Felini - Revolutionary Pocket-Sized Electronic Lab

Extremely affordable pocket-friendly, designed to provide a wide range of hardware testing and debugging functions in a compact and low-cost

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Felini - is a compact device for experts and electronics enthusiasts alike. Just like a Swiss army knife, Felini is designed to efficiently replace multiple common tools in the electronics field.

The story behind this project

In the past decade, we have utilized our superpowers to address various issues all around the world, whether it be creating tools to assist people with disabilities, traversing the depths of the ocean with exploration robots, spanning across rivers and swamps with environmental sensor networks, or harvesting energy from every corner of the Earth, sometimes connecting with satellites in distant skies. But now is the time for us to turn around and craft tools for ourselves. And good tools are the foundation for creating great projects.

During my student days, my backpack always contained a bunch of tools: a multimeter, a programmer, a USB to UART converter, a power adapter, and a variety of modules, accompanied by a prototype board for continuous programming and research, whether I was in a dormitory, on the campus, or somewhere in a lab. I often envied my IT friends who had nothing but a sleek and simple laptop. Even after graduation, the situation didn't change much; I still carried a small toolbox with items like a logic analyzer, a JLink programmer, adapters, etc. I believe that many people all over the world face similar challenges as I did, and it's time for me to solve this problem.

HACKADAY project goals

After several months of iterations, the project's vision has materialized into what you see in the project's images. My goal is to create a compact device that can fit into a pocket and operate independently without the need for a laptop. In real-world scenarios, such as working with robot circuits, car systems, or indoor sensor networks, it's not always feasible to carry a laptop around. The device's small size and standalone functionality will make it convenient and everyone's favorite pocket companion. For instance, I can read and explore the canbus network of a hotel even while traveling!

When returning to the laptop, it should seamlessly integrate with the laptop to fully leverage its inherent capabilities. In the past, we've had "multi-functional" devices like Bus Pirate, JTAGulator, FT2232, etc. However, these devices always required accompanying schematics and pinout diagrams, which proved to be quite inconvenient. I don't want to spend additional time browsing the web and searching for this information before plugging the dupont cables into the device. That's why with Felini, the pin map for connecting the wires will appear directly on the screen, making the process much smoother and hassle-free.

Compared to the initial ideas, Felini has been simplified to be more budget-friendly. The Felini project aims not only at engineers but also at being a user-friendly tool for students. Some common features like DAPLink, Logic analyzer, signal generator, USB to UART/I2C, which do not require external hardware, in the future, when the USB control command stack is completed, can be fully deployed on any affordable esp32 kit available on the market. For the full version of Felini, everything is open-source, from PCB fabrication, SMT component assembly, to enclosure fabrication, all can be done at JLCPCB. Therefore, anyone passionate about electronics can create their own version.

Specs & features

So what can Felini do? Felini was created after three trial versions, striking a balance between cost and complexity, while possessing the following technical specifications and features.


Operating voltage3.3 - 21V
USBUSB2.0, PD2.0, 3.0, PPS
Power output 3.3 - 21V (using PPS)
ButtonPower button, Encoder button
Operating SystemFreeRTOS
DisplayLCD TFT 240*280 Touch
CPUESP32S3 240Mz
Memory8MB PSRAM, 32MB Flash
ConnectivityBLE/ WIFI 2.4ghz
CAN 2.0
JTAG, PWM, 1Wire
USB 2.0


  • Intuitive touch display screen
  • Flexible pinout interface
  • Power Delivery capability and USB communication via Type C port
  • Touchscreen with value fine-tuning through an encoder
  • Wide power source compatibility ranging from 3-21V, with automatic seamless switching between...
Read more »

step - 22.69 MB - 08/05/2023 at 15:38



Demo firmware for Felini (beta version)

octet-stream - 1.46 MB - 08/01/2023 at 09:08


Adobe Portable Document Format - 872.88 kB - 08/01/2023 at 09:03


  • Integrated logic analyzer - Sigrok Pulseview

    Chu Tien Thinh (obitvn)5 days ago 0 comments

      Hello, I'm back.

      A Logic Analyzer is an indispensable tool for debugging electronic circuits, and Felini will have this feature. Most of the logic analyzers currently not made by Saleae use fx2lafw, running on the FX2 chip series with the GPIF peripheral. This peripheral allows direct data transmission from GPIO to USB, without involving the CPU. As a result, the FX2 with an 8051 core still delivers remarkable results. Due to the USB bandwidth limitations, logic analyzers running the fx2lafw firmware are capped at 24MHz. Unlike the FX2, the ESP32 lacks GPIF; however, in theory, the ESP32S3 can capture at up to 80MHz (maximum), which is the goal I am striving to achieve. Felini LA will work with the open-source software Sigrok PulseView, using the SUMP protocol to transmit data over USB CDC in the background. To be honest, I wish to implement a different protocol on the ESP32S3, allowing it to maximize the hardware USB speed and have liveview capture capabilities. However, time constraints do not permit me to do so.

      Additionally, the number of samples and channels also need to be considered. Based on my own experience, I will prioritize the number of samples over the sampling frequency. Below is an update on progress and achievements: Pulse has recognized Felini and is operating at a relatively low speed.

  • ESC/Servo Test

    Chu Tien Thinh (obitvn)08/21/2023 at 08:03 0 comments

    The tool that Felini will replace in this log update is an RC ESC/Servo tester. Servos require a pulse frequency of 50Hz, with active-high time ranging from 0.5ms to 2.5ms.

    If you don't want or don't have a blue-colored Servo tester like the one in the picture, you will need to invest some time in coding and generating PWM pulses... just to set the rotation angle or check if the servo is actually functioning. This is unnecessary when you have Felini.

  • Similar to a voltmeter but more visual

    Chu Tien Thinh (obitvn)08/19/2023 at 15:50 0 comments

    I am still dedicating time to focus on the development of Felini, and the source code will be open in a few weeks, once everything is running smoothly. Felini utilizes INA226 to monitor the output voltage after communicating with the Type C PD power supply. When not using the power delivery feature, INA226 is utilized to transform Felini into a wide-range voltmeter with voltage coverage from 0-24V, sufficient to meet most needs in a DC lab environment. A notable difference from a regular voltmeter, Felini is equipped with a display, so we will have a small graph that makes it easy to observe voltage fluctuations that need to be measured.

  • Testing CMSIS - DAPLink

    Chu Tien Thinh (obitvn)08/07/2023 at 09:14 0 comments

    When I started concept prototype of Felini, I wanted to quickly determine if the Felini project idea was actually viable, and one of the parts I thought was the hardest part was implementing a DAPLink suite on esp32s3 , which no one has ever done before.

    And I got lucky, DAPLink runs stable on esp32s3 with cherryusb stack. At the time I started testing DAPLink porting on esp32s3 (March-2023), cherryusb stack only supported esp32s2, and I had to overcome another challenge, which was implementing cherryusb on esp32s3.
    As you can see, DAPLink works on Felini, with an intuitive pin connection interface on the screen, no need for diagrams, extremely simple to use.

    DAPLink shows up on windows as CheryCMSIS-DAP and comes with a usb to serial portDAPLink shows up on windows as CheryCMSIS-DAP and comes with a usb to serial port.

    And as expected it works with openocd.

  • 2nd prototype

    Chu Tien Thinh (obitvn)08/04/2023 at 16:50 0 comments

    The next version took some time to complete. From the initial concept, this is the third hardware version I designed. It has added an extra battery to enable standalone operation without the need to plug in a USB cable.

    To power on or off the device, I utilized the AXP173 power management IC. This IC allows you to press and hold the power button to turn the device on or off. It manages power, charges the battery, and automatically switches between USB and battery power in a compact size (5x5mm), replacing multiple ICs for these tasks and saving PCB space.

  • First Prototype

    Chu Tien Thinh (obitvn)08/02/2023 at 16:02 0 comments

    The first version of FELINI was a device consisting of 2 larger and rougher circuit boards compared to the current version, and it was not designed with an integrated battery. This means that it could not function without being connected to a laptop, external power source, or powered through the connectors located on the bottom side.

    This version was overloaded with numerous complex features and nearly non-functional due to missing components, as some of the parts couldn't be ordered. As a result, it only made it to the stage of 3D-printed casing assembly testing.

    The next version was attempted with modified component footprints, but it still didn't work, mostly due to my mistakes and errors during the design process. Therefore, I decided to start a completely new version of FELINI, which is the current version we have now.

View all 6 project logs

Enjoy this project?



zyndram wrote 09/10/2023 at 14:25 point

How plug in Irda?

How plug in soundmodem (look at android program rattlegram or waver) and send data trought walkie talkie.

How plug diode/flashlight and send data aplabeth morsa and meybe camera to receive it.

How create a mesh network using BT or CC1101 (433MHz or 868MHz)

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Index303 wrote 09/09/2023 at 12:24 point

Very good idea and design!  I can't wait to make one "felini", will the source code be open source?

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Chu Tien Thinh (obitvn) wrote 5 days ago point


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Kevincoooool wrote 09/04/2023 at 08:34 point

Hi ,Hello, how is the firmware development progress now

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Chu Tien Thinh (obitvn) wrote 5 days ago point video channel is yours, right? You have very impressive projects

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Paul McClay wrote 08/21/2023 at 00:55 point

Random idea: to make it useful in a breadboard, can you arrange pin assignments for the 2*11 header so that it's at least harmless to short across the 11 pin pairs? And distribute 11 useful pin functions along the header? Basic stuff like power (in or out), ADC, and whatever else fits. So that if stuffed into a breadboard it would a) not break, and b) do whatever functions you get to fit in 11 pins.

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Chu Tien Thinh (obitvn) wrote 08/21/2023 at 01:53 point

Thank you, I've been considering this since the idea, for use with breadboards it's better to have an adapter to get the most out of the feature. Felini can also be plugged directly into the breadboard because the pins in its two rows are not used at the same time.

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david wrote 08/14/2023 at 20:07 point

I'd be worried about bending the pins on the male header. How about changing it to a female header? You could use a male-to-male header if you needed the male pins.

  Are you sure? yes | no

Chu Tien Thinh (obitvn) wrote 08/15/2023 at 01:39 point

yes, it's personal preference, replacing to the female header is simple

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Prashanth Kumar wrote 08/09/2023 at 06:39 point

It would be good if you can make the software open source, so more people can contribute to it

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Chu Tien Thinh (obitvn) wrote 08/10/2023 at 03:16 point

thanks, it will definitely be open source, but I need some time to clean up code and prepare before people can contribute to it

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Prashanth Kumar wrote 08/09/2023 at 06:36 point

If you are willing to sell pre-assembled boards, please let me know

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Xieshi Zhang wrote 08/06/2023 at 01:02 point

Wow! Such an elegant and innovative solution to a common problem. I definitely need this.

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cheyen.s21 wrote 08/05/2023 at 13:31 point

Hey, would this be able to run or test usb otg connected webcams? Hoping it can test and display a usb webcam

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Chu Tien Thinh (obitvn) wrote 08/05/2023 at 15:37 point

yes it is a good idea, i will look into it in the future when the software is stable, thanks you

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cheyen.s21 wrote 08/05/2023 at 20:50 point

You're welcome, i've actually been on a quest for this such item for a very long time TBH and came across your post a few days ago and saved it at work. Would be amazing to see if this will be the all in one capable gadget. They are very low resolution for now  ( incase data rate is an issue or limited ) ( 256*192 25fps and 256*192 50fps no native MJPEG output though (but i guess the raw data can be converted or viewed raw? 

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Paul McClay wrote 08/04/2023 at 01:29 point

This sounds like a great "Gearing Up" project! 

As a power supply, does it trigger USB-C PD for high voltage & current?

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Chu Tien Thinh (obitvn) wrote 08/04/2023 at 02:31 point

In theory, it will support USB-PD and PPS to customize the desired voltage level, which will be output through the XT30-M port on the left side of the device. Currently, I am dedicating time to finalize this feature and many others.

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Paul McClay wrote 08/04/2023 at 17:30 point

Yes PPS is more correctly what I was thinking of. Liking the idea.

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