Jeremy Jones/Builder & entrepreneur/Aspiring finance major
I'm a high school senior in Maryland. My work ranges from a cross-platform student planner to a profitable vending business and a wearable cooling prototype.
Wearable CO₂ cooling for the first minutes after an injury. Van Eney '09 Fellow.
Baltimore · since winter 2024
Monthly revenue · $600+ profit
U.S. companies ranked by return on capital and earnings yield.
A $5-a-month subscription app for running college applications: every school's requirements, progress, and deadlines in one place.
weekly tutoring clients
free finance sessions taught
Personal finance app I taught with at Harvard's summer program.
Populations of AI agents paper-trade, get scored on fitness, and are culled and mutated each generation.
A complete personal finance guide for teens. Every topic drafted.
A Chrome extension that takes meeting notes in Google Meet.
A desktop study app that runs on Claude through the Claude CLI.
Severn Planner for Mac and iPhone, plus eight Mac utilities I built for my own use: a screen recorder, a dictation app, a file shelf, and five smaller tools. Closeup and Ledge are open source.
A planner that reads a student's assignments and free time, then schedules the studying. I started it in early 2025. It now connects to ten school platforms and runs on the web, as a Chrome extension, and as native Mac and iPhone apps.
I built it alone, from the first web version to the native Mac and iPhone apps, and I handle support and marketing too. I wrote the first version by hand and now build most of it with Claude Code.
School platforms it connects to. Live on the web and the Chrome Web Store, and the iPhone app passed Apple's App Review in November 2026.
Each assignment gets fit into the time a student actually has, with breaks, long work split into sittings, and a replan when they fall behind.
Class periods, commitments, and study sessions share one calendar. A group-time finder picks a slot that works for a whole study group.
Category weights for every class, weighted and unweighted GPA, and a predictor for the score needed on the next test.
Daily streaks with a freeze, eight weeks of study time, and personal goals that get planned around school.
After a quiz it asks if prep was enough, and that answer sizes the next one.
Spots a test, project, and essay landing together and moves work earlier.
"History essay Friday 1h" fills in the class, date, and length. A whole syllabus can be pasted at once.
An optional passphrase encrypts the planner with AES-256 before it saves, so the server only stores scrambled text.
Blackbaud, Canvas, Schoology, and Google Classroom, matched to the right class. Duplicates are skipped.
Splits each test into short review sessions leading up to test day.
Paste a whole list and every assignment comes in with its date, type, and class.
Shows what a student needs on the rest of the work to finish a class with the grade they want.
Friends share when they're free, and it finds a time that works for the whole group.
A recap of the week's study time and finished work, then one tap to plan the next week.
The core. Runs in any browser and plans the studying.
Pulls assignments and grades straight from the school site.
Lives in the menu bar and syncs school by itself.
The live planner in a native app, with iPhone features around it.
The iPhone app has been approved by Apple's App Review, and the Mac app is signed and notarized by Apple. Anyone can also add the web app to the Home Screen from Safari. On iPad it adds a Desk mode and a floating Picture in Picture timer.
It never sees a school password, and it only reads from Google Classroom. Canvas can also connect with an access token, with no extension.
Review sessions get added after a quiz or test, each linked back to it with a recall exercise to do.
Mark a question to ask the teacher. It goes on the schedule, and study time for it waits until after that class.
A note on what went wrong on a quiz, plus time estimates that learn from how long past quizzes actually took.
Presets, breaks, a stopwatch, and Spotify. It can pop out over other windows, and logged time counts toward the weekly review.
Distracting sites pause while the timer runs and come back when it ends or a break starts.
A shareable card with the week's streak, hours studied, assignments done, and top class.
Today keeps only what's due tomorrow, the rest moves later in the week, and there's a button to email each teacher.
Share a class's upcoming dates as one link. Classmates can add them without an account, and grades and notes stay private.
Goals like running three times a week get booked first. Skip one for a week without breaking its streak.
A wearable cooling system for the first minutes after an injury, which I'm designing and building as a Van Eney '09 Fellow with an in-school and an out-of-school mentor.
A backpack unit uses CO₂ to chill a fluid loop, and a silicone sleeve carries that cold to the skin. CO₂ never touches the body. A skin probe closes the control loop, and three fault conditions latch the system off until someone resets it by hand.
I design, build, and test it myself as a Van Eney '09 Fellow, with an in-school mentor and an outside mentor.
Parts are in, and I'm fabricating the CO₂ engine now. Thermal phantom testing comes next, ahead of a panel presentation in February 2027.
I worked through the literature on targeted cooling and hypothermia therapy, which turned out to be deeper than I expected, and decided to add phase change materials (PCMs) so the CO₂ system doesn't carry the whole cooling load. Most of the parts list is off the shelf: regulators, solenoid valves, temperature sensors, and an Arduino.
At Harvard's summer program I reviewed the thermodynamics behind the build and talked through whether PCMs were feasible with my professor. Back home, the first parts had arrived, including a blood pressure cuff to test nozzle sizes and how to move pressurized air.
I tore down a blood pressure cuff to see how a small pump, valve, and air line fit together, started a course on the Arduino Uno that will run the device, and wrote up the engineering theory and calculations. I chose an armband for the first prototype so I could learn the technology before building a vest or helmet.
The system architecture doc got corrupted, so I rebuilt it from scratch, and cut two parts that didn't fit a CO₂ and PCM design. I modeled the electronics enclosure and a 280-degree armband shell around a 48 mm bicep radius, and caught that silicone tubing only works after the regulator. The tank-to-regulator line needs a CGA-320 rated hose. Safety gear went on order too: cryo gloves, a CO₂ monitor, a face shield, and a wire cage to pressure-test inside.
After testing, I changed the core design. Instead of CO₂ snow cooling the skin directly, it now chills water in one small metal chamber, and the water carries the cold to the body. High-pressure expansion stays inside that chamber, which removes the risk of frostbite or a blowout against the skin, and should be cheaper to make and more efficient.
The parts are in and the physical build is underway, starting with the CO₂ engine for the Phase 1 armband.
Moving the high-pressure CO₂ into one sealed chamber keeps it away from the body entirely, instead of trying to shield the skin from it.
The Peltier module and vacuum pump looked useful on paper, but neither belonged in a CO₂ and PCM system.
The same tubing can't go on both sides of a regulator. The high-pressure side needs a CGA-320 rated hose.
An armband is the cheapest place to learn the cooling and the fabrication before a vest or helmet.
The machines in a renovated industrial building were rusted and broken. I pitched the owner, won the placement, and bought my own machine with tutoring profits and most of my savings. Then I tuned pricing and the product mix until profit topped out, going from about $100 the first month to more than $600 a month.
All of it. I spotted the broken machines, pitched the building owner, paid for my own machine, and I handle stocking and pricing.
Monthly profit, from about $100 in the first month to more than $600, on over $1,000 a month in revenue.
The building's tenants. I set the mix and the prices around what they buy, and kept adjusting both until profit leveled off at about $600 a month.
In-person math tutoring at the Severna Park library, priced below local services, with 10 clients a week. Through it I also taught six free personal finance sessions on taxes, budgeting, saving, and credit.
Founder and the only tutor. I set the prices, built the website and sign-up, and teach every session.
Weekly clients, from 5 to 10.
A paid app for running college applications: what each school requires, how far along a student is, and every deadline in one place. It covers the whole application, from the school list to essays, activities, and scholarships.
Built with React, TypeScript, and Firebase, with Stripe billing and on-device encryption.
I built it alone, including Stripe billing, and checked every school's deadlines myself.
Live with Stripe billing and a 7-day free trial, covering 2,560 four-year U.S. colleges.
One card per school, in that school's colors, with what it still needs.
A page per school with the full checklist and its own task list.
A word processor built into the app, for the personal statement and every supplement.
Every school on a map, and every date in one line.
The parts of an application that aren't tied to one school.
Screens are from a demo copy filled with example schools and sample entries.
Search 2,500+ colleges by name or nickname, like UPenn or NYU, or paste a whole list to add several at once.
Put top choices in order and the dashboard lists them first. A Chrome extension can also read a school list off an open Common App tab.
Stripe Checkout and Customer Portal through Netlify functions. Firestore rules enforce the paywall on every write.
AES-256-GCM with a key wrapped by a passphrase (PBKDF2, 600,000 rounds) and a recovery code.
School list and stats from the federal IPEDS dataset, plus hand-checked deadlines, platforms, and supplements.
Light and dark themes, a phone layout with a tab bar, backups, and sync across devices.
Ranks every listed U.S. company by return on capital and earnings yield, following Joel Greenblatt's Magic Formula, with guards for thin capital, one-off earnings, and sector concentration.
Tracks accounts, budgets, goals, and recurring payments. I built it at the start of summer 2026 and gave it to my class when I taught a personal finance session at the Harvard summer program.
Checking, savings, cash, investments, and debts like a credit card, which turn the total into net worth.
A monthly limit per category that shows whether spending is on track for the month, and flags one that runs over.
Savings goals with the monthly amount needed by the deadline, and paychecks, bills, and transfers that post themselves.
Projected spending for the month, the savings rate against a goal, and the biggest expenses, written out in plain sentences.
Quick add understands "coffee 4.50". Bank exports import as CSV, OFX, QFX, or spreadsheets, and rules sort them into categories.
Income, spending, and savings rate by month, with a running net for the year.
Data is stored a month at a time, and edits from two devices merge record by record instead of overwriting each other.
Installs to a phone's Home Screen, with dark mode, a hide-amounts switch, and export and backup.
Balances across every account, plus the month's income, spending, savings, and how each budget is pacing.
Every transaction, searchable and filtered by type, account, and category. Bank files import as CSV, OFX, or spreadsheets.
A monthly limit per category, flagged when one runs over.
Savings goals with the monthly amount needed to hit each deadline.
Income, spending, and savings rate by month, with a running net for the year.
Paychecks, bills, and transfers that post themselves on their due date.
Everything here is native Swift and SwiftUI: Severn Planner for Mac and iPhone, plus eight Mac utilities I built for my own use, from a screen recorder with automatic zooms and a voice dictation app to menu bar tools and a Quick Look extension.
Closeup and Ledge are open source on GitHub.
Screen recordings that look edited.
A drag-and-drop shelf for the Mac.
Nearly everything Wispr Flow does, running on the Mac.
Copy text from anything on screen.
Claude plan usage at a glance.
Cut and paste for files in Finder.
Keeps the Downloads folder tidy.
See inside a folder or zip with the space bar.
Competitions, programs, and teaching.