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1 |
| -# Concept change |
2 |
| -- Enclosure change: 1455K1202 (120x78x43 space for DGNSS) or 1455J1201 (120x78x27 for single GNSS) |
3 |
| -- Replace HM-19 Bluetoothmodule with a ESP32-WROOM-32U with external Antenna. Could even be used to flash the STM32F4 via WIFI. Connect STM32 UART, Boot-0 and Reset for Wifi flashing option. Attention: 400mA peak consumption in Wifi Mode. Example for WIFI / TCP: https://github.com/AlphaLima/ESP32-Serial-Bridge Connection of two smartphones simultaneously in a double seater is possible. |
4 |
| -- Design milled static pressure hose connector. Concept Idea: Mounting holes 4x in 11.5mm distance square on the edge so that inner hoses are only required for pitot sensing? |
5 |
| -- U.FL for GNSS and Wifi/BT via external SMA-Pigtails. |
6 |
| -- USB-C connectors whereever possible. Vertical USB-C for GNSS somewhere on PCB |
7 |
| -- 2 RJ45 connectors. 1 for CAN/RS232 (selectable) 1 for RS232 |
8 |
| -- Redesigned 3.3VA supply with capacity multiplier and filtering. |
9 |
| - |
10 |
| -# TODOs Version 2.0 |
11 |
| -- Finished! |
12 |
| - |
13 |
| -## Done |
14 |
| -- DONE: Larus Symbol on PCB |
15 |
| -- DONE: Separate Shield GND around the PCB connected with one ferrit to GND. |
16 |
| -- DONE: Thermal reliefs on copper fills. |
17 |
| -- DONE: Added 3 mounting holes 0.8inch distance for sparkfun headers |
18 |
| -- DONE: MS5611 no routing not between pins! |
19 |
| -- DONE: Active current limiting of GNSS antenna feed with C8542 cuircuit taken from https://content.u-blox.com/sites/default/files/ZED-F9P_IntegrationManual_UBX-18010802.pdf |
20 |
| -- DONE: Added a LED to 3.3VA |
21 |
| -- DONE: ESD-diodes at voltage supply input and GNSS antenna. |
22 |
| -- DONE: changed ptc fuse with a suitable current |
23 |
| -- DONE: Change RJ45 CAN pinout so that a real twisted pair is used. |
24 |
| -- DONE: Replace the diodes with a lower forward voltage ones. |
25 |
| -- DONE: Boost Converter to Boost USB Voltage: TPS61170DRVR Inductors: 10uH 1.5A: C340393, |
26 |
| -- DONE: Move sd-card as far as possible to the pcb edge. |
27 |
| -- DONE: Redesign 3.3VA voltage supply with a separate LDO after the 5V Buck. |
28 |
| -- DONE: Filter C for R1 on DC-DC regulators: 15PF here: https://www.researchgate.net/figure/The-circuit-structure-of-the-MP2359-power-supply_fig24_330912026 Put a 0603 footprint. |
29 |
| -- DONE: Check ferrit bead current rating. Saturation! |
30 |
| -- DONE: Remove cheap Gyro / ACC IMU as there will e.g. be a SparkFun 9DoF IMU Breakout. Keep expensive xSense Footprint. |
31 |
| -- DONE: Add a switch for boot0 at the pcb edge. |
32 |
| -- DONE: Add GNSS reset pullup resistor. |
33 |
| -- DONE: At least add a 10uF, 100nF on voltage input and after buck converters. |
34 |
| -- DONE: Change name in schematic for gauge sensor to HSCMRRV001PG2A3 |
35 |
| -- DONE: Replace existing USART-3 connector with Pixhawk standard JST-GH 6 pin Connector to connect and supply simpleRTK2B+heading modules. 1: 5V_IN, 2: RX (3.3V level), 3: TX (3.3V level), 4,5: Not connected, 6: GND |
36 |
| -- DONE: Detect hardware version with an adc input. Might use new GNSS-Reset or CAN2 pullup? Check for missing GPS_RESET pullup to detect the first or newer version. Use ADC123_IN11 to distinguish between 2nd and future versions. 50% for 2nd version. |
37 |
| -- DONE: Decrease testpoint size to 1mm |
38 |
| -- DONE: Sense supply voltage before ferit. |
39 |
| -- DONE: Remove one MS5611 sensor |
40 |
| -- DONE: change RJ45 connectors |
41 |
| -- DONE: u.fl connector |
42 |
| -- DONE: status led name labeling |
43 |
| -- DONE: Connect differential pressure supply to analog voltage and beautify schematic symbol. |
44 |
| -- DONE: Connect USB, RJ45 schields and aluminium enclosure together (Shield_GND). Connect Shield_GND with ferrit to GND. |
45 |
| -- DONE: Connect aluminium enclosure on one side to the PCB. |
46 |
| -- DONE: 7x C77096 (4.7u 1206 Package) on the input side of the Buck Converter. Remove 10uF and 22uF. |
47 |
| -- DONE: Adjust R28 1k 5V Supply LED resistor. |
48 |
| -- DONE: Add ESP protection for CH340E USB connection |
49 |
| -- DONE: Add solder jumper (default closed) on CH340 TXD pin. (Default shall be the USB connection) |
50 |
| -- DONE: GNSS antenna connection on pcb is slightly above the critical length: https://www.youtube.com/watch?v=_Hfzq1QES-Q Consider when changing to U.FL |
51 |
| - |
52 |
| - |
53 |
| -# Design decisions which wont be realized for version 2: |
| 1 | +# PCB Concept |
| 2 | +- Format to fit aluminium enclosure: 1455K1202 (120x78x43 space for DGNSS) or 1455J1201 (120x78x27 for single GNSS) |
| 3 | +- ESP32-WROOM-32U for an improve connectivity. Could also be used to flash the STM32F4 via WIFI. Example for WIFI / TCP: https://github.com/AlphaLima/ESP32-Serial-Bridge connection. Simultaneously two smartphone connections in a double seater are possible via wifi. |
| 4 | +- Footprint for a milled 5mm pressure hose connector on the edge. |
| 5 | +- U.FL connectors for GNSS and Wifi/BT antennas via external SMA-Pigtails. |
| 6 | +- USB-C connectors for GNSS, ESP32 and STM32 |
| 7 | +- 2 RJ45 connectors for CAN and RS232 |
| 8 | + |
| 9 | +# Changes done for Version 2.0 |
| 10 | +- Changed the pcb format to fit the aluminium enclosure 1455K1202 or 1455J1201. |
| 11 | +- Redesigned the analog 3.3VA voltage supply with a capacity multiplier and a separate LDO after the 5V Buck converter. |
| 12 | +- Introduced a seperated analog section on the board and placed the regulator, filter and sensors there. |
| 13 | +- Replaced the bluetooth module with an esp32 for improved bluetooth and wifi connectivity. |
| 14 | +- Removed the low cost Gyro, Acc and Mag components and addded 3 mounting holes in 0.8inch distance for sparkfun headers. |
| 15 | +- Removed the second MS5611 and improved the layout. |
| 16 | +- Replaced the existing USART-3 connector with a Pixhawk standard JST-GH 6 pin Connector to connect and supply DGNSS simpleRTK2B+heading modules. 1: 5V_IN, 2: RX (3.3V level), 3: TX (3.3V level), 4,5: Not connected, 6: GND. |
| 17 | +- Changed to two single RJ45 connectors for CAN and RS232. |
| 18 | +- Added a footprint for a milled pressure hood including mounting screws to connect static and pitot on the pcbs edge. |
| 19 | +- Redesigned the digital voltage supply regulators and added sufficient capacity. |
| 20 | +- Added a separate boost converter to boost the USB Voltage. |
| 21 | +- Added a Larus Symbol on the board. |
| 22 | +- Changed the SMA to a u.fl connector for the GNSS Antenna. |
| 23 | +- Added active current limiting of GNSS antenna feed with circuit taken from the U-Blox F9P hardware integration manual. |
| 24 | +- Added ESD-protection diodes for voltage supply, GNSS antenna and USB connectors. |
| 25 | +- Added thermal reliefs on copper fills to improve hand solderability. |
| 26 | +- Added more status and error LEDs and labeling. |
| 27 | +- Connected USB, RJ45 shields and aluminium enclosure to a separate shield ground net. Routed the shield ground around the PCB and connected it on one point with a ferrit to ground. |
| 28 | +- Changed the RJ45 CAN pinout so that a twisted pair of a standard patchcable is used. |
| 29 | +- Improved anti-alias filtering for supply voltage measurement. |
| 30 | +- Added a switch for boot0 at the pcb edge. |
| 31 | +- Added the missing GNSS reset pullup resistor. |
| 32 | +- Enabled detecting the hardware version with an adc input and a 1:1 voltage divider for this version. |
| 33 | +- Decreased testpoint size to 1mm |
| 34 | + |
| 35 | + |
| 36 | +# Ideas for next hardware iteration |
54 | 37 | - User switch at the pcb edge.
|
55 | 38 | - A single sepic converster e.g. LM3488 for 3... 24V input -> 5V output
|
56 | 39 | - Alternative Debug Connector TC2030-CTX-NL-STDC14 : https://www.tag-connect.com/solutions-target-devices/arm#s0
|
57 |
| -- Sd-card power supply switchable |
| 40 | +- Sd-card power supply switchable. |
58 | 41 | - 27R series resistors for sdio bus lines.
|
59 | 42 | - Connect GNSS-PPS to GPIO timer input.
|
60 |
| -- Fuses between RJ45 12V connections. |
61 |
| -- Change CAN1 to CAN2 so that the build in STM CAN-Bootloader can be used for flashing. |
62 | 43 | - Sockets for 2 DGNSS modules: https://www.gnss.store/gnss-gps-modules/145-elt128.html, https://www.ardusimple.com/product/simplertk2blite/
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63 | 44 |
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64 | 45 |
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65 |
| -## Links to parts |
| 46 | +# Links to some parts |
66 | 47 | Gauge pressure: HSCMRRV001PG2A3
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67 | 48 | https://de.farnell.com/honeywell/hscmrrv001pg2a3/drucksensor-1psi-i2c-digital/dp/3439040
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68 | 49 | https://de.rs-online.com/web/p/drucksensor-ics/2269696
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