Facts :
Vibrations calm babies down.
Some baby wares are built with a vibrator.
Vibrations made by playstation controlers are very similar to the ones they build their baby wares.
My baby's cradle isnt built with a vibration engine.

Observations :
My cradle has a foldable wooden structure.
the matrass hangs from wooden beveled rectangle, hold by a fabric.
A playstation controler has about the same curvature then straightness than the wood that holds the matrass.
A playstation controler is ugly.
A playstation controler operates a bit under 5v.
My old phone operates a bit under 5v too.

Solution :
Build a device that would vibrate and would be strapable on a cradle to calm the baby before he cries.

Addendum 1 : would need its own power source. usb cord is ugly and short. Needs more mobility.
Addendum 2 : would not be standard AA batteries because i dont want to open the whole assembly each time it's empty.

Updated solution :
Tweek the device so that it operates on a rechargeable battery.

Step 1: Disclaimer and Tools Needed

First off, I want to underline the fact that I am in no way responsible for ANYTHING you do.
Be cautious with you own life, but be MORE cautious with the lifes of others, especialy innocent little children.

The power in this thing is 3.7volt, but has an AC charger connected to it. If for some reasons something goes wrong with the 220v charger, well, you fried your newborn child. I mean : litteraly.
Dont ever charge it when strapped to the cradle. Nevar Evar.

Now that we are clear about that, you'll need :

- An inexpensive chinese copy of a playstation controler. (got one for equivalent of 3 usd)
- An old cell phone with its charger. (i used a 12 years old nokia 3310)
- Wires, soldering stain, hot glue stick, some tape, a switch.
- Pliers, soldering iron, glue gun, screw driver.

Step 2: Open and Watch

Open your playstation controler and take out the electronics, leaving only the 2 vibration motors.

Take appart your old phone, only keeping the battery, battery connector and the AC plug connector. On my nokia 3310 it was extremely straight forwards.

Note where the correct wires need to go. + needs to go on + and - on -.
The polarity or the battery should be indicated.
The inside part of the charger plug is +, the exterior is -. Find out which pin is which.

Step 3: Soldering

Connect the + ac plug connector pin to the + battery conenctor pin, and the - to the -.
Check it again. and check your battery too. Once you are really sure, solder them.
DON'T SOLDER DIRECTLY ON THE BATTERY.

Solder your motors + wires to a switch, then to the + battery connector.

Solder the - wires directly to the - battery connector.

As i suck with soldering things, i decided to seal them into hot glue. It makes them stronger.

Check again the polarity of the battery and the wires, then tape the battery to its connector so it wont move.

Step 4:

Observe your space and determine how to fit the battery, the switch and the AC connector inside the controler. You may have to break or cut some screw holes. My AC plug was a bit too big. I had to trim a bit of useless plastic.
I put the switch and AC plug in the L1 and R1 index finger buttons, and the battery assembly inside the body. It fits pretty good.
If your wares dont fit good inside the controler, it will stay half open and make some useless noise, but it'll still do the job.

Glue the switch and AC plug whereever you want them to be. Don't go easy on the glue, it has to be sturdy.

Cap the controler buttons holes. You can use whatever. My cat played with the buttons, so i used tape and cardbox.

Screw the controler back together.
I broke too much plastic screw columns (or whatever these are called) to be able to screw it, so i just taped it close.

Step 5: Word of End

Strap the assembly on your crying baby cradle.

Turn it on when he shows the signs of imminent cry.

Watch the magic.

AGAIN THE DISCLAIMER :

I am in no way responsible for anything that may happen to you or your kids. Only YOU are.

For safety reason, don't leave the charger pluged when strapped to the cradle. Remove it, charge it, strap it again. You may use tape or velcro or whatever.

If in any way you feel inconfortable with the device, don't use it and throw it away.