1
M4 3030 T-nut 1
M4x16mm 1
NEMA11 Motor 1
M2.5x6mm 4
M3 Hex Nut 3
M3x5mm Set Screw 1
M3x10mm 2
M2.5x10mm 4
M2.5 Hex Nut 4
Stemma Soil Sensor 1
M3x12mm 2
M3x16mm 1
Tools
Soldering Iron
  1. OSHE Growbot Soil Mount.jpg
    StepperMount will need two M3 heat inserts installed. Using the 72mmMeasureBlock and 3030 L-bracket, attach the StepperMount to the 3030 rail. You will also need M4x16 and M4 Tnut to attach the StepperMount.
  2. OSHE Growbot Soil Motor.jpg
    Using four M2.5x6 bolts attach the NEMA11 motor to the MouterMount.
  3. OSHE Growbot Soil Panel.jpg
    Place external front panel onto bot.
  4. OSHE Growbot Soil NutInsert.jpg
    Insert three M3 nuts into SensorRackTrack.
  5. OSHE Growbot Soil RackBearing.jpg
    Place Bearing into cylindrical cutout of SensorRackTrack. Attach with two M3x12 bolts.
  6. OSHE Growbot Soil PinHold.jpg
    Install M3 heat insert. Attach PinionGear with M3 setscrew. Attach SensorRackTrack with two M3x10 bolts.
  7. OSHE Growbot Soil RackNut.jpg
    Insert four M2.5 nuts into SensorRack.
  8. OSHE Growbot Soil SensorMounting.jpg
    Place Stemma Soil Sensor into SensorRack.
  9. OSHE Growbot Soil SensorCover.jpg
    Cover the sensor with the two piece cover, Top Cap and Bottom Cap, with four M2.5x10 bolts.
  10. OSHE Growbot Soil Rack.jpg
    Insert the SensorRackAssembly into the SensorRackTrack.
  11. OSHE Growbot Soil Final.jpg
    Attach SensorRackCover with a M3x16 bolt.

Procedure - Ambient Sensors[edit | edit source]

Materials
Description Count
9-Degrees-of-Freedom Sensor 1
Webcam 1
Temperature and Humidity Sensor 1

Description of System - Base Electrical[edit | edit source]

The electrical system of the Charging Base consists of a 12VDC power supply, a switch box, charging prongs, IR sensors, an Arduino and a 5V relay. The 12VDC power supply is externally powered by a standard IEC 320 C13 power cable from a standard 120VAC 15A outlet. The receptacle is located on the switch box on the front of the base, which also features an AC SPST switch to cut power at the AC line connection. The switch box also features two additional DC switches; one for manually cutting power to the charging prongs, and one for manually cutting power to the inductive wire. The interior of the switch box also houses an Arduino Mega 2560 and a 5V relay which cut power to the charging prongs when the bot is not stationed inside the charging base. This detection is achieved by using an IR through beam sensor, with the emitter and collector being located on opposite sides of the charging base.

Procedure - Charging Base[edit | edit source]

Materials
Description Count
Arduino Nano V3 1
5V Relay 1
Switch Box 1
DC SPDT Switch 2
AC SPST Switch 1
12VDC Power Supply 1
Power Supply Mount 2
IR Through Beam Sensor 1
M4x10 Screws 4
12-25VDC Boost Converter 1
Tools
M4 Allen Wrench
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