The Bluetooth book
It won't pair.
It sends garbage.
It won't talk to your iPhone.
Every way an Arduino Bluetooth link fails, why it fails, and the fix — for HC-05, HC-06, HM-10 and the clones sold under all three names.
62 pages. Written to be opened in the middle, at the moment something stopped working.
Page 2
It opens on what is actually wrong
Most books make you read from the start. This one has a symptom index on page two, written in the words you would use to describe the problem — not the words an engineer would use to classify it.
- →It never appears in my phone's Bluetooth list
- →It pairs, then drops after a few seconds
- →The Serial Monitor shows nothing but garbage
- →Uploading a sketch hangs forever
- →AT commands return ERROR, or nothing at all
- →It works on Android but my iPhone cannot see it
- →Half the AT commands in the tutorial do not exist on my module
- →The module got hot, and now it is dead
Why this book exists
You may not own the module you think you own
The HM-10 sells well, so it was copied — and then the copy was copied, and then the copy of the copy was faked. All four are sold as "HM-10", often in the same listing, at the same price.
They take different AT commands. Follow a perfectly good tutorial with the wrong one in your hand and the first command you type returns nothing at all. The obvious conclusion is that you broke something. You did not.
Two commands and sixty seconds tell you which one you are holding. That is chapter 2, and almost nothing else covers it at any price.
Inside
Thirteen chapters, and an index you will keep
- 1The four-box modelPhone, module, Arduino, the thing. Find the box, then fix the box.
- 2Which module did you actually buy?HC-05 vs HC-06 vs HM-10 — and the clone family sold under all three names.
- 3Wire it once, correctlyFour wires, the power trap, and the divider rule the internet cannot agree on.
- 4Prove the link before you write codeTwo minutes and a free app, before a single line of your own.
- 5Baud rates and the garbage problemEvery module, every rate — including the number the web gets wrong.
- 6AT command modeFour modules, four dialects, and the setting that makes every command fail.
- 7The upload trapWhy it presents as a broken Arduino, and the two real fixes.
- 8Commands that don't get mangledWhy readString() betrays you, and the pattern that does not.
- 9Driving something realThe L298N, the H-bridge, and the speed control that hid a fault for ten years.
- 10iPhone, Android, the web remoteThe honest browser table, and what it means for what you build.
- 11Building your own controllerThe App Inventor contract, and why a BLE module will never connect to it.
- 12Should you just use an ESP32?Often yes. Here is when it is not.
- 13The troubleshooting matrixEvery symptom, the test that tells you which, and the fix.
Plus three appendices: every AT command per module, a dated parts list with prices, and the sketches.
Inside the pages
Diagrams drawn from the circuit, not sketched
Every figure in this book is code, not a drawing — so every wire endpoint is exact by construction. A generated diagram gets the shape right and the pin number wrong, which is the one mistake a book like this cannot make.
Before you buy
The part most pages leave out
If you have an iPhone and an HC-05 or HC-06, no book can make them talk. iOS does not expose classic Bluetooth serial to apps at all — it is not a setting, an app, or a bug. You need a BLE module, and that is a purchase, not a fix.
And the "drive it from a web page, nothing to install" promise you will read elsewhere is real, but it is a Chrome and Android promise. Web Bluetooth has never shipped in Safari — no version, on any Apple platform — and Firefox does not have it either.
The book says all of this in chapter 10, with the browser table and the date it was checked. It is here too, because finding it out after paying is exactly the experience this book was written against.
The book
62 pages, $9
One payment, yours to keep. A PDF you can put on the desk next to the breadboard, search when something breaks, and open again in six months when you have forgotten which module you bought.
- · Covers HC-05, HC-06, HM-10 and the clones
- · Every number checked against a datasheet, and sourced
- · Every diagram drawn from the real circuit
- · A troubleshooting matrix with the test, not just the fix
- · Dated — prices and browser support say when they were checked
The free sample
The first 12 pages — the front matter, the symptom index, and the two chapters that explain why a good tutorial gave you a bad result. Not a teaser chapter written for the purpose; the actual first pages of the actual book.
Questions
Straight answers
- Which module do I need?
- Chapter 2 is that decision, and it takes one page. The short version: an HC-06 if your remote is an Android phone, an HM-10 if an iPhone is involved, an HC-05 if one Arduino has to call another.
- Will this work with my iPhone?
- Only with a BLE module, and the book says so plainly rather than at the end. Classic modules — HC-05 and HC-06 — are invisible to iOS at the operating-system level. No app fixes it. Chapter 10 covers what does.
- Do I need to solder?
- No. Every connection in the book is a plug-in wire or a screw terminal. You need two resistors, and they push into a breadboard.
- I already bought an HC-05. Is the book still useful?
- Yes — that is most readers. The book covers HC-05, HC-06, HM-10 and the clone family together, because the whole problem is that tutorials assume one and you own another.
- Is this just the free tutorials collected?
- No, and it would not be worth $9 if it were. The free tutorials cover the happy path well. This covers what happens when the happy path does not happen — and the clone family, which almost nothing covers at any price.
- What if it does not help?
- Ask for your money back and keep the book. There is no version of this where arguing over $9 is worth either of our time.
Building with a child rather than debugging your own project? The free car book is the same hardware written for a parent and a twelve-year-old, and assumes none of this one.