I added a new step to my project that wasn’t in the original plan: painting. Gotta improvise sometimes.
before
With the old plywood doors removed and the new door and frame installed, the shed was looking much classier. But that part of the project required framing the new door properly, filling in new gaps with plywood, and caulking between the plywood sheets to seal it up. Basically, this left a bit of a mess, as you can see above.
In addition, the new door frame was just bare wood, without any paint or stain to cover and protect it. This would need to be painted not just for cosmetic reasons, but for longer term protection.
after – newly painted
As for the rest of the shed, a new coat of paint will always clean things up. Besides, it had been a few years and was probably due for a new coat anyway. With nearly constant rainfall in the Seattle area all year round, exterior surfaces really take a beating from the weather.
The most difficult part of this phase wasn’t the painting at all – that was simple enough, and fun. It was trying to come as close as possible to matching the exact shade of blue here. To be fair, it didn’t need to match precisely, especially if I were going to re-paint the entire shed anyway. But our house was painted with the same color blue as well, and ideally the shed should continue to match the house.
pre-paint job
So after half a dozen trips back and forth to Home Depot and a ridiculous number of paint chips, I was finally able to match the color. Much to my surprise, it’s not blue at all, but actually called “Sheffield Gray,” at least according to the paint’s official label.
The white paint for the door frame/ trim was a lot easier, and it didn’t matter quite as much whether it matched. I’m actually still torn about this color even after painting the frame because the house uses more of a gray color for the trim around all of the doors and windows. But hey, white looks nice too.
post paint job
As mentioned above, the painting work itself is straightforward and actually fairly enjoyable. The exterior of the shed is not a particularly large surface area, and it’s not difficult to reach any area, so I didn’t even need a ladder or any tools other than a simple brush (and a screwdriver to pry open the paint can lid, and a hammer to shut it again).
If only the entire shed-to-workshop transformation project were this easy.
I was originally going to create a series of articles dedicated to this topic: building an electronics bay for a rocket. Having never done this before, and having no idea what I was doing when I began, it took me quite a while to figure everything out and to actually build this thing.
In the end I decided nobody cares how long it took me to do this, and everyone is better off with a summary, even if it’s a slightly lengthy one. Quick table of contents based on the section titles below:
Why am I here?
What you’ll need
More about the flight computer
Step 1: Decisions and planning
Step 2: Attaching the components
Step 3: Dual deployment capabilities (optional)
Final thoughts
Why am I here?
So to get started: I’ve covered in a few previous posts what an electronics bay (or “e-bay”) is, and why you might want to build one. Just to recap here, an e-bay is not strictly necessary to launch a rocket, but it lets you do a variety of cool things. For example, with the right electronics, you can measure and record exactly how high your rocket goes; fire charges to deploy one (or two!) parachutes with more precision during the flight; track its location after it disappears from sight and inexplicably lands far away; and much more.
flight computer
But assuming you already know what an e-bay is and some of the cool things you can do with one, the next step is building it.
What you’ll need
There are a lot of different ways to go about doing this. A simple e-bay can have minimal components. For example:
an altimeter to measure the rocket’s maximum height (it actually measures barometric pressure and uses that info to deduce the height);
a battery; and
an on/off switch.
That’s it, for the main components. In addition, you’ll need:
copper wire to physically connect things together (if your switch doesn’t already come with wires); and
some way to secure everything in place during flight (e.g. screws, or glue, etc.).
This last bullet can include nylon screws and washers (which I used for the flight computer), or just a lot of glue, or rubber bands or zip ties… you can get creative.
This simple e-bay wouldn’t have any ability to communicate wirelessly with things outside of the rocket, but it doesn’t need to. As long as you can locate your rocket post-flight and remove the e-bay and altimeter, it will provide you with useful data.
You can also go toward the other end of the spectrum and make the electronics as complicated as you want. But the basic concept is the same. You have at least one circuit board or flight computer, powered by at least one battery and connected to an on/off switch.
More about the flight computer
I chose to start with the TeleMetrum, which is a flight computer from Altus Metrum. It combines the functions of an altimeter with a few other abilities, including firing two separate pyro charges (for dual parachute deployment), GPS tracking, and a radio transmitter – hence the long antenna.
Physically, the TeleMetrum is just 1 inch wide by 2 3/4 inches long. It’s amazing how much cool tech can be crammed into such a small board. The antenna is 7 inches long, and ideally for this particular board you’d want an e-bay with at least 10 inches of interior length to accommodate the board and antenna. My e-bay was less than 8 inches, though, so I needed to extend the antenna somewhat outside of the actual e-bay. The antenna is flexible wire, but it’s best to keep it as straight as possible.
e-bay mid-construction
I’ve also previously posted about building the e-bay minus any of the electronics, so I’ll just skip ahead here, assuming you have already constructed an empty e-bay based on my spectacular instructions and are ready to add all of the fancy gadgets and components.
Step 1: Decisions and planning
As noted above, you’ll need to first decide exactly what you want in your e-bay. Do you just want a simple altimeter to measure height? Do you need to fire pyro charges to be able to do dual deployment? Do you want GPS tracking and radio communication with your rocket?
For my purposes, I wanted all of the above, which is why I selected the TeleMetrum after carefully reviewing the options.
I also got a rechargeable 900 mAh LiPo battery from Altus Metrum. It’s really small and lightweight. Finally, I got an unnecessarily large push-button on/off switch, and some 20 awg copper wire from Home Depot. As a side note, “awg” technically stands for American wire gauge, but this would typically be referred to as “twenty gauge wire.” Somewhat counter-intuitively, the larger the gauge number, the smaller or thinner the wire diameter. The one I bought, 20 awg, is sometimes called “bell wire” because it’s used for common household purposes that require small amounts of current, like doorbells or buzzers.
e-bay nearly complete
You can see from the pictures above how I placed the components in my e-bay. Simple, right? To be honest, I’d say at least 95 percent of this is just planning and understanding what you’re doing – making sure you have all the right parts, you understand how everything works together, and where exactly it will be placed. Once the planning is done, the rest is a piece of cake.
Step 2: Attaching the components
To attach the flight computer, which has pre-drilled holes right in the circuit board, I drilled 4 holes in the e-bay wooden “sled” and used 4 nylon screws. I also added a dab of epoxy to hold them in place, just in case. I’ve actually heard that nylon screws work really well for this purpose, because they will shear. If the rocket suffers a catastrophic failure or really rough landing, the impact may shear the nylon screws (which absorb most or all of the force), but preserve the flight computer intact. I don’t plan to test this out, but it can’t hurt.
The push-button switch I simply glued in place with epoxy. It’s important to note that you’ll also need to drill a small hole through the external wall of the e-bay, and that hole should line up with the switch. You should be able to push the button – and therefore arm or disarm your rocket’s flight computer and electronics – from outside the rocket by simply inserting a pencil, screwdriver, or other small thin object through the hole to push the button. Make sure the hole lines up with the switch!
Finally, to help secure both the switch and the battery in place, I cut a few very small pieces of wood and secured them using wood glue. This isn’t strictly necessary, but it helps give extra security to the switch, and keeps the battery from moving around. I also used a zip tie with the battery, which I can cut if I needed to remove or replace the battery – though that isn’t likely.
e-bay view of one end cap
Depending on what kind of electronics you’ve chosen and/or what you want to do with your flight computer, you might be done at this point. If you just have a simple altimeter, or you aren’t interested in dual deployment (yet), you now have a finished e-bay. Congrats!
However, if you are interested in dual deployment, or you just enjoy exposing yourself to dangerous materials and explosions, read on.
Step 3: Dual deployment capabilities (optional)
For dual deployment, you’ll need – in addition to the above list – the following things:
two small (1 inch) PVC pipe end caps;
some small screws and matching washers;
black powder (recommend FFFF); and
electronic matches (“e-matches”) or electronic igniter, such as the MJG Firewire Initiator.
In addition, while not strictly necessary, you may find it helpful to also have:
two 2-way barrier strips; and
at least one 4-circuit male connector and one 4-circuit female connector.
the underside
You can see a white PVC pipe end cap and white two-way barrier strip in the photos above. One of each is attached on the outside of the e-bay, on each end, and they’re secured by drilling a hole, using a screw and washer, and also adding a few dabs of epoxy for good measure to hold everything in place.
The PVC pipe end cap will hold a small quantity of black powder, which will give you your explosive charge, separating the two parts of your rocket at the appropriate time and deploying your parachute. The black powder is ignited with the e-match, which is wired up to the flight computer (which tells it when to activate).
The reason for the barrier strip is to connect the e-match to the flight computer without having to disassemble everything every single time – it’s just more efficient to have permanent wires running from the flight computer to the barrier strip (which, again, is located on the outside of the e-bay for convenience), and to just be able to swap out the e-match more easily each time.
Similarly, the reason for the 4-circuit male and female connectors is just to more easily be able to pull your e-bay out and access things inside. With the connectors, you can simply disconnect the wire and pull things apart much more easily, and you can also use a shorter amount of total wire which takes up less space and doesn’t clutter up the inside as much.
finished e-bay!
Final thoughts
In this last picture, you can see the overall build of my e-bay. It’s nothing special to look at, but hey – it’s my first one. I also thought it was important to leave as much additional space as possible in case I want to add more electronics later, either for redundancy or to provide new capabilities for the rocket (GoPro camera anyone?). But your layout is up to you.
If all goes well, this whole setup will allow me to do much more in high power rocketry and accomplish a variety of goals I’ve set for myself in 2020.
A few final thoughts and some helpful tips:
Plan. As mentioned above, most of the work here is just planning and understanding what you’re trying to do, and ensuring you have the right parts. Once you’ve solved for all of that, building is the easy part.
Glue. When in doubt, use more wood glue or epoxy, not less. You can secure the components many different ways and have a lot of options.
Layout. Leave room for additional future components (if you have the space for it). If not, no worries.
Get creative. My antenna didn’t quite fit within the e-bay so I drilled a small hole to let it poke outside. And since it’s kind of close to explosive black powder, I shielded it with part of a plastic straw.
Label everything. It’s good to sketch out what you’re trying to do ahead of time, and it’s also helpful to label parts as you go. You can see, for example, I wrote “TOP” with an arrow on the outside of the e-bay to make sure it’s inserted into the rocket body the right way. Once the e-bay is completely sealed up, it’s not always easy to remember which way is up!
Next up, I have some ground testing to do – before sending this thing thousands of feet into the air.
You know what they say: when god closes one door, he opens another. Right?
I was googling to find the exact phrase (and its original source) and apparently one of the most popular google searches along these lines is “when god closes all doors.” If that happens, you should be very concerned. It’s definitely a bad sign.
For example, the room can suddenly erupt in a fiery inferno, and if god has closed all doors, how are you going to escape? You need an emergency exit. And if one doesn’t exist, you may need to build it yourself.
This, then, is the story of me building my own emergency exit to escape the inevitable fire and billowing black smoke that is sure to occur in the near future: aka, installing a door.
plywood doors + padlock. not super inviting
Our mundane garden shed came with what might generously be described as French doors. Generously would be the key word, here, because the doors are cheap, made of nothing other than thin plywood, and completely windowless. There’s no handle per se, but a nice metal padlock secures the structure from unwanted intrusion.
This phase of the shed-to-workshop project calls for the complete removal of these doors, and replacing them with a real door.
As with the windows, a lot of this is just measuring and planning. I considered putting in double doors (real non-plywood ones), but this is actually kind of a narrow space for that – the opening is only about 48 inches wide. On the other hand, that’s too wide for a single standard door, whose width is generally 36 inches. I decided to go with a single door and just put in a new wooden frame to accommodate it.
The height is also unusual here. A standard door would be approximately 78 to 80 inches in height, but the opening here with the plywood doors removed is only about 60 inches. Yes, that’s only five feet, meaning I have to duck to enter or exit, no matter what kind of door I use. It is a shed, after all.
In the end, I decided to get a fiberglass door, cut to a custom shorter height, with a large glass window to let in more natural light.
With the decisions made and planning complete, I placed an order for the door at a local shop, which includes the door jamb (i.e., the wooden part around the sides and top of the door). It arrived about a week later; in the meantime, I also picked up a heavy duty external locking door handle from Home Depot. As with the windows, I enlisted some help in removing the old plywood doors, framing and installing this new door.
a legit door. much classier!
But it’s finally done! You can see where the old plywood doors had been, and where their hinges had been attached. We were able to repurpose some of the plywood from the old doors to fill in the gap (since the new door is narrower), caulking to fill in the spaces.
Of course, this still needs some additional work to finish and clean it up. I’ll need to paint the entire front wall blue again, which will first require matching the exact shade of blue and buying the paint. And I’ll also need to paint the wood trim around the door, something like white or grey.
workshop starting to take shape, at least externally
But cleaning up and painting is no big deal. The hard part is over, and the place has a nice new door! A proper emergency exit, which you can be sure I’ll use during an upcoming welding mishap or rocket engine explosion.
The workshop is coming along nicely. I think the next step will be to get a butcher block countertop and install that inside so I have a nice large workbench for rocket projects.
Defenestration (n). The act of throwing someone or something out of a window.
a classic and memorable defenestration
In particular, the Defenestration of Prague in 1618 involved some angry folks tossing several government officials out of a window from Prague Castle. Generally, when you have unwanted guests and you’d like them to leave, the preferred approach is to drop subtle hints that you need to wake up early the next morning, or start cleaning up. Maybe turn on a vacuum if they don’t get the hint. A forcible ejection through the window can have the immediate desired effect but may ultimately lead to a long and terrible war (in that case, the Thirty Years’ War).
Speaking of forcible ejections through the window, many things can go wrong when building or using a workshop, and I named each phase of my shed-to-workshop project after a small sample of them. In this “defenestration” phase, I’ll add windows to the shed.
taking this shed to the next level
First, I had to plan a bit: how many windows? And how large should they be? Of course, I want to maximize light, and my initial answers were more windows and bigger windows, respectively. But more windows cost more money and are significantly more work to install. And most importantly, there’s only so much room inside to actually use or store tools and equipment, and windows eat up some otherwise useful wall space.
Two windows seemed sufficient to really open up the space and provide ample natural light. I thought one on the side and one on the back wall made the most sense.
A shed would typically have pretty small windows, too, something like 12×24 inches or maybe 12×36. Larger would always be better, but then again, I didn’t want the windows to look ridiculously oversized on such a small structure. I ended up going with two windows that are each 24×48 inches.
The walls here are just simple plywood, so after the initial planning was done, this project required:
measuring and cutting away the plywood rectangles where windows would go;
cutting some wood and framing the window; and
installing the window itself, along with some flashing.
Overall nothing too crazy, but a decent amount of work. I did have someone help me with this project; I’m ambitious but only mildly handy, and certainly not an expert.
let there be light!
And this is the finished product! It’s amazing how much a window or two can transform a room. It looks like a completely different space, flooded with light. It even feels bigger, and is the type of place I wouldn’t mind spending an afternoon working on a rocket build or some other project, especially in the spring and summer once the weather gets nicer.
On to the next step: replacing the plywood shed doors with a real door. Something to help class it up, maybe with some glass to add even more natural light. And a handle, ideally, to open and close this door. Maybe I’m going too far? One can always dream.
As I’ve mentioned before, I have an uninspiring simple garden shed in the back yard, and one of my goals for 2020 is to convert it into a workshop, primarily for rocket construction and related projects.
the eponymous shed
The shed is in good condition, though it’s only a small space, with an area of approximately 10×10 feet. It currently has crude plywood doors and a padlock, no windows or source of light, and it’s full of old junk, ranging from bulky A/C window units to a variety of leftover materials from the previous homeowners and contractors. Extra brooms, lumber, carpet, pipes, empty beer cans – you name it. There is also a layer of dust covering everything, seemingly several inches thick and whose only explanation can be a recent volcanic eruption nearby.
partial progress
This is kind of a big project, so I’ve broken it down into a few major steps. Each of these has its own sub-steps, but I’ll spare you that level of excruciating detail and just leave it in my own personal to-do list. The major steps basically include:
The Purging. Remove and haul away junk inside the shed, and clean it up.
The Defenestration. Remove portions of walls, frame new windows, and install windows.
The Emergency Exit. Remove old plywood doors, frame new door, and install door.
The Butchering. Buy new butcher block countertop for a work surface, stain and seal it, and install.
The Electrocution. Add electrical panel and wiring (running a line from the house) for light fixtures and outlets.
I’ll probably write a separate post for each of these steps, as I complete it. Starting with #1 here.
Long story short: I took some junk out of the shed and cleaned it up a bit. That’s it.
what is all of this?
This is not particularly fascinating, but it’s kind of fundamental to completing the rest of the process, and to properly document this, I needed to start at the beginning. The previous owners of our house had hired some contractors to do quite a bit of renovation, and as mentioned above, they seem to have left a virtual treasure trove of useless junk in the shed. I got rid of as much as I could, though there’s still a bit left that I need to remove in order to complete the purge. Perhaps I’ll come across a rare antique, or a box full of cash.
But if nothing else, an empty clean shed is a blank canvas. It’s structurally sound, and it was built fairly recently and even has a new roof. Next I’ll add some natural light and really open it up.
Success! I officially have my amateur radio license.
Of course, you might be asking: what does this have to do with rockets? A fine question.
a fancy mobile amateur radio
One of my goals for 2020 was to get an amateur radio (aka “ham radio”) license from the FCC. I knew literally nothing about ham radio, and I still know exceedingly little. But as I started learning more about the electronics in rockets, I discovered that you are legally required to have this license in order to use certain flight computers, such as the one I bought and recently installed (the TeleMetrum, from Altus Metrum) in my electronics bay, since you are transmitting via radio. And even if it weren’t strictly required, it would certainly be helpful to know some basics about electronics and radio waves.
Just as an aside, rocketry is an even better hobby than I initially thought it’d be. It really requires you to learn not only about different aspects of rockets, but also a lot of the basics in many rocketry-adjacent fields.
What am I talking about? Well, this is a good example: in this case, I discovered amateur radio. Prior to this, I hadn’t really given it much thought. But given that electricity and radio waves are the foundation of our entire modern technological society, it doesn’t hurt to know a bit more about it.
I’ll probably put together a separate post just on some of the content required for the exam, a sort of amateur radio 101, but just as an example: I hadn’t realized that cell phones and wifi are simply ultra high frequency (“UHF”) radio waves, fundamentally the same thing as VHF and UHF broadcast television channels or AM and FM radio channels. Some of this was pretty interesting stuff, although other areas just involved rote memorization.
Anyway, there are three levels for the amateur radio licensing exam. The FCC officially manages this entire process but farms it out to local clubs across the country and their volunteer examiners. You can apply for the following types of licenses:
Technician
General
Extra
Each license requires passing an exam that is progressively more difficult, but each entitles you to additional rights and privileges when using amateur radio frequencies. Everyone who gets any amateur license is also assigned a unique “call sign” by the FCC, some combination of letters and numbers, often starting with a W or K (which is also why radio and TV stations have these broadcasting abbreviations, like WJMK or KSCS).
exciting weekend reading
I studied for the technician license and (fortunately) passed that exam, in Redmond, WA through the Lake Washington Ham Club. I took out a few books from my local library and studied for a weekend, taking some practice exams online.
I only really need the technician license, so I’ve checked that box and can bring my focus back to rocketry, but I could see potentially taking the additional exams for the general or extra class down the road at some point. That said, it would require a significant amount of additional studying.
So long story short, the FCC notified me that my license was granted and assigned me a unique call sign: KJ7LRF.
Now to complete the electronics bay for my rocket – and I can finally begin using this flight computer.
I recently had a chance to visit the Museum of Flight in Seattle for the first time – long overdue, in fact, since we moved out to the area more than 18 months ago. It was an impressive place with some great exhibits. In particular, we spent most of the time in the Charles Simonyi Space Gallery, although there was much more to see.
One highlight was an actual module from a Soyuz spacecraft. Soyuz was the human spaceflight program in the Soviet Union (and continues today in Russia), and the Soyuz rocket and spacecraft were integral parts of this program. Interestingly, the Soyuz rocket is the most reliable launch vehicle, as well as the most frequently used launch vehicle, in the world. The first Soyuz manned capsule was used in 1967, and Soyuz flights have taken place more than 1,700 times since then, in both manned and unmanned missions.
The Hubble telescope
The exhibit also had some life-size models of things like the Hubble telescope and even a life-size space shuttle that you can climb aboard. Pictures (such as the Hubble, above) obviously don’t do the size of these things justice, although the relatively small floating astronaut next to the telescope helps provide a sense of scale.
The Hubble telescope is of course extremely well known. It was launched into low earth orbit in 1990 and remains in operation today – 30 years later! – and it’s produced countless amazing images of the cosmos.
One thing that I didn’t know was that the Hubble is expected to last until 2030, or perhaps as late as 2040, and that its successor is the James Webb Space Telescope, scheduled to be launched in 2021 – from an Ariane 5 rocket. What a time to be alive!
Rocket Science 101
The space gallery also had a variety of other exhibits, including some interesting info about how rockets work, differences between solid and liquid fuel rockets, and displays related to the world’s largest rockets and orbits. I’m no expert on any of this, and I really enjoyed this “Rocket Science 101.”
I only included a handful of pictures here, but for more, you can check out my Instagram.
The Museum of Flight really has a lot of other exhibits to see as well; in fact, it’s primarily dedicated to aviation and airplanes (e.g. from the early days of flight and the World War I and II era), with only a smaller space dedicated to spacecraft and rocketry. But it’s absolutely worth a visit, whether you live in Seattle or next time you’re visiting.
The rocket construction is complete, but there’s one minor issue I still need to address. The rocket has a 54mm motor mount tube, meaning I need a 54mm diameter motor to fit inside. But I couldn’t find any H or I level motors (note: for the level 1 certification flight, the motor must be an H or I) that are 54mm. I could only find 38mm motors.
ENTER: THE MOTOR ADAPTER.
adequate adapter
The motor adapter is exactly what it sounds like. It allows you to adapt a motor of a given size to a differently sized rocket.
You can always use a smaller diameter motor in a larger rocket as long as you get an appropriate adapter; in my case, I just need a 38 to 54mm adapter. It’s like using a booster seat at a table if you’re too small for the seat. (Important corollary: if your motor’s diameter is too large for your rocket, you’re simply out of luck, and at that point you just need to build a bigger rocket.)
The rocket is made from durable and reinforced cardboard, so I figured a cardboard motor adapter would be sufficient. And it probably would be, but I wasn’t satisfied.
indestructible adapter
The cardboard adapter was extremely durable and fit perfectly. I had no doubt it would keep the motor properly centered. The only issue was retaining the motor – i.e., keeping it from falling out the bottom of the rocket. And not just falling, but forcibly ejecting out the bottom after the motor has burned through all its propellant and the explosive ejection charge happens at the other end.
I’ve explained this before but just to recap the serious danger: ideally the motor stays put, and the hot explosive gas at apogee forces the rocket sections apart (deploying a parachute). But if the motor isn’t properly secured, what can happen instead is the motor itself ejects and falls out the bottom. That’s bad. Even worse is the fact that the rocket didn’t separate as a result, and the parachute didn’t deploy, meaning now the entire rocket will come crashing down.
Retaining the motor is a big deal.
I did try attaching some small metal retaining clips, but I wasn’t confident they would hold under extreme conditions.
In light of this concern, I upgraded to a machined aluminum adapter. It’s more expensive, but the primary advantage here is that it looks fancier. Also, this adapter has its own retainer, so there’s no worrying about the motor ejecting out the bottom at apogee. Things will work as intended!
The business end of a rocket
One other nice feature is that the 38mm adapter and its retainer fit perfectly inside the larger 54mm retainer. This allows both to be used at the same time for smaller motors, or alternatively, the adapter can easily be removed and the 54mm retainer can be used solo for larger motors.
I think I’ve exhausted this topic. In summary, metal > cardboard, and retainer > no retainer.
As I get more into building larger rockets, I’ve been increasingly aware of the limitations of my work area. Specifically, I don’t have one. We have a fairly small house and there’s no dedicated space for gluing or drilling or doing anything with large parts. I’ve had to temporarily co-opt our dining table.
We do, however, have a mundane shed in the backyard. It’s in good shape, but it’s dark and dirty, with no windows or any natural light, no electricity, and is generally just full of old junk that came with the house. But it has potential.
Run of the mill shed
I decided one of my goals for 2020 is to convert this shed into a useful workshop, primarily for rocket-related projects. This is just the first of a series of posts documenting the process of transformation and the resulting workshop.
This is kind of a big project, so I’m breaking it down into a few major concepts or steps:
Remove junk & clean.
Install windows.
Replace door.
Install new countertop work surface.
Add electrical wiring for light fixtures and outlets.
This isn’t necessarily a comprehensive list, but I think that once I complete each of these parts of the project, it’ll go a long way towards making this a practical (and really cool) workshop. And then I’ll give it a name to class it up, like the Rocketshop.
I’m getting all the parts together to build an electronics bay for my first high power rocket. Totally winging it here.
An electronics bay in a rocket, capable of dual deployment of parachutes, requires a couple of things: a flight computer or some similar electronic chip; a battery to power the chip; an electric match or igniter; and some explosive black powder. And, of course, some additional cords and pieces needed to wire everything together properly.
The basic idea is that the flight computer activates a “pyro charge” at the appropriate time. This electrically ignites the match, which in turn creates a spark inside some very tightly packed black powder. Which explodes – with some real verve.
It’s not as crazy as it sounds. The explosion and resulting expansion of hot gases causes the rocket body to separate at a pre-planned location, and a parachute deploys, assuming all goes well.
red end goes bang
This is a “firewire initiator” from MJG Technologies. In other words, it’s an electric match.
Apparently the federal Bureau of Alcohol, Tobacco, Firearms, and Explosives (“ATF“) generally regulates electric matches and igniters, but this is the only non-regulated version on the market. It’s made specifically for rocketry.
I previously uploaded a quick video of me testing one of these, but the real fun will be combining it with the compressed black powder, for one of your more vigorous explosions. Stay tuned for more ground testing.
Improbable Ventures 