Probamos la máquina de coser con el pedal de control.

Because for -ar verbs, the nosotros form is the same in the present tense and the preterite.

• probar = to try / to test
• probamos can mean:
  • we try / we test (present)
  • we tried / we tested (preterite)

So you need context to know which one is intended.

Examples:

• Hoy probamos la máquina. = Today we’re testing the machine.
• Ayer probamos la máquina. = Yesterday we tested the machine.

Spanish often leaves out subject pronouns because the verb ending already shows who the subject is.

• Probamos already tells you the subject is we
• So nosotros probamos is possible, but usually unnecessary

You might include nosotros only for:

• emphasis
• contrast
• avoiding confusion

Example:

• Nosotros probamos la máquina, pero ellos no. = We tested the machine, but they didn’t.

La máquina de coser literally means the machine for sewing, which is how Spanish says the sewing machine.

The structure is:

• máquina = machine
• de coser = for sewing / to sew

Spanish often uses noun + de + infinitive to express the purpose of something.

Similar examples:

• máquina de escribir = typewriter
• gafas de sol = sunglasses
• cepillo de dientes = toothbrush

So máquina de coser is the natural Spanish expression for sewing machine.

Spanish uses definite articles (el, la, los, las) more often than English does.

So where English might say:

• We tested a sewing machine
• We tested the sewing machine

Spanish often naturally uses:

• Probamos la máquina de coser

Whether it means the or is just referring to the known item depends on context. In many situations, Spanish prefers the article where English might omit it.

Here, probar means to test or to try out.

This verb can have several meanings depending on context:

• try/test a machine, a method, a product
• try on clothes
• taste food

In this sentence, because the object is la máquina de coser, the meaning is clearly tested or tried out, not tasted or tried on.

Here con means with in the sense of using something.

So:

• Probamos la máquina de coser con el pedal de control = We tested the sewing machine using the control pedal

This phrase tells you the means or instrument used to do the testing.

Con is very common for this idea:

• Escribo con un bolígrafo. = I write with a pen.
• Abrí la puerta con la llave. = I opened the door with the key.

Most naturally, it describes how the machine was tested: using the control pedal.

So the usual interpretation is:

• We tested the sewing machine with the control pedal

In theory, Spanish can sometimes allow ambiguity, just like English:

• Did we use the pedal to test it?
• Or are we identifying the machine as the one that has a control pedal?

But in normal usage, this sentence will usually be understood as we tested it by using the pedal.

Because pedal is a masculine noun in Spanish:

• el pedal

There is no special rule here that an English speaker can easily guess from the ending, since nouns ending in consonants can be masculine or feminine. You usually need to learn the noun together with its article:

• el pedal
• la máquina

That is one of the best habits in Spanish: learn nouns with el or la, not in isolation.

De control means something like for control or control-related.

So:

• pedal de control = control pedal

Spanish often uses de where English uses an adjective or a noun placed before another noun.

Compare:

• pedal de control = control pedal
• centro de salud = health centre
• tarjeta de crédito = credit card

So this is a very common Spanish structure.

Because in Spanish, only two preposition + article combinations contract:

• a + el = al
• de + el = del

But:

• con + el stays con el
• para + el stays para el
• por + el stays por el

So con el pedal is correct exactly as it is.

Yes. That would also be correct.

• con el pedal de control = with / using the control pedal
• usando el pedal de control = using the control pedal

The version with con is shorter and very natural.
The version with usando is a bit more explicit about the action of using it.

Because probamos is ambiguous on its own, Spanish often adds context words.

To make it clearly present:

• Ahora probamos la máquina de coser con el pedal de control.
• Estamos probando la máquina de coser con el pedal de control.

To make it clearly past:

• Ayer probamos la máquina de coser con el pedal de control.
• Probamos la máquina de coser con el pedal de control esta mañana.

Using estamos probando is especially clear for right now / currently testing.

Yes. Máquina de coser is the standard and natural term in Spain, and more generally across the Spanish-speaking world.

A native speaker would immediately understand it as sewing machine. It is the usual everyday expression, not a strange literal translation.