Skip to content

Sun drying emulation controller for biltong and other dried foodstuffs.

License

Notifications You must be signed in to change notification settings

myles-parfeniuk/biltong_board

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 

History

47 Commits
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Repository files navigation

image

About

Sun drying emulation controller for biltong and other dried foodstuffs, based around STM32G070 series controller.
Intended to be used with drying enclosures like biltong-boxes to produce sun-dried foods in non-ideal climates.

Table of Contents

PCBWay Sponsorship

Thank you to PCBWay for reaching out to sponsor this project and provide access to their excellent service.
PCBWay supports the DIY and open source community as well as students with sponsorships and contests frequently.
Show them some love and consider having your next project fabricated by them:

image

Order here today.

This was my second time using PCBWay's service, and just like last time the boards came out perfect with no defects. While assembling the boards at home with a friend, I even had him comment the silk screen and cosmetic qualities of the board were superior to that of domestic fabrication houses he has seen used throughout his professional career.
To be clear, we are talking about a 0.8mm character height, with no smudging or defected labels on any part of the board, amazing!

The manufacturing and shipping time was just as fast as last time, under 2 weeks from gerber files to packages on my doorstep. Their customer service was also top notch. The packages were initially thought to be lost by the postage service, they offered to replace them at no cost; but, thankfully they were found the next day.

Working with PCBWay both on this project and my previous project here has made them my goto fabrication house. The cost to quality ratio ratio provided by their service is by far the best I have encountered. It would take a serious competitor to make me think otherwise.

Below are some photos of the assembled main boards, along with a 3D printed case to protect the HV parts of the board, designed by hwBirdy007. The quality I'm speaking of is evident when viewing, next time I want to try a different color solder mask, as PCBWay provides a wide variety of choices at no extra cost (green ,red, yellow, blue, white , and black).
Note that the bodge wires on Y2 (low speed oscillator for RTC) are not the fault of PCBWay, I used an incorrect schematic symbol leading to an erroneous design, oops. Looks like I'll be using PCBWay again soon. This error has already been corrected in the provided KiCad files and generated gerbers.

image image image image

(back to top)

Hardware

Biltong board is composed of 4 separate PCBs: a main driver board, a UI/control deck board, and 2 identical temperature + humidity sensor breakout boards.

The schematics and layout files for all boards can be found within the hardware directory of this repo, in the form of KiCad 7.0 projects.

The key features of each board:

Main board:

  • Interfaces to drive sensor breakout boards, the control deck board, heat lamps, and +12V PC fans.
  • Stand alone power supply, no DC adapter required.
  • A magnetically isolated current sensor for linearizing the response of the triac based heat-lamp dimmer circuit.
  • A low speed oscillator and coin-cell battery interfaced to STM32's RTC for time keeping during power loss.
  • A normally open safety relay to remove the lamps from circuit.
  • IO expansion header, with unused GPIO for development of new features or debugging.
  • Extra mounting holes for safety cover, to prevent mishaps with high voltage side of board.

UI/control deck board:

  • An SPI based SH1122 driven OLED display for indicating information to the user.
  • 3 navigation buttons for user input.
  • A buzzer to notify user attention is required.

Sensor Breakout Board:

System Block Diagram

image

SIGNAL PIN # GPIO# PERIPHERAL DESCRIPTION
DISP_SCL 12 PA1 SPI1 SH1122 display SPI clock signal.
I2C1_SDA 32 PA10 I2C1 Temp & humidity sensor A I2C data signal.
I2C2_SCL 33 PA11 I2C2 Temp & humidity sensor A I2C clock signal.
I2C2_SDA 34 PA12 I2C2 Temp & humidity sensor B I2C data signal.
DISP_MOSI 13 PA2 SPI1 SH1122 display SPI data signal.
SW_UP 14 PA3 GPIO Active low user up navigation button signal.
SW_ENTER 15 PA4 GPIO Active low user enter/select navigation button signal.
SW_DOWN 16 PA5 GPIO Active low user down navigation button signal.
FAN_B_PWM 17 PA6 TIM16_CH1 or TIM3_CH1 Fan B PWM signal.
FAN_B_TACH 18 PA7 GPIO or TIM17_CH1 or TIM14_CH1 Fan B tachometer signal.
I2C1_SCL 29 PA9 I2C1 Temp & humidity sensor B I2C clock signal.
FAN_A_TACH 19 PB0 GPIO or TIM3_CH3 Fan A tachometer signal.
FAN_A_PWM 20 PB1 TIM14_CH1 Fan A PWM signal.
UART_TX 22 PB10 USART3 Serial console UART TX signal for development.
UART_RX 23 PB11 USART3 Serial console UART RX signal for development.
I_SENSE 21 PB2 ADC_IN10 Heat lamp current sensor output, analog signal from 0 -> vcc/2 (0A) ->vcc.
ZERO_CROSS 40 PD2 GPIO Live/mains signal for sine wave zero cross detection (triac shut off point).
BUZZ 45 PB6 GPIO or TIM1_CH3 or TIM16_CH1N Buzzer alarm signal, frequency modulated PWM.
DISP_CS 46 PB7 GPIO SH1122 display SPI chip select signal.
DISP_DC 47 PB8 GPIO SH1122 display data/!command signal, held low for data, high for commands.
DISP_RES 48 PB9 GPIO SH1122 display reset signal.
TRIAC_TRIG 42 PB3 GPIO Triac dimmer trigger, single pulse enables triac until instantaneous AC voltage crosses 0V.
HEAT_LAMP_EN 43 PB4 GPIO Normally open heat lamp saftey relay enable. When held high heat lamp circuit is closed.

(back to top)

PCB Renders

Main Board

image image

Control Deck Board

image image

Sensor Breakout Board

See myles-parfeniuk/wsen_hids_breakout.

(back to top)

Layout

Main Board

image

Control Deck Board

image

Sensor Breakout Board

See myles-parfeniuk/wsen_hids_breakout.

(back to top)

Schematics

Main Board

Alt text

Alt text

Alt text

Control Deck Board

Alt text

Sensor Breakout Board

See myles-parfeniuk/wsen_hids_breakout.

(back to top)

Firmware

The firmware is currently being developed. This repo will updated as work is completed.

(back to top)

License

Distributed under the GPL-3.0 License. See LICENSE.md for more information.

(back to top)

Contact

Myles Parfeniuk - myles.parfenyuk@gmail.com

Project Link: myles-parfeniuk/biltong_board

(back to top)