18/03/2021 New Motor Controller Breakout Board
We recently received our new motor controller breakout PCBs made by JLCPCB. This board will be used to connect the quadrature motor encoders and the main microcontrollers to the motor controllers of our robots. This new version adds a ground pin to the UART connector and makes the breakout board even more compact.
Our First PCB assembled by JLCPCB
We just finished testing our latest PCB design. The boards were manufactured by our partner, JLCPCB, but for the first time they were also assembled by them. We used their SMT parts library to select components and we built our design around them. For the first time, we also got to design a 4-layer board.
What we made is a controller board for the VL530X time-of-flight sensors from STMicroelectronics. It features an STM32F405RG microcontroller and it enables us to connect up to 10 ToF sensors in a single I2C bus. The PCB interfaces with them and sends the distance data via a CAN bus to our main microcontroller to be used for obstacle avoidance. Separating the data acquisition and the processing in this way helps us reduce cable runs and helps us save processing time in our main microcontroller.
Getting the boards assembled was pretty straight forward. After uploading the gerber files as usual, we also generated BOM file using the reference codes of the JLCPCB component library and a footprint position file for the pick and place machines. That’s all that was needed to order PCBs and get them assembled. We were really impressed with how simple the process was.
Getting the PCBs assembled saved as a lot of time soldering and also enabled us to use smaller components and make the overall design a lot more compact. We gained a lot of experience designing a custom board with an integrated STM32 microcontroller and ordering it with assembly. We are really happy and proud with the results and we plan to make more designs like this in the future.
01/01/2021 : Gifts from STMicroelectronics
Polybot became a partner of STMicroelectronics in January 2021. We have the honor to represent this great multinational, world leader which develops, manufactures and markets electronic chips.
We thank the company for the support given to our association and the relationship established between Polytech Grenoble and STMicroelectonics. It is with consideration that we represent the company at our robotics competitions.
To inaugurate our collaboration, STMicroelectronics offered us: 6 Nucleo STM32F446RE cards, 6 Nucleo G431KB cards as well as a STLink Extern.
09/29/2020 : Our first pcb order from JLCPCB
Recently, we received our first pcb order from our partners JLCPCB. The board comes in the form of an Arduino Uno style shield that is connected on top of a NUCLEO64-STM32F446RE development board. The shield can be connected to up to 10 VL53L0X time of flight sensors from STMicroelectronics. These sensors serve us an input for the obstacle avoidance system of our robots.
In order to communicate with all of the sensors with a single bus I²C, we need to change their addresses. We achieve that by using the XSHUT pins on the sensor modules that let us power them one by one during startup, which permits us to change their address.
The goal of the shield was making sure that the connections were reliable and secure, which we achieved by using JST connectors for all of the connections. The board also served as a great platform for learning pcb design and SMD soldering.
We found the fit and finish of the boards to be great and the ordering process couldn’t be more straightforward.
We’re looking forward to designing even more boards and certainly a few more complex ones. A board with a D-SUB15 connector for interfacing with our MCP230A is already in the works and we have also planned to order a more complex 4-layer board using an STM32 F4 microcontroller. That board could eventually replace the NUCLEO board and the shield while adding a CAN interface that could be used to connect all of our microcontrollers together.