My PCB Projects
This page features some of my smaller PCB projects, in order of how cool I think they are.
C.H.E.S.T.E.R (22/04/2022)
CHESTER is an acronym... but I forgot what it stands for.
All-in-one control and drive PCB for small-to-medium robots. In theory it is the only thing needed in between the battery, actuators and radio.
- Espressif ESP32U module used as MCU and 2.4Ghz Reciever. A corresponding ESP32 transciever or another CHESTER board allows 2-way communication over ESP-NOW.
- 4 X 5A H bridge ICs drive up to four DC motors, or two bipolar stepper motors
- LSM6DSR MEMS 6-Axis Gyro Accelerometer for velocity PID or dead-reckoning
- Built-in battery protection and low-voltage sleep function
Wearable Project - Evaluation Board (26/11/2023)
Part of an ongoing project to try and develop wearbles, such as a wristwatch, or even a smart ring.
- UBLOX ANNA-B112 is an extremely low-power and TINY SOM, based on Nordic's NRF52. It is capable of Bluetooth-Low-energy (BLE) for communication with nearby smartphones.
- It is a challenge to drive small vibration motors using even smaller batteries. I used a 3.7V-to-5V boost regulator slowly fill a CPH3225A 0.01F micro-supercapacitor with enough charge to run the vibration motor for ~5s at a time, at a greater current than the battery is able to provide.
- On board LiPo charge protection using BQ298
- In-PCB capacitive touch array based on Cypress CMBR3108 Interface IC
- ARGB LED array as low-res, extremely-high brightness display
SLA Battery Tester - "qCard" (02/02/2023)
Designed to be an extremely cost-effective and easy-to-manufacture battery tester for 12V sealed lead acid batteries, which are standard on FRC robots. My team struggled with organizing charged and uncharged batteries, and we have accidentally installed dead batteries more than once. The idea is every team member could have this item on their keychain so that anyone can identify charged batteries.
- SB50 Andersons connectors are standard on FRC batteries. The qCard uses the PCB to directly slide into the connector.
- Can be plugged into the connector either by using a mirrored footprint on the PCB's rear
- PCB is designed to not require an enclosure to be robust - Low profile SMDs only, outer edge has grippy contour, keychain hole on top.
- ATTINY-1616 MCU can be programmed and tested using alligator clips on the rear test pads- alternatively, a bed-of-nails can be configured to interface.
Sensed 3-Phase Brushless Motor Controller (04/11/2022)
Controls a 3-phase sensed BLDC motor at 12V and up to 40A Continuous. This was a stepping stone to a custom motor controller for FRC and Combat Robotics, which, as of 2024, is yet to be made.
- Based on Infineon IRF7840 power MOSFETS with LM5109 gate drivers
- Sense resistor for overcurrent protection or current-regulated chopping
- Original design had an STM32F0 MCU on the PCB. To reduce bring-up costs and difficulty, this was removed, in favor of an external, validated MCU.
