Project Logs

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• LRMS MPPT Solar Power Module - Test and Characterization

  jstuart • 09/25/2022 at 03:34 • 0 comments

  
  R1  used with a INA3221 voltage and current monitor as a prototype model for revision 2. 
  

  Prototype for revision 2:
  

  Weather conditions:

  2022/09/22 : Sunny with occasional high thin clouds

  2022/09/23 : Early morning thin overcast followed Sun with intermittent cloud coverage

  Solar Panel Configuration:
  

  Orientation: South

  Latitude: 48°4’41”N

  Panel Angle: 50 degrees

  Panel Width: 221mm

  Panel Length :257mm

  MPPT Solar Power Module:
  

  Battery : 2500mAh 3.7V LiPO 1S cell

  MPPT Charge Current : 200 mA

  Charge Control Termination: C/10

  MPPT LiPO Cell maximum charge level : 4.15V

  Boost Converter Efficiency :

  3.3 Vin 6.0 Vout I_Load 10mA 80 percent
  

  3.3 Vin 6.0 Vout I_Load 200mA 85 percent

  4.2Vin 6.0 Vout I_Load 200mA 80> percent

  4.2Vin 6.0 Vout I_Load 200mA 90> percent

  Load Current : 20mA

  V_Batt Load Voltage : 5.832V

  
  

  Solar Panel : Voltaic Systems P109 6Volt 9 Watt
  

  Panel Ratings		Nominal	Expected
  Open-Circuit Voltage	Voc	7.67	7.28	V
  Voltage at Max Power	Vp	6.50	6.18	V
  Short-Circuit Current	Isc	1.56	1.50	A
  Current at Max Power	Ip	1.46	1.39	A
  Maximum Power	Wp	9.49	8.56	W

  
  

  
  

  
  

  2022-09-23 07:20:50 : Battery level 3.872 V

  2022-09-23 10:10:24 : 4.144 V

• LRMS Analog IO Board - R1

  jstuart • 09/12/2022 at 23:36 • 0 comments

  The LRMS analog I/O board is intended for analog sensors or custom sensor designs that do not have digital interfaces. In addition to the analog I/O the  board also supports I2C and TTL UART connections.

  A high speed amplifier with a sample and hold peak detector with a DC boost converter has been included for photo detectors such as a silicon photo-multiplier.

  Board Connectors:
  

  J1 & J2 : Two Configurable nano power operational amplifiers, can be configured as Differential, Single ended Non-Inverting/Inverting. Each amplifier output  is buffered with a unity gain amplifier to the ADC channels.
  

  (6Kz unity gain, 350nA per channel)
  

  J3 : One high speed non-inverting operational amplifier with sample and hold peak detector.

  (250Mhz unity gain, 100Mhz GBW)
  

  J8: DC boost converter up to 32 volts DC.
  

  J6 & J7 : I2C bus interface connectors

  J5 : RS-232 TTL UART Connector
  

• LRMS Monitoring Station R1 - Operating Status 8/19/2022

  jstuart • 08/19/2022 at 22:11 • 0 comments

  Revision 1 of the LRMS monitoring station has been continuously operating outdoors for 8 months beginning January 2022. The sensors for the station are the usual temperature and humidity sensors found on many projects but I added a UV sensor to make the R1 station more unique and test the hardware and software.
  

  Here are a couple of screen shots showing the data collected from LRMS R1

  The sensors used are a DS18B20 temperature probe, Si7021 temperature and humidity sensor, and a LTR390 UV sensor in a PVC T pipe fitting.
  

  UV & Humidity Sensor Module
  

  The UV sensor has a 20mm x 20mm fused silica window epoxied in front of the LTR390 sensor (right side of photo)
  to protect from weather and for maximum transmission of UV to sensor.
  

  The Si7021 located inside of PVC L fitting.

  The DS18B20 is a water proof module and is shielded from direct solar exposure with a PVC pipe section.
  
  
  

  March 15 2022 14:50PST
  

  August 05 2022 14:19 PDT
  

• LRMS Revision 2 PCBs - Initial Route Complete

  jstuart • 08/17/2022 at 23:00 • 0 comments

  Initial PCB routing is competed and I am working cleaning up traces and adding text to silkscreen for headers etc.

  All three boards pass design rules checks.

  LRMS  LoRa Transceiver R2

  LRMS LoRa Gas Sensor R2

  MPPT Solar Power Module R2

• LRMS Revision 2 PCBs - 3D models

  jstuart • 08/11/2022 at 23:19 • 0 comments

  I have been working on revision 2 of the LRMS boards. Component placement is completed and I will be routing 
  Transceiver and gas sensor boards.
  

  • All  board dimensions have been updated to 90mm x 70mm (LxW). This supports inexpensive 70mmx90mm prototyping boards.
  • Connectors have been changed to 2x10 row connectors and aligned on 2.54mm spacing from board edges.
  • Added a new board - LRMS Environmental Gas Sensor. This a design based on my original Rev 1  test board.

  LRMS LoRa Transceiver R2

  Revision 2 :
  

  • uSD card connector for data logging

  • JST connector for connection to LRMS MPPT Solar Power Module

  • Reverse power  polarity protection

  LRMS Environmental Gas Sensor

  • Spec Sensors Electrochemical gas sensor array

  • 3.0V Lithium Cell or 3.0V LDO regulator

  •  Ultra low power op-amps for
  • I2C bus connector
  • UART connector

  LRMS MPPT Solar Power Module

  • J7 & J8 JST connectors changed to 5 pins. J7 is for I2C bus interface and J8 is for INA3221 status.

• Update to LoRa_RMS on GitHub

  jstuart • 08/03/2022 at 19:06 • 0 comments

  LoRa_RMS on Github has been updated to include initial release of code and installation instructions.  See Software directory for details. LoRa_RMS is the directory for the system.
  

• Design files now on Github

  jstuart • 08/02/2022 at 22:43 • 0 comments

  The design files for the LoRa Remote Monitoring system are now on GitHub.
  

  I am in the process of working on revision 2 of the PCB board set and documentation.

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