Since our Spectral Micro BLDC drivers are close to being released from beta, we needed to develop additional accessories and electronics to assist with the drivers in building robots and providing users with control. The planned method for using Spectral Micro drivers is daisy chaining via a CAN bus. What better product to complement this setup than a USB to CAN adapter? Allow us to introduce the CANvas adapter! This fully open-source adapter boasts numerous features that no other adapter on the market offers!
Files to build your own: Link
You can buy one here: Link
CANvas is a USB to CAN Bus adapter ideal for robotic applications. It is designed to be easily integrated with all Source Robotics products. It leverages open-source slcan firmware, and the design files are also open source. This adapter is special with features like split termination, common mode choke, and TVS diode protection. By using these features, it employs industry-standard hardware to increase reliability, protection, and reduce noise.
TVS protection Diodes
A bidirectional TVS diode can protect the CAN transceiver bus pins for short overvoltage events. TVS diodes offer the most effective protection against ESD, burst EFT, and surge transients because of short response times of a few picoseconds and power ratings up to several kilowatts.
Common mode choke
Common-mode chokes are used in automotive CAN networks to enhance electromagnetic compatibility (EMC) by filtering out high-frequency noise from the ECU through the CAN transceiver. They also improve the transceiver's immunity to electromagnetic disturbances on the bus.
Split termination resistor
The split termination uses two resistors equal to half the cable’s characteristic impedance (typically 60Ω each) with a capacitor between the common-mode point and ground. While it uses more components, it creates a low-pass filter for common-mode noise, improving electromagnetic emissions. The RC components form an RC low-pass filter with a specific corner frequency.
If you want to learn more about CAN here are some great reads:
https://www.digikey.com/en/articles/design-in-tvs-diode-protection-enhance-can-bus-reliability