3/11/2026 - Day 0-What led me to this?

So from a long time honestly I needed an easy to use interrupter that will work reliably, i tried building kaizer's musical drsstc interrupter but like stuff kept not working as intended and kept blowing up lmao,maybe thats due to skill issue for me at that time in 2023 but still even an 555 timer based interrupter never worked reliably.
So I looked in the market for current options for interrupters and I could not find like a readymade product or a proper project or prototype of a good interrupter thats using a microcontroller like esp32 that just works lol. I only stumbled upon the arduino chip based oneTesla's SD Interrupter, wanted one so bad but since oneTesla like doesnt exist anymore, I was at a dead end.
So I just moved on from this and just make a dumb interrupter from an esp32 and a tin can, and I never expected it to work at all! it worked beautifully and I got my first interrupted coil. Ever since that, I just wanted a proper project, something that isnt a tin can strapped to a tesla coil oscillator, a truly portable one thats nice to use, so I brainstormed for a while thinking of how can I build something based on the foundation oneTesla has already laid, and I figured out that building a true ESP32 interrupter with the latest stuff makes sense.

paint imagination lmao of product

Here is picture and videos of my tin can esp interruter that inspired me to make.WhatsApp Video 2026-04-01 at 10.29.51 AM

3/23/2026 - 3/2/26-Day 1- Wanted to make a concept before designing

I wanted to build a concept of this project and I figured out that grinding on the firmware is better at first since I wanted to build my firmware around the oneTesla SD interrupter one, and when I open the files, i expected it to be easy, just change few lines in the code change libraries, pins etc and the code will work on the esp32....
Nah. What,in the thing is this lol, so many files with so much confusion, and so much AVR only stuff like timers and stuff they dont work for the esp32 lmao :( u can see my directory of the og firmware the number of files it has.

u can see my original firmware directory :////

so after seeing that I just got to a dead end, so I just started hitting compile on esp32 board, and replaced blocks of code till the errors went eventually lol. Occasionally when i didnt understand at all few blocks esp in timer section (whats this TRCCA OCCA Stuuf :( ) I asked help of codex to fix few blocks,but thing is that broke the firmware even more :// pic of my codexx
So also for actually testing this i just entered random gpios for now.

3/30/2026 - Day 2- The Great Firmware refactor

Ok, why, why did the original code have so many files ahhhh and I am getting linking issues from all of them not properly there lol.
I mean, this wouldnt have been possible without codex listening to my rants about how it broke and proceeded to break the code again :///

plus 7th is my farewell too and i got board exams on 17th feb so i gotta finish something and keep lol

I think i am close though, mostly the timer parts are over and moved to esp32 timers timer1 and timer2 at that time later added 2 more timers
The timer is important part since it is only responsible for the majority of the stuff like th epulse output, music etc in my opinion thats why i amdoing it first, still have a lot left

3/31/2026 - Day 5 & 6 - The code compiles and I built a breadboard test

SOOO the code compiled,yes, I cant believe also, but with the help of google and codex arduino ide stopped shouting at me!! Before the compile after the timer part was over i just changed some constants in constants.h file for esp32 gpio pins for stuff and sd card wiring i did generic connection gpio from youtube tutorials,and the LCD part was easy i just needed to change the initialisation lines for my I2C display instead of parallel display and also the definitions for the lcd object and also changing the LiquidCrystal library for LiquidCrystal_I2C.
ignore error that is from no esp32 hooked up

Once code compiled i uploaded to an esp32 clone i had and i put together a simple breadboard test, and the sd card wont read at all.

So apparently the sd card module is designed in such a way that i cant plug it into breadboard and connect, so I just spent like 2 hours searching my house for female to male dupont jumpers, took a while but found them in many interesting places.

After i changed to dupont wires and hanging sd module the card got read successfully :)
and since i didnt have a optical fiber stuff like transmitter cable receiver to truly hook up to tesla coil to test and i alr killed an esp32 by the tin can method, so i just hooked up a speaker and some dirty earbuds to the gpio and heard the output lmao and jammed to the music.
And yes I recorded this video on the morning of the farewell on 7th lol, I was just happy my shitty code works VID20260207061241

4/1/2026 11 AM - Day (many days) - The greatest break of all time lmao

So I had no other option, but to leave this project alone till march 7th when my boards ended, i got cooked in the middle lol,but everyday I would just turn on the device and jam to the music.
Also when I had time ater studying I would secretly use the computer and I fixed one critical thing fault I saw, no good way of exiting menus.
Once you are in one mode u cant back out and i had to press reset on esp32 each time, so for fixed mode i made it so that long pressign select makes it exit, but problem is it made it jump between the both selection rows but ehh,I had limited time and it worked lol.
U can see this blockaint perfect bcs the if loop kept exiting till i held for long time and kept spamming select the rows lol.
Also for SD mode, i made a crude way of backing out, i made a folder on the sd card that is blank and when i hold select in that folder it will exit from sd mode. if i try to hold select in music filenames in sd mode it would spam play music, again it worked,but not perfect lol.

4/1/2026 12 PM - Day 7 of building - The restart

SO, exams are over, now have time, and I also saved up over a year to purchase a cheap toslink transmitter and receiver and a cheap plastic fiber optic cable and i wanted to try interrupting my coil.
Obviously the cheap toslink transmitter and receiver are NOT meant for my use and it didnt work properly only worked at high duty cycles since it is made for AC and it like preprocesses the signal to remove noise since its meant for digital signal, so a dumb dc pulse like mine gets thrown off. I should have saved up more like 25 usd to buy proper IF series or those broadcom ones but I couldnt buy lol, so i just cranked up the duty till it received and that also stressed my gate drivers on coil side and failed but thats offtopic.

I began the adventure again lol when the toslink stuff arrived all the way from digikey to my fulfilment centre(TYSM Aqtronics for handling all shipping&customs!!) in my country then to my doorstep!, let me attach pictures of me testing it with the toslink stuff and also video of it.

VID20260301171100
VID20260318142031 (1)
VID20260207061241
I spent all my money on pcb for main driver project and that doesnt work fully lol but I mean we cant do anything

4/1/2026 1:03 PM - A break ,yet again

I dont prefer not working on this and finishing this off late but I have no option lol I have limited time plus I am undergoing med procedures rn and getting checkups so many days are getting wasted and I keep getting higher pressure to finish off before the last lol. But I am trying to do some progress but I also do not have all my tools since I keep moving often. But I started a schematic as a concept but I dont like it now and kept deleting it since it is based on the ESP32 and i needed to use usb to uart chip and I cant solder that too (no hot air) since it is QFN often(CP2102 & CH9102) also no usb midi functionality lol.

I am thinking of something big, this break is also letting me brainstorm, I am considering ESP32S3 Wroom chip,Yes it is overkill and i need to like make supporting stuff for the bare wroom chip rather than slapping a small tht devkit on but I figured out it will be a good product, and also can get USB MIDI and also I want to get the N8 version with 8MB flash storage for future expandibility incase the firmware gets too big but this is very unlikely but the price is not much different.
Next I think once am OK I will start schematic design for my project!

4/1/2026 1:23 PM - Day 8 of Build - New schematic, New start

Ok, Now I have gotten an idea for a schematic!! I am gonna use an ESP32S3 Wroom 1 N8 microcontroller on my PCB along with supporting components we find in devkits like strapping stuff, power regulation,etc and I want to use a 162 I2C LCD display. My code always ran best on 162 but since I only have a 20*4 LCD donated by a friend, I did all testing using it. I do not want to use parallel display connection and want to use the display with the I2C daughterboard to minimise number of GPIOs used!.
I also then read through first the esp32s3 devkit and i followed how they wired the usb c port and also the esd safety they have done. I also saw how they have strapped pins such as IO0 and EN. Also an online image helped me decide what pins to use for my stuff like I saw many GPIOs most having 60us glitch at start so I searched for safe GPIO and made it my optical output, I think GPIO 38 is what I used.

heres what i followed and these came in very handy.
For SD wiring I went with standard SD wiring that people used in the internet tutorials and followed it.
Still some things like other ui stuff etc are pending but lets see. I am usign EasyEDA standard rn but may need to migrate later.
For LCD it is just I2C wiring I wired to I2C pins.

here is schematic so far,dont judge lol its still all in shambles. For Power previously I have made one like rocket ignitor I used its power section bits here so time is saved but it is simple.
people also recommended esd protection for sd card and i have seen in mobiles its presence so I added since risk mitigation is good.
Also, many confused me on what I need to pullup, I even considered pulling up clock pin to power via 10K but accordign to google its a bad idea ig so removed. I used resistor array for pullup u can see to minimise number of components to solder and also to order.

soon it will be over i think and i can build a pcb

4/1/2026 1:48 PM - Schematic is almost over, need to do midi part and fiber

So the schematic is almost over. I also tried to reduce clutter and confusion while drawing reading & intepretation so I put circuits in small boxes and moved and spaced them so they are not a large rats nest cluster.
I first originally put just my standard buttons and also i used capacitors for debouncing 100nF ones. Originally my ui used 3 buttons only, Left, right and select. I refer as now left and right but originally while writing code i did it as up and down bt left and right is correct sense. But issue i have historically is exiting, I need a good exit button but i cant just ad another button 4 buttons seems too much, and also I found adjusting via buttons stuff just didnt give that "feel" of satisfaction.
So like what any other sane person would do, I slapped on a rotary encoder with a switch. Finding the right one was very hard it involved translating chinese datasheets from lcsc and lcsc scrolling lol but i picked one finally and its ok priced too. I hooked up the encoder phases and its switch and I think I will use it as the new SELECT button the internal button and the old select middle button will become back button.

I used GPIO 4,5,6 for buttons for no reason, same for encoder GPIO i used free pins in bit of a good order lol.
Still the fiber output is pending and the MIDI part which i think is hardest bcs all stuff I see is for 5V not 3.3V logic.
Also since DRC kept complaining ahh I put no connect for all not used pins.

I also added some indicator LEDs for power indication and i plan on adding for fiber out too

4/1/2026 3:02 PM - Day 9-Schematic is done, time to design pcb

So finally I have finished the schematic. The fiber optic part was easy I only had issue finding the right parts and some calculations for the right currents for safe optical transmitter operation and I finished in like 30-45 minutes mostly calculation and research but in the end I picked this specific transmitter HFBR 1521Z,yes it is on the pricy end but it is the actual part I need and I dont want to just do sketch stuff like with toslink just because its cheap,I want to do proper stuff lol and I dont to do sketch.

Also I needed to add another power bus voltage, now have added +5V with help of another LDO AMS1117 5.0.
I have also added a electrolytic THT capacitor across power for the fiber optic to ensure clean proper power supply to it and not any dips in power.

Above is the new power section.

Now, the MIDI section may look simple, but holy smokes it took me a while and going through so much datasheets and MIDI specifications to make this since like if I mess up any resistor value and it gives wrong logic level my ESP32S3 will be damaged very much. This took close to 4-5 Hours :( so much time but I am glad it is over.

Here is the new full schematic,I have neatened it too :)

SchematicESP32-sd-int2026-04-01

4/1/2026 3:24 PM - Day 10 - PCB time starts!

OK, now that the schematic is fully ready. It is time to create a PCB design!
So now initially I wanted to use only 2 layers, I mean why unnecessarily 4 layer pcb? Its dead cost and I always design 2 layer ones only so what I decided is I will not use the inner layers and try to finish routing.
Now, I want to ideally make a PCB in a small size below 100mm height or width is my aim,since when I tried to order a PCB with dimensions lit 165*105mm they charged me a LOT with engineering fees and for a 2 layer pcb I paid a lot to get fabricated.
So I set the board outline to initially I could not fit anything on the PCB and i kept like 100mm width by 105-110mm height when I started bringing everything into the outline.

I placed the easy parts first, then something came in my mind, I was being an idiot this entire time forgot I can place stuff on the backside of the PCB lol. Then I moved many things from resistors,caps,resistor arrays mainly etc to the backside lol. Now i shrunk it to 95mm width and 65mm height.

Unrouted PCB.

First thing I did was create a LOT of copper pours everywhere so I dont need to route power and gnd everywhere for example and also for cooling for regulators and mainly for EMI protection.

You can see I am copper plane maxxing lol. I also did some of the silkscreen text since it is very much easier to assemble knowing what stuff are lol, from experience

4/1/2026 4:01 PM - PCB routing....

Ok, I give up. I just could not do it properly in 2 layer board and I used Inner 1 for routing stuff that just isnt right routing again and again via after via or where both top and bottom layer traces run I cant run right, so used inner 1 there. Inner2 layer I kept as a solid, uninterrupted plane with no breakage and is continuous since I want to use it as a ground plane since the bottom layer is also ground but it is interrupted by button layer traces.
I also did research for USB routing and apparently I needed to maintain 90Ohms of impedance and differential routing. I used JLC's impedance control calculator webiste and got the values of spacing about 0.2mm and the track width of about 0.136mm. The problem is I could not differential route the USB data traces in EasyEDA standard so I have created a copy of the project then I migrated that project to Pro version fo easyeda. I dont know how to use EasyEDA Pro so it took some learning curve lol so I took more time for this. Routing the SD traces was also very difficult. Let me share some experiences.

here is the pcb after everything in standard is over.

When I was routing, this seemed fine
But later I now find new ratlines even after routing, find 3.3V already linked and routed now again wants routing and shows ratline. I turn on show copper plane and see that the traces were cutting off the plane's power connectivity lol ://

kind of like this but here one side connects so no problem but that time it was fully isolated.

here also in bottom layer I got the issue lol

Soon I will finish the rest of PCB in EasyEDA Pro and we will see!

4/1/2026 4:36 PM - Day 11 - PCB Work is over for now

So I have migrated to Pro version and finished the routing work for the usb. One thing is it took me such a long time routing this differential track bcs of my learning curve esp it was my skill issue lol then later I got perfect result.

Also I forgot to mention so far, I made sure to not disturb the ESP32 antenna and in old standard version I have to create this no solid region in every layer so no copper is under the ESP32S3 pcb antenna. But here now its easy I place a prohibited region and automatically it prevents stuff under the antenna. Tbh it is better to leave the pcb antenna floating from the board like Espressif did for their dev board but I ideally dont want a weak point, hanging thin pcb there that can easily snap also its pain to design with it in mind so I made it like this but no copper under the esp32 pcb antenna region.
Also more importantly I have moved the optical fiber transmitter if you notice you can see the change since once I saw a proper datasheet of it, it recommended me to keep this connector part outside of the pcb and where should be the pcb edge and stuff and followed it. I have alsso moved some ports slightly but that is not much big of a difference. Still I dont have clarity on 9V battery since I designed it with a barrel jack so I can plug in but dont want a 9V dangling but lets see thats my future problem ig I will ignore for now.

You can see no copper.
Now I think the PCB work is over and I can move on to making the case for it.
Here is some pics of the PCB now.

I also added some more silkscreen and my logo to the pcb!

See you in the next! I am planning on using OnShape but I have to learn CAD software because I have not used any form of mechanical CAD software like it only EDA and Electronics.

4/1/2026 5:11 PM - Day 12 - A new start - Case for it

So this is where it gets really time consuming since I literally have no idea on how to 3D model, but like any other other person I followed this meme
and continued.

I first did an import of my PCB into OnShape and like all the parts were haywire like pcb was seperate and all the parts on the pcb were imported into one bunch lmao and like it required me to place each part with a transform on the pcb like tf, no sane person would do that but again this is due to my skill issue lol, I immediately googled it and got my answer of composite part, import to seperate parts studio and stuff, then I try to move the pcb it aint going anywhere,learnt something called translate like that needed to move then I was able to do.

I would not go much in detail about every single step like every single mouse movement I have done hereafter since I have to then log so much so for easy process I would like to simplify but still include pictures and stuff.

I started off with PCB and parts in the top plane of my document and I have drawn a sketch for a case bottom piece.

I will continue in next journal since this is getting too long

4/1/2026 5:42 PM - Day 12 - Case - Bottom piece start and battery

So I started on the bottom piece now. As mentioned I have drawn a sketch with the pcb in reference, I have left plenty of room since I dont want constrained and also when I do shell operation I will lose some space because pcb will be inside shell.
I extruded the sketch.

Also note: I made up my mind and realised that 9V battery externally dangling is not ideal, and also routing the wire from outside to the barrel jack to an internal battery case is pointless. So I came up with an idea on paper and quickly drew one plan on how I would power, I changed the pcb slightly that I first added a power switch which was long missing in the middle and also removed barrel jack for internal pin header where 9v battery wires will plug into.
New PCB
New Latest Schematic project schematic(updated):

After extrusion I used shell operation to make this shell.

Now we got the base line of how this should turn out

Now I drew few sketches on all the ports and stuff that need the shell material removed so they can pass out and dont intersect the wall. I also drew sketches for the battery compartment I had on mind and also the wire routing. Let me attach pictures they are self explanatory.





Then i used remove in extrude and removed and created necessary holes and cavities for the ports and for battery cable.


Then sketched up pcb mounting holes and extruded.

fourth hole position not there since pcb doesnt support it it uses its 4th hole for LCD mounting.
Will continue with battery compartment next.

4/1/2026 6 PM - Day 13- Case-Battery holder

I now have made the battery holder. It encloses the PP3 9V battery. I took diemnsions for it from the help of a 9V I had in a multimeter. I took references and stuff needed for storing 9V from the multimeter and applied.
Yes this is gonna be now not much ergonomic but battery holder is absolutely needed and I made everything with minimum size required for good design.
I drew sketch for the holder dimensions and stuff.

I extruded everything and also created the necessary cavity by remove extrusion feature. You can also see the cable duct here connects to the battery cavity
I also put fillets.

A giant round rectangle extrusion sticking out looks awful, so I used draft.

I also put fillets on edges of bottom case so it feels better to hold.

Note I am not doing super weird geometry or angles and stuff to ensure it is easily 3D printable and not wasting unncessary material.

I then made the lip like removal of material so the lid for the battery compartment sits flush. I also put holes.

Note that hereafter when I make holes fo rmounting stuff I made it for M2 brass inserts from OnlyScrews, I got dimensions of it from their website and I design around it.

Then I made the lid for the battery compartment. You can see it can lie flush with rest.


Lid has holes for M2 bolts.

And the battery compartment is ready!
Here's another thing I did at the side other tha battery compartment, I made a wall like structure on the SD card port so the micro sd card cannot fall under the pcb while trying to insert into slot on pcb. Very often this issue comes to me when I try to put sd card into my Pi 4 SBC it gets stuck between pcb and case cavity under and have to disassemble to retrieve so I did this.


You will have the question then why the big slot like in the under edge, its for ease of access, you might be able to get the card out without it but my big fingers and of others need it lol. Its significantly easier to have the card accessible like this I took inspiration from Pi 4 board cases.

4/1/2026 8 PM - Day 14 - Modelling of Top part case 1

Today I modelled the Top case of the project.
I had copied the original sketch 1 for the bottom part of case over to the other free space in the top plane you can see it.

I have extruded it

Note that for rn I will have the imported PCB 3d model suppressed bcs my laptop is blowing up if I work with it so will unsuppress when needed.

here is it shelled and filleted


Then I drew 2 sketches to first add a solid extrusion projection below then another sketch to remove extrusion creating hollow cavity in that solid making a surface lower level than the level of the top lid for the buttons.

I then transformed it to over the pcb and I also enabled the imported pcb 3d model, yea my laptop is super laggy after this. 279 parts is no joke. better than 600+ for silkscreened pcb model.

here is with pcb unhided

And yes you can see the parts rn are just sticking out on the soild top lid not having hole to get through and they just intersect.

4/1/2026 9 PM - Day 14 - Modelling - Top case lid - 2

After transforming the top case onto the appropiate place and also unhiding the PCB & components now I cut out holes and slots etc for all components that get through the case like the LCD, buttons,Rotary encoder.
I have sketched and then extruded remove operation.

all cutout

Then I did a chamfer between the cavity of the buttons and the top surface of lid for better use and it will be good design and have better ergonomics.

I tried a fillet too, I liked it but it will be harder to 3D print so I did not want to put extra burden so went with chamfer. For same reason I have not used any special cool graphics since I want practical functionality and easy printability and less filament wasted so money is not unnecessarily wasted.
I might add my logo on there since it is simple text logo lol.

I then put on text for controls.

I am also considering removing this text I originally put since it looks chopped(very bad).

and replacing with this lol

looks good now

Now I drew more sketches and put holes on the top lid for mounting lid to base.

The hole I put is counterbore so bolt stays flus. I also used this opportunity to use measure tool to measure stuff and distance and by the distances I accordinly put bolts in my OnlyScrews cart I put M2 6mm for this.

And the lid itself is done!
Next only the mounting of lid to base part some modelling in base and final touches and a knob for the rotary and this part is over!

Here's a bonus video of me working on the go too lol.
WhatsApp Video 2026-04-02 at 11.12.07 AM

4/2/2026 1 PM - Day 15 - Final modelling part and final touches!!

I should have done this part making necessary hoes and extrusion and stuff in the bottom case before i made the holes in top case itslf but its fine.

I could not directly put holes in the shell part was too thin so madE this extrusion using arc sketch.


put holes also again for M2 brass insert from OnlyScrews(they just made their buisness name itself a meme atp lol)

You might have also noticed a wild new knob! Yea I modelledthat in a seperate parts studio seeing a tutorial and I gave character into it lol.

Heres da knob.

I think da knob will be a bit challenging to print though with FDM, thats why I made another knob simple cylinder to the side.

Well, I also put some more chamfers for the usb c port cavity.
And yea I never mentioned why that cavity and stuff, many imes many cables DO NOT fit into lie my phone witha case for example, to solve that issue I mad this cavity so wire can fully go in. I decied dimensions based on the fattest usb c cable I found lol.
Every single design in my case is for a valif reason, except my logo ig but it gives charater!!

One thing I kind of forgot int he top case modelling part is the cutout on the top case too for the MIDI jack.

I wish I can get rid of this old jack in the future, it gave me many hurdles in designing lol.

And here is the final build uninterrupted with sketches!! Am glad I am done with it.

without lid

Here is a 9V battery we have here this exact one and you can see it fits nicely with much extra room!

Overall, I like how my case and the project turned out it looks very good :) my dad who's a mech enginner saw it and liked it

4/2/2026 3 PM - Day 15 - Modelling - Exploded views and the final project

I like it so much how it has turned out, here is a bunch of pictures of my model.

All models and stuff and parts etc for my project are in my OnShape document
OnShape document

Btw again posting this is the new schematic I changed a bit like the power switch and the 9v battrery part in EasyEDA pro mid design of the bottom case

ALso here is assembly tab file. This aint required since I have alr provided link to onshape but still let m ekee files I exported.
ESP32IntAssembly

4/8/2026 - Some Model changes

Soooo I have been waiting for design review yet, but in the meantime I did not waste time and I took a look at the model and I also considered DFAM (Design for additive manufacturing) and I have tweaked some designs in my case so its printable easily and uses less material and supports. Also overall my brother recommended to not leave sharp edges and add more fillets.

I also took this opportunity to align my unaligned logo lol.
Here is the final top case with fillets.

I also made changes to the bottom main part of case you can see fillet for battery area projection has been added.

And yea, if you noticed the change of knob, you have good eyesight!! As I told I considered DFAM and that fancy knob looks good, but it is not printable and the ridges wont come,and it would have a bad surface finish. So I made a new knob from scratch!!.

I think it looks good.

I also made cutouts for the LED indicators to shine through! I originally intended it to be debug internal leds but ehh let it shine!.

4/11/2026 - MOREEEE CHANGESSS HEHE

SO I CHANGED SO MUCH lolll. For DFAM and FDM printing ofc.
I sliced in Bambu Studio and got ether so much support or little support but on the UI cavity, ugly and bad surface and hard to remove. I feared that I have to spend hours removing it and it will be ugly, def ugly lol.
So my brother recommended me to seperate parts and make stuff snap fit, the UI panel and esp the battery holder section.
He recommended cantilever snap fit type but I didnt use that for the UI panel I went with a simpler option for UI.

I first went with the seemingly easier part of this,the UI plate.
I first just before annhilating my previous work I just sketched over the existing lid then made this new UI plate and made this system attachment system.
Btw everywhere here FDM printing tolerance is considered I have done 0.5mm.

new lid
Here I have done a positive extrusion on the UI lid.


And a similar negative section on the case lid.


And position and size of lid has been adjusted madeshorter in elgnth and having more breadth now and bit centered to LCD

Next is the battery holder part i think hardest.
Till then peace out, and I am also happy that got prelim approved finally!!
TYSM guys

4/13/2026 - MORE CHANGESSSSSSSSSSS

SOOOOOO I did not want to remove so much support material or have an ugly surface due to supports while 3D printing, I checked everything by slicing for Bambu Lab A1 and saw so much support that I would have to scrape away carefully, potentially breaking delicate structures in process.
Mah bro saw it and he told to make the stuff into seperate parts like the cavitu ui cover for buttons and knobs and the big battery bulge and make them snap fit. He showed me 2D drawings for cantilever ones and also showed the tolerance to follow 0.5mm for my FDM printing and I made the UI snap fit.
I am working on the battery bulge which seems to be the hardest.
One thing that frustrated me was that the ui pieces i cannot simply take out, I did everything as add part function adding pieces to main lid. So I had to painstakingly fix every error for every function after changing the add function for the ui to new part. ://

Before

After

Most of my work gone there lol, but what I did was skecthing on top of that work beore removng iso dont need to redo. I als changd the alignment ad dimensions of that UI section to have greater space and for better looks
Here is the new seperated UI piece

As you can see I used this s an opportunity fo clearer not cut off text for the VOL SELECT above and below of knob hole.

For the UI panel lid thing instead of cantilever hook I went with this snap fit design.
I kept positive on the ui piece since if it breaks it is small part to reprint and improve.


You can see this projection and here is the negative side on the top lid.

I made sure that the negative and positive have tolerances correct so they fit and also I put fillet on the negative in insertion assembly direction for easy installation.

4/20/2026 11:06 AM - Battery Holder snap in system.

SO since i could not delete the prev jpurnal as of now it is duplicated so mind that,butI finished the hardest part which is the battery part.

First you can see the level of construction that was needed lol. and I made these slots in the main case with tolerance for FDM in mind so made it bit bigger so part fit.

Then later I have drawn few skeches on the battery holder part and extruded some parts as you can see to make the cantilever.

Then I added some filletto at the root of the cantilever for structural support. I referred a website for the radius of the cantilever.

I have then put some chamfers to make up the cantilever hook design.

so I think the part on the battery holder piece is over next should adapt the case bottom to hold it correctly

4/20/2026 11:14 AM - Battery snap in system-2

So in the prev journal at the start you could have seen me making slot for the battery holder but that was rough now here is how I made the proper slot.

For making of the slot first I took help of the assembly and I fit together stuff to see how ti fit and I made micro level adfjustments for the cantilevers to fity and be ideal for assembly you can see in the above pic it is correct.

Then since I made fillets for the cantilever root, I made fillets bit larger radius on the base piece too.

And I think that is it from a logging point of view, since I cannot reverse and show every micro adjustment for that damn cantilever in onshape easily, even for this so far I suppressed and unsuppressed functions!
I had to do mm by mm adjustment so the cantilever design worked with tolerance for FDM.