I've heard that modern quadcopters use a DSHOT protocol. Could you describe what it is?
What's its purpose?
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1$\begingroup$ Again, this is multiple questions in one. Try to make your question more specific. $\endgroup$– Jacob B ♦Commented Apr 24, 2020 at 7:18
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$\begingroup$ Do you want me to split it into multiple questions like: - What is a DSHOT protocol? - What's the purpose of DSHOT protocol? - What does DSHOT600 mean? ? $\endgroup$– ZiemCommented Apr 24, 2020 at 9:04
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3$\begingroup$ If you were to ask the questions "What is a DSHOT protocol?" and the question "How does DSHOT work?" they could have very in-depth, completely different answers. So yes, splitting into a couple of questions would be good. For example, you could ask "What is a DSHOT protocol, and what are the different types?" and you could then ask "How does DSHOT work?" $\endgroup$– Jacob B ♦Commented Apr 24, 2020 at 9:18
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$\begingroup$ I removed some of the questions to narrow the scope down. $\endgroup$– ZiemCommented Apr 24, 2020 at 13:35
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1 Answer
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DShot is a protocol that flight controllers use for communicating with ESCs. It stands for 'Digital Shot'. It is a new digital communication protocol developed by Flyduino in collaboration with Betaflight as an alternative to Oneshot and Multishot.
Oneshot and Multishot (and standard PWM) all use analogue signals. The length of an electrical pulse determines the value being sent from the flight controller to the ESC. This can lead to problems with accuracy if there are slight differences between the speeds of the clock signals in the ESC and the flight controller (which is why ESC calibration is required with analogue protocols). Also, these signals have a fixed length range of 1 to 2 milliseconds, which means they can't be sent more often than once every 4 ms or so, or 250 times a second.
Digital signals can also be more resilient in the presence of electrical noise.
The number associated with the protocol indicates how much data is sent per second. There are several speed options available:
- DShot150 – 150,000 bits/Sec
- DShot300 – 300,000 bits/Sec
- DShot600 – 600,000 bits/Sec
- DShot1200 – 1,200,000 bits/Sec
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$\begingroup$ Brushless Whoop has a great technical explanation of the protocol, including the "bidirectional" variant (as in bidirectional communications over the same wire in a half-duplex way). $\endgroup$ Commented Feb 19, 2022 at 1:27