@Sreeni

So Today I finalized my BOM and my cad, I tried out blender for a while and realized that I was just not made for it, I’ll try and learn it but it will take a while probably, for the pcb I was able to bring the cost down to around $250 which puts me within the budget and I also made a stencil on google slides which I will paint onto the rocket as like a livery to make it look nicer, Other than that I finished some small drc errors on the pcb and thats it I’m going to be submitting and hoping!

Devlog 10:
-Did most of the schematic wiring.
-Did a bit more research on the motor and the “motor driver”.
Extra:
First of all. Making the schematic isn’t fun AT ALL.
When I was making my Hackpad I enjoyed it a little bit.
But THIS.
…
It’s just painful.
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And the other thing is that I did some more research on the motor and it’s driver (not as in a chauffeur, but kinda like that). Since I don’t want it to disturb the other components with it’s electric fields.
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Anyway. There isn’t much else to report on, so I guess we are done for today.
And I’m tired.
Gn

So I built this project as a ground station for my rockets, I’m following a tutorial from blueprint and so I First did a schematic and took forever to assign footprints, and then I Grouped everything that needs to be together on the pcb but I haven’t routed yet which I will do soon.

So today I mainly worked on my pcb and Bom, I first started by making the BOM for the project and finding the cost of everything I would need, The main cost for this project are for the main flight computer which is around $400 which is crazy but I have someone who works at jlcpcb who sponsored an old project of mine and could help me with this, Other than that I need around $270 for the main rocket but I think I can bring that cost down. Also after asking for help in a reddit rocketry channel I was recomended to use an off the shelf flight computer because it wouldn’t be a good idea to put a brand new flight computer in charge of pyrotechnics. For that I chose the Eggtimer Quantum which is a cheap $40 flight computer which will control the pyro charges. I also worked on the pcb and solved some drc errors, and finished routing some small resistors and whatnot, I still havent heard anything about the missing lapse for the pcb but we will see, For now the final things will be to finalize the BOM wrap everything up.

So today I worked on integration, I first began by cutting out the holes for the servo motors to fit and then I installed the tvc mount into the main airframe, everything went pretty well although I overestimated how much of teh cardboard I needed to cut out and made a pretty oversized hole but it fine, My current servo push rods dont really work in the current airframe so I need to make new ones, other than that the resistors I ordered last time still haven’t shipped im going to call digikey customer support and figure out whats going on, I also have to finish assembling the rest of the components and then integrate everythign for its first test flight.

I’m actually about to end it all, I began pcb design and routing, and I did around 3 days of work totalling 19 hours, But I being lazy did all the work on one lapse, and I finished this pcb work pretty late into the night, so I decided to save the lapse and journal everything in the morning. Next morning I wake up and I go to lapse to sync my lapse with the project but then something happens. I open lapse and normally the old lapse shows up automatically, but it didnt. I then start panicking and try searching around, I look through my old lapses on the Lookout app and couldn’t find it, I kept looking and never found it even though I remeber saving it in lookout the night before. I’ve asked for a help in the stardance help channel and I’m hoping we can find it? if not i quit.

Other than I did work on my cad and layed out how everything will work. I’m going to use u bolts to hold all the parachute lines together, and for the avionics bay I’m going to use 3/8 threaded rods and 0.5in bulkhead made of wood. Other than that I just have to finalize the BOM for the project and then submit and hopefully fix the whole pcb issue.

So today I mainly worked on the CAD model, I modeled all the body tubes centering rings and started work on the avionics bay , I’m going to use around 1/4in wood as bulkheads and use 3/8th threaded rods that hold everything together + 2x 3/8 steel u bolt to attach the parachute lines too. The main avionics sled will be 3d printed and will hold the flight computer. Now After though I decided to make a new flight computer for this rocket because the previous one is more tailored toward my TVC rocket and doesnt have things like telemetry which I need. I main reused a lot of the schematic from the first version of the computer but I switched to an STM32H743VIT6 which was a bunch more gpio pins which I need, I also added a Ra-02 for telemtry, and has an ATGM336 gps, the imu and barometer is still the same as my old one, and it has multiple pyro and servo channels. Other than that I’m going to start doing to routing tmrw and I might do some to today maybe?
Other than that I’m going to start making the BOM and finalizing the Cad.

So today I planned out my overall idea for my rocket, I named it Hermes and this rocket will be used for both my L1 and L2 certifications. It is 1.7m in length, has a 34mm motor mount to hold a variety of motors and uses a dual deploy system.

A dual depoly system basically means that instead of releasing just on big parachute at apoggee and letting the rocket drift for that time, there initally is something called a drogue chute which is a small chute that only slow the rocket down adn minimzes drift, and after the rocket reaches a lower altitude it depolys the main parachutes(close to 100-120m).

The parachutes will be deployed using pyrotechnics, and will be timed with an onboard flight computer. Now I already have built a flight computer in the past that I could use for this flight, But that computer is still in the testing stages, so in the coming day’s im going to decide wheter I should just use that flight computer or get another seperate flight computer for redundancy.

The rocket will be made of a cardboard airframe and strengthened with an extra layer of fiberglass, This will probably be only for the main body and not the nose cone but I might also do it for the nose cone in the future. Beside that I’m going to have to figure out the flight computer dilema work more on bringing my stability caliber closer to 0 and beginning the Cad, and ya thats it.

So today I began assembling that actual flight computer, Most of the parts arrived a while ago but I only have time on weekends to work on projects because of school and plus im in my junior year right now. I took a while to plan everything out because I would only have around 2 hours until the solder paste dried so when I put the solder paste on I began speedrunning, Most of the components went smoothly but the really small capacitors were kinda annoying, I still have a bunch of resistors and capacitors I havent placed yet but I placed the majority of the main parts. I haven’t started assembly on the backside of the pcb so that will be next week. I also have some solder bridges on the stm32 chip and I bent one of the pins but I think I can rebend it so it should be fine.Also I realized that I had messed up during ordering one of the parts I had only ordered 5 of the resistors even though I needed 19, I dont know how I missed this but its alright because I had enough money left in my grant to buy the extra so that will also arrive next week and thats basically it.

(Also note to reviewer during my lapse for this session I left for around 30 minutes to eat lunch and forgot to pause so you can remove the time accoridngly if thats possible)

So today my 3d printed parts arrived which was awesome, My Body tube had also arrived a while before that so I got to assembling, I first started with the landing mount and assemebled using m3 screws, I used nylon for most of them and heat set inserts but I might switch to steel screws, I used some rubberbands I had lying around and tested wheter it works and it did kinda? there was a weird issue where the whole rocket tilted a little and put all the weight on 3 legs instead of 4, This was probably because of warp in the 3d print probably, I added some blue painter tape to the edges to help with this

Another thing I found was that the landing legs themselves acted as a spring, When you dropped it from a certain height or put enough pressure the leg itself bent. I actually like this accidental design because it helps with softer landings

The TVC mount was where I messed up. I realized that I hadn’t left space for the bottom y axis mount to move the way it should and structurally there were some issues also, to solve this I used a soldering iron to melt at the plastic and created a messy area for it the move and that helped pretty well, I have to redesign this in v2. Besides that I also forgot to tell my printer I needed my avionics bay printed and that I needed 2 tvc rockets not one, so i’ve decided that I’m going to focus more on getting one succesful flight up and parachute or do something like bps space did with echo and drop the rocket from a drone at high altitudue and try to land it (this is probably what im going to do). The rest of my parts are going arrive in the coming week but school also started so progress will be slow.

Today I worked on finalizing the bom, and I tidied up my repo, I added the old firmware I had coded with the flight computer but I’ll have to update it, I also came across this really weird issue with the pcb, last time I placed a fake order just to see the final price it came out to $350, but today somehow its 270? and also my shipping and customs alone are close to $100 which is crazy, I’m going to fix this pcb issue and submit but thats all, I also made a wiring diagram for the launchpad stuff

Edit: So I sent a question in the help channel and I decided that im going to be assembling the pcb my self, this will be much harder but it’s worth it for the cost savings.

Today was working mostly on my landing legs, I first got some inspiration from actual rockets like the falcon 9 and began designing. I first began by modeling the mount that will hold the legs and then worked on actual legs and struts, The main issues was making sure it fit proerly and wouldnt rub against the main ariframe, I made some cutouts in the landing mount to fit the servos, The landing legs will have rubber bands that act as spring and they will be held in the up position with a rubber band, Using a nichrome wire the rubber band will be heated and cut when I need it to deploy. Other than that the final steps will be making the wiring diagram for the launchpad updating github with my code and cad models. I also made a render with gemini that came out suprisingly well.

I did some small work today, I first began by making my own water deluge system, I first made a container that fits under the rocket launch pad and has a small sumersible water pump that pushes water directly under where the motors engine heat will be concentrated, I did this to mainly to lengthen the lifetime of the launchpad because after a certain number of launches this will probably just be too damaged. I also chose the uno r4 edition as my board that will control all my electronics, with this I can control the 2 servos, 2 esp32 cams,5 lights on the launchpad much easier and from a safer distance. I also did some BOM work and figured what parts I would need, I’m hoping this is an x tier project, the flight computer itself is coming out to $230 with shipping so I’ll have to find ways to save costs. The final steps are to make a BOM and finish up the landing legs.

Today was assembly day, I worked on first bringing all the parts together in onshape and I made sure to keep everything organized so its easier in the future for changes, I first began by making the rocket nose and tubing in onshape. I then got a 3d model of my flight controller pcb and made my own avionics bay for it, I made sure to leave space and areas for wiring. After that I began by making the complete assembly, I added the servos to the tvc mount and had to change some dimenions to make sure it fit properly, Then I made a full rocket model, and made sure to add the servos for the control arms on the launchpad. I ran into some dimensions issues but I went back and changed those pretty easily. I then got the lights and cameras in my cad.

I added 2 esp32 camera modules to the launchpad to record everything, I’m not sure if these will be fixed posistions ill probably move them around. I als added some WS2812 Breakout boards around the launchpad, and I also want to recreate the strobing red light effect thats used on the blue origin launchpad before it blew up, I didnt add the rgb strip light to the main strucutre yet and ill have to do that later. But that’s basically it, I’m also planning on adding aluminium protection on the flame trench just 5mm plates, and i’m going to add a small water pump to help out more with cooling. The final steps for this project will be making the BOM, writing the code, and finalizing cad.

Today I mainly focused on the TVC mount, There were many avalible models online and using them as refrence I created this, The mount uses sg90 tower servos, and m3 push rods. For the rocket motor I chose the F15 because it has a bunch of documentation on it and has a very predicatable thrust curve. I first began by modeling the motor mount and added a engine block at the top to prevent the motor from flying into the rocket. I then worked on the x and y axis and made sure that everythign was specced to the right dimensions to decrease slack. Other than that I also did some small work on the open rocket sim but didnt record like usual. The final steps will be to design the landing legs which will proably take the longest and finish up the launch pad, and create a full assembly.

Today I did some basic ground work. I first began by looking at my old flight computer I made this during blueprint but I never got to submitting which I don’t know why I didnt, beside that I added some silkscreen on the front and I’m going to add some on the back. After I began work on my rocket, So the main thing I had to think about was how the first and second motor ignition would work, I saw some examples like how joe barnard did with his scout e rocket but I had a diffrent idea. I split my rocket basically into 2 stages

The first stage has the ascent motor and is connected to the actual main rocket via a coupler, There is also a tvc mount for this stage which is connected to the flight computer via jumper wires. After the ascent motor is burned out the rocket reaches apoggee and starts coming back down and after a set time a pyro charge ignites the 2nd motor this will basically hot burn the first ascent stage off the rocket, To protect the first stage I’m going to add a thin aluminium bulkhead with a layer of some sort of heat insulation, and during the seperation The servo wires for the first stage tvc will just pull apart. I’m still thinking about wheter I will just let the first stage just fall or find a way for a parachute to fit safely, If anybody has some way I could bring it safely down I would love to here it, I’m going to start working on the landing legs soon and I need to work on a small emergency parachute for the first stage incase the motor doesnt light or the legs don’t come out as intended.

This is my first journal entry in what will probably be a really long project, My current plan for this project is to make a tvc rocket that can take off and land by itself, and make a custom launchpad with it. Today I just looked through my old flight computer model I had made and added some silkscreen I also think I’ll probably add a pyro charge to it? I also made rough cad modelling for my launch pad taking inspiration from bps space’s launch pads. I’m going to work a bit more today on the launch pad model and actually make itnto something like a real launchpad.

Cad work today, did some small refinments to the electronics bay and double checked that it would fit my motor driver pcb, my orignal version was too small, and thats basically it I did some other small cosmetic changes and I still have yet to change the diameter of the circles but ill do that soon, I’m going to begin working on a seperate project so I’ll try to wrap this up.

Today I worked on my Cad, The main thing that took way too long was the air vents, I made some 0.4in diameter holes and repeated them around the whole outer casing. I also added a place marker for where the aroma pad will be, I chose to put it in the center of the base so that when the fresh filtered air comes in and is pulled up, the scent naturally mixes. I also removed the place for the oled screen because I didnt need it anymore and fixed some small errors. The whole thing will be controlled online through esphome, So I’ll figure that out tommorow, Also these are the main parts
1)Esp32
2)Custom L289N motor Driver
3)DC Power
4)SPST
5)120mm Computer fan(2x)
6)Aroma Pads
7)M4 Heat Set Inserts and Screw

I also have to fix my cad to fit inserts because right now they are set at 4.1mm diameter holes, and I’ll work on my github

So hopefully today is the last day of pcb, I dmed Pero on slack who had very good experience with pcb and electronics and got some feedback on my drc errors. Most of them were small errors and after adding a capacitator I missed I fixed some small silkscreen errors also. Tommorow I’m going to finish my final cad, refine the project an submit for review, I’ve decided to drop the external enviorment monitor part of the project for simplicity but I’m still working on it and I’m going to make a seperate project for it in the coming days.