Rukus: Pocket Robotics Control Computer

Spent an hour organizing the crystal cluster cuz it looked kinda ugly and too close to each other which made them kinda hard to solder……anyways here’s the new result

After the failure, just in case it’s bc of any design issue here’s a couple changes I made:

• Removed RUN by simply crossing it out
• Replaced 10uF cap for AP62401WU with ceramic cap
• Removed PSYNC as it occupies GPOI23 and I just wanna get it work so bascially removed some complexity
• Added a couple TP pads just to make sure i wont blow anything up again when testing lol

GUYSSS I finally got my boards and gave the very first shot!
I gotta be honest popularizing the board is the most boring process, and it took me almost 1 and a half hour……And after spending almost one more hour of repairing I FAILED TRAGICALLY
But anyway here’s the result (look at the picture below
***Note that the hours were recorded the day before but now I finally have time to devlog

Finished and ordered my custom radio module!

• Cleaned up DRC (pls ignore lots of clearance issues as it was simply bc of the custom antenna
• Sorted out BOM
• Added tons of vias
• Removed solder mask (acc i wanted to test out both with and without solder mask
• Submitted my order
• Rendered the custom board

Spent some time on routing the my radio PCB, checking DRC, and re-arranging the layout
*** Damnn I just realized that I shouldn’t switch 0402 components to 0603 cuz the radio might somehow be detuned……..

Finished prototyping using my RP2040 custom devboard!!!
This basically validates my design for the PCB as it uses the exact same parts except different PWM pins
*** Note that I haven’t added nrf24l01 in my design as radio is very unpredicatable

YAYYYYYY this time I prototyped on my RP2040 devboard and DRV8833 even tho I gotta use an Arduino Uno for power supply. I tried to power L298N from my custom board but it didn’t work cuz the current spikes are crazyyyyy. But anyways huge success, next up imma connect it to my radio nrf24l01 and see how it goes

Huge success!!! I finally made two custom RP2040 boards communicate with each other through nrf24l01, and next up imma wires them to my custom board

Just tested out the transmitter, while testing out my RP2040 custom devboard!!! (huge success)
Pins:

• CSN: GP12
• MOSI: GP7
• CE: GP11
• SCK: GP6
• MISO: GP4

Tested out circuits on Arduino UNO + L298N first!!! Imma try out RP2040 and TB6612 later

Spent some time soldering all the components for prototyping

• RP2040 board (I made it myself!!! :)
• nrf24l01
• TB6612

DAMNNNN I just picked all the parts manually……guys MANUALLY
IT TOOK ME SO MUCH TIME (look at the price :( SO EXPENSIVE
*** BTW I also discovered how I accidentally used 0603 for a 10uF cap, but we got solutions lol

YAyyyyyy this time the layout isn’t too bad lol
Just spent an hour figuring out the layout and trying to connect everything

Damn I kinda messed up the reference number and the parts………I didn’t know that I needed to use 0402 lol
Anyways we can finally get into PCB layout and routing!!!

OOOOOOOO finally got to the most exciting part cuz guys radio is very sensitive to any changes!!!
But anyways WE GOT THIS lol
Btw i also picked the cyrstal (YXC Crystal Oscillators X49SD16MSD2SC) from LCSC let’s hope it works

Finished the schematic for the custom nRF24L01 module!!! YAYYYYY

DAMNNNNN easyeda cannot export to kicad for some reason………So I gotta draw a new one myself. Anyways after spending some time here’s the beautiful result

Finally copied RF antenna from the datasheet!!! It was kinda a hassle lol

Spent an hour on designing the schematic for the radio!! Im going build radio module first

Here’s a couple things I changed before moving on to nrf24l01 radio

• Changed 0603 47uF capacitors to 1206 so that it can handle 25V spikes
• Rerouted everything around the two capacitors
• Double checked the schematic and cleaned up the layout

After struggling for 2 hours, finally replaced the two inductors with 4mm x 4mm one!!!
*** You’ll see how much I struggled in lapse lol

NOOOOOOOOO I just noticed that I picked the wrong inductors……….I accidentally picked the 0201 one and that doenst allow enough current (like nowhere close)
*** Look at the highlighted part

WOOOO I spent so much time on fixing and rerouting AP62401WU……

• Added a Schottky diode to prevent current from leaking back feeding to AP62401WU
• Changed the placements of AP62401WU output capacitors as they may generate tons of voltage ripples and malfunction other delicate ICs (look at the highlighted components)

Well well well for the past two hours I was designing my nrf24l01 antenna and trying to implement it into my design
I thought I couldve just imported other people’s designs but HELL NAH
Here are a couple options that I can refer to tho

• AN043
• AN2731
• AN91445
  But ofc i lean towards the first one and im probly gonna copy that too lol

Alr last devlog before ordering!!
Double checked everything including adding more vias and ran DRC twice
One last glance at my beautiful PCB :)

Updated README and added a release!! Btw I also added a little sketch fab model

Rendered my PCB!!! And also made this blueprint style image (see the second image)!!!

I spent some time on reading RP2040’s datasheet again and learned that there’s only two SPI and I2C engines, with 8 slices of PMW

• Read RP2040’s datasheet
• Fixed PMWA and PMWB routing
• Rerouted USB-C cuz I decided to swap it with the 01x04 pin header
  **Now you can see all the parts beside USB-C are rerouted and USB-C is also moved to the top-right corner

Here’s wat i did for the past two hours

• Added a 100uF polarized capacitor to prevent 12V spikes
• Rerouted the 12V connection part AGAIN OMGGG
• Edited RT6154AGQW footprint
• Cleaned up DRC errors

Finally finished routing!!!

• Rerouted “EVERYTHING” for the two voltage converters (you can see it in my lapse
• Reassigned PWMB to GPIO27 so that I could add some more vias
• Routed everything and cleaned up the silkscreen

OMG this is getting frustrated!!! I really should’ve used 4 layer board lol
Cuz now Im having two troubles

• Some GND pins are still unconnected
• There are two pins far apart……but they are blocked by traces from MCU DAMN

After two and a half hour of hard work, I almost finished the routing!!!!

• 0.18mm
• 0.20mm
• 0.30mm
• 0.50mm
• 1.00mm
  There’s really nothing to say about this process, it’s just fun lol

I roughly positioned all the main components and changed the number of output pins to allocate for GND and 3V3

• Motor driver at the front, far away from RP2040 chip
• 45mm x 45mm dimension
  *** I would still need to change the order of pin headers to reduce intersections as much as possible

Connected to footprints!!

COMPLETED THE SCHEMATIC!!!! FINALLYYYYY
I tried to make the PCB in a square shape lol
Btw this only includes RP2040 and TB6612FNG motor driver, I’ll add nrf24l01 later

Completed the schematic for AP62401 (12V to 5V) and TBTB6612FNG!!!
Damn and I just realized that TBTB6612FNG is actually the chip itself lol
Any way here’s a little diagram explaining how the power supply works:
12V –> AP62401 (12V to 5V) –> RT6154AGQW (5V to 3V3) –> MCU
–> TBTB6612FNG –> Motors

Spent some time on finding voltage regulator to convert 12V to 5V so that battery can also supply RP2040 (ofc not directly

• Learned and decided to use AP62401
• Created symbol and footprint for AP62401 by referring to the datasheet
  Link to the datasheet: https://www.diodes.com/datasheet/download/AP62400.pdf

I was figuring out how to wire the RT6150AGQW

• Pico schematic uses RT6150B-33GQW but apparently no one is selling it or it’s too expensive
• Ricktek only shows the minimal design so I have to figure the math
  R1 = R2*(Vout/Vfb - 1)
• Imported symbol and footprint for both RT6150AGQW and MBR120VLSFT1G
• Fixed the symbol to stay organized

I roughly completed my schematic while referring to pico schematic
Here are sth I noticed:

• Should use RT6154A instead of MCP1700x-330xxTT for larger current
• Add schottky diodes if external power supply is needed
• Connect GPIO24 and 23 to RT6154A to monitor whether the board is either using battery or USB to switch between PWM and power saving mode

For the past hour I was reading TB6612FNG schematic and trying to apply it to my own. But here were the problems:

• I wanted to supply my RP2040 through both USB (5V) and battery (12V)
• What pins should I keep and crossed out cuz I wanted it to be minimal