High-Power Two-Stage Rocket

I've made a two-stage rocket before, but that used two motors touching, with the first motor igniting the second motor. That only works for smaller rockets, so I wanted to try a different method for larger high-power rockets. The premise is simple: I wanted to have some electronics in the upper stage that would ignite the upper stage motor at the right time, which would separate the two stages. The first stage would then deploy a parachute, while the second stage flew on. Here's how I did it:

• In the upper stage, I made a compartment for the electronics, which would be an altimeter and a battery. This compartment only takes up half of the space within the tube, as the other half is for the motor's ejection charge to deploy the parachute. 

• From the electronics bay, a straw goes down all the way to the upper-stage  motor. An igniter goes down this straw, with the other end attached to the altimeter. After a predetermined time after launch, the altimeter will ignite the motor.

• Just in case the motor is not able to deploy the parachute, the altimeter will set of an ejection charge at the peak of the rocket's flight, which will eject the parachute if the motor had not been able to do that.

• The first stage's parachute will be deployed via the ejection charge of the first stage-motor. This will happen after the two stages separate.

Here is the electronics bay:

On the left is the straw that goes down to the motor, and on the right you can see the other side where the backup ejection charge for the parachute will go.

This is what the flight of the rocket will look like: