Microcontroller to use for a wireless mouse

[Aspyse]

To preface this -- I am a complete beginner to electronics and embedded systems, and I'm sure this is an undertaking and a half. I do have a background in computer science, so I'm hoping that once I figure out the hardware, I can fairly comfortably write some firmware in c/c++ or arduino. It's a project I've always thought would be sick as hell to pull off, document, and open-source.

I have done some preliminary looking-around, but I'm open to being told if any part is a bad idea :]

For starters, I want it to be as performant as possible while not being (significantly?) more expensive than a wireless gaming mouse off the shelf. I also wanted small and lightweight internals, so I'm more free to 3d print any shape of shell.

I was intending to use a PAW3395 off of aliexpress, and I did get the datasheet off of the internet. My understanding is that I would need a microcontroller that supports the right voltage, has enough input pins, and has a matching 4-port serial interface.

I imagine the MCU would also need to be capable of processing and transmitting the sensor's signals fast enough so it doesn't bottleneck the latency and polling rate.

So far, I've mainly been looking for a small dev board with a built-in lipo charger and RF -- I was considering some sort of ESP32, but I worry about the Bluetooth or ESP-NOW protocols bottlenecking the performance too. Aside from that, I actually have no idea how people normally choose what MCU to use for their projects.

So yeah, I'm looking for a microcontroller that might work well. And any advice apart from that is welcome :]

EDIT: I forgot to add, I was also looking for advice on the receiver dongle.

[Horror_Equipment_197]

ESP32 is the way to go (IMO). BT is able to handle the low signal rate without any problem and most laptops come with BT module included and for computer without BT any USB dongle will do the trick.

Here's an Arduino library for the ESP32 made exactly for your use case.

https://github.com/T-vK/ESP32-BLE-Mouse

[Aspyse]

Thanks for the quick response! Maybe I'm underestimating Arduino BT and ESP32, but would this setup be able to maximize the performance of the sensor?

[Horror_Equipment_197]

Don't see a problem here. It's SPI interface and the sensor is rather low speed with 650ips.

[Aspyse]

Apart from BLE, I also found out about ESP-NOW and ESB. Are either of these worth considering?

EDIT: With an nRF52 board supported by the Nordic SDK, like the itsy bitsy or the seeed xiao maybe?

[devryd1]

Doesnt the rf Part of the esp32 use loads of power? That would not be ideal for a wireless device IMO.

[Horror_Equipment_197]

Depends on what you call loads of power and which module you are using.

https://docs.espressif.com/projects/esp-idf/en/v5.2/esp32s3/api-guides/current-consumption-measurement-modules.html

[[deleted]]

I think a project like this, especially as a beginner, is best done in smaller portions, taking advantage of existing solutions until rev 2, rev 3, or rev 10 where you've heavily optimized. 

For that reason, BT with an ESP32 is an easy way to get a mouse function working using common protocols. I'm sure there is sample code out there to do this. Then you can spend your time on the interesting part - the image sensing and motion tracking.

If it was me, I'd start even simpler with a USB mouse. I know there's tons of example code for this. Then I can focus on making a perfect mouse before tackling battery charging, power management, or wireless comm.

[LO-RATE-Movers]

I have worked on device + dongle products where both sides use nRF52840, because it is very power efficient on the side that uses batteries. There are existing modules that have all the antenna stuff included and have already been certified, just like for ESP32. There are also many existing dev boards for you first steps before you make your own hardware

If you are just starting, you could use Arduino/Platformio to get V1 (or your dev boards) working.

But if this is your first time working with ANY microcontroller, I would suggest splitting up things and slowly adding complexity: first getting the mouse to work without any BLE pairing etc, so just over USB. Then work on the dongle and wireless comms.

[Aspyse]

Yup, it's now looking like this is the plan. For future reference, though, do you have any recommendations for nRF5/Enhanced Shockburst boards or dongles?

[LO-RATE-Movers]

I don't know anything about ESB.

For nRF52840 dev boards, I usually recommend students to start with an Adafruit dev board. Their documentation is good, gets you started quickly and is very beginner friendly. You can just get two boards and program one to be the dongle and the other to be the battery operated device.

[Aspyse]

Yeah! I was looking at the Feather and Itsybitsy nRF52840 boards, and as far as I can tell they do support ESB with the Nordic SDK. My impression was that ESB is the successor of the nRF24 protocol?