Learn Hardcore French: Ce bracelet connecté lui envoie des notifications quand elle bouge trop peu. - This smart bracelet sends her notifications when she moves too little.

bracelet is masculine and starts with a consonant sound /b/, so you use ce:
- ce bracelet = this/that bracelet
cet is used before a masculine noun that starts with a vowel or mute h:
- cet ordinateur, cet homme
ceci is a pronoun (“this (thing)”), not an adjective; you do not put it before a noun:
- ceci = this (on its own)
- but ce bracelet = this bracelet

So ce bracelet is the only correct form here.

What exactly does connecté mean here, and why is it placed after bracelet?

Here connecté is an adjective meaning “connected / smart / internet-connected” (like smartwatch or connected bracelet).

It agrees in gender and number with bracelet:
- un bracelet connecté (masc. sing.)
- des bracelets connectés (masc. pl.)
- une montre connectée (fem. sing.)

Word order:

Many short, very common adjectives come before the noun (e.g. un petit bracelet, un beau bracelet).
Many more descriptive or technical adjectives, especially ones formed from verbs or past participles like connecté, usually go after the noun.

So un bracelet connecté is the natural order. Un connecté bracelet is wrong.

Who does lui refer to, and why is it lui instead of elle or à elle?

In this sentence:

lui is an indirect object pronoun meaning “to her / to him”.
It replaces à elle or à lui, and it is used for both masculine and feminine people in the indirect object role.

Structure:

envoyer quelque chose à quelqu’un = to send something to someone
envoyer des notifications à elle → lui envoyer des notifications

So:

Ce bracelet connecté lui envoie des notifications…
- literally: “This connected bracelet sends to-her notifications…”

You cannot use elle here because elle is a subject pronoun (“she”), not an indirect object pronoun.
You could say à elle for emphasis (Ce bracelet envoie des notifications à elle), but it’s heavier and less natural than simply lui.

Why is the verb envoie spelled like that? Why not envoies or envoient?

Envoie is the 3rd person singular present tense of envoyer:

j’envoie
tu envoies
il / elle / on envoie
nous envoyons
vous envoyez
ils / elles envoient

Here the subject is Ce bracelet connecté = il (he/it), so the correct form is:

(il) envoie → envoie

Envoies is only for tu.
Envoient is only for ils / elles (they).

So Ce bracelet connecté envoie… is correct.

Why is it des notifications and not les notifications or de notifications?

Des here is the indefinite plural article = “some” notifications.

des notifications → some notifications (an unspecified number)
les notifications → the notifications (specific ones, already known)
de notifications → would be used only in certain structures (e.g. pas de notifications, beaucoup de notifications).

In this sentence, we’re talking generally: the bracelet sends some notifications whenever the condition is met, not specific pre-identified notifications.
So des notifications is the natural choice.

Why is it quand elle bouge trop peu and not just elle bouge trop peu or something else?

Quand means “when(ever)” here and introduces the condition under which the bracelet sends notifications.

Structure:

Ce bracelet connecté lui envoie des notifications
= This connected bracelet sends her notifications
quand elle bouge trop peu
= when(ever) she moves too little

Together:

Ce bracelet connecté lui envoie des notifications quand elle bouge trop peu.

You could also say lorsqu’elle bouge trop peu (more formal / written), but quand is neutral and very common in speech.

If you removed quand, the second part would just be another independent statement, not clearly linked as the condition.

What does trop peu mean exactly, and how is it different from pas assez?

Both trop peu and pas assez can mean “not enough”, but:

trop peu literally: “too little”
pas assez literally: “not enough”

Nuance:

trop peu often emphasizes the quantity being too small, sometimes with a slightly more evaluative or “measured” feeling.
pas assez is the most common, neutral way to say “not enough”.

So:

Elle bouge trop peu. = She moves too little.
Elle ne bouge pas assez. = She doesn’t move enough.

In most everyday contexts, they’re interchangeable, and both would be understood the same way in this sentence.

Why is the subject of bouge elle and not lui? Could lui be the subject?

No. In standard French:

elle is a subject pronoun = “she”.
lui in this sentence is an indirect object pronoun = “to her”.

So:

elle bouge = she moves
lui envoie = (it) sends to her

Roles in the sentence:

Subject of envoie: Ce bracelet connecté (it)
Indirect object of envoie: lui (to her)
Subject of bouge: elle (she)

If you said lui bouge, native speakers would read it as “he moves” (since lui can sometimes be used as a stressed subject — but that’s another structure and not what’s happening here).

Here the clean, standard subject form must be elle for “she”.

Is bouger always used like this, or do I sometimes need se bouger?

Bouger has two common uses:

Intransitive, no reflexive pronoun: to move (change position, be in motion)
- Elle bouge trop peu. = She moves too little.
- Ne bouge pas ! = Don’t move!
Transitive: to move something (cause it to move)
- Bouge la chaise. = Move the chair.
- Je ne peux pas bouger le bras. = I can’t move my arm.

Se bouger (reflexive) exists but is more colloquial and often means:

“to get moving / to get off your butt / to make an effort”
- Allez, bouge-toi ! = Come on, get moving!

In your sentence, we’re just talking about her physical activity level in general, so the simple bouger with elle as subject is correct: elle bouge trop peu.

Could I replace trop peu with something like pas beaucoup? Would the meaning change?

You could say:

Ce bracelet connecté lui envoie des notifications quand elle ne bouge pas beaucoup.

This still means she doesn’t move much; the overall idea is similar. Nuances:

trop peu / pas assez → more directly “not enough” relative to some expectation or standard.
ne … pas beaucoup → “not a lot / not very much”, slightly more descriptive and less explicitly about a standard.

For a fitness-tracker context, trop peu or pas assez feels a bit more “measured,” like it’s comparing her movement to a target. But all three are understandable and natural.

Is bracelet connecté the usual way to say something like “fitness band” or “smart band” in French?

Yes, bracelet connecté is very common in modern French for devices like fitness bands/smartbands.

Other possibilities you might see:

bracelet d’activité or bracelet d’activité connectée
tracker d’activité (uses English tracker)
bracelet intelligent (less common, sounds a bit marketing-ish)

But in everyday language, bracelet connecté or bracelet d’activité are the usual expressions.