Motorized gadget: step #5

       So I got to the part of fixing iPhone to the motorized vent.

      This was quite a challenge because the phone has to be placed in perfect center or otherwise the system won't be able to rotate. Secondly to fixate screws and nuts, you have to be jeweller (that's why I used rivets instead).

So first I attached some aluminum ribs so I would be able to attach iPhone cover to the moving part.

        Next I drilled holes in the iPhone cover, that would match the holes on the aluminum ribs beneath. 

After riveting iPhone cover to the aluminum ribs, I had to ensure that vent system can rotate 180 degrees. It couldn't... That's why there are several unnecessary holes in the iPhone cover. :)

        So this works for now as you can see in the video below:

 Unfortunately there are additional problems that I have to solve. 

1. How to connect iPhone wires so that they would allow to move the center part.

2. How to disguise the vent so that it when iPhone can be seen, no other stuff is visible (like the center axis).

Motorized gadget: step #3

OK, so I got trough the previous problems.

       First of all I applied heat sink to the transistor to cool it down. It's much better now, but still the heat sink is a bit warmer than it should be. Maybe some little fan will be attached. Since the heat sink doesn't get hot all the time I will proceed observing this process. For transistor cooling I used old heat sink from CPU and also applied special paste that would better distribute heat between transistor and heat sink. 

    About the second problem (described in last blog post) - I borrowed oscilloscope to see what is happening with the pulse signal that should control the servo.

    To see how the circuit works at first I didn't add the control current - power supply that produces current from 0-10V.

These are the results:

1. Potentiometer in the center position (on NE555 timer pin #5 current is 1.6V):

As you can see pulse signal is normal, nothing unusual.

Motorized gadget: step #2

      It's time for the next step. As I mentioned before, I want to create scheme/mechanism that would be able to control servo based on the current in car stereo remote wire (intended to switch on/off audio amplifier). 

To understand it better - when I switch on car stereo it gives current on the remote wire, which "says" to the amplifier: "Switch ON!". Scheme "sees" the current in remote wire and starts turning servo to the other end (180 degrees) that flips a panel in center console of the car. When car stereo is switched off, current in remote wire is gone and scheme turns servo the other way around (180 degrees back). 

To do this I encountered two main problems:

   1. Scheme and servo had to receive 5 V all the time.

   2. To control servo it has to receive pulse signal through control wire.

    

     The first problem solving is described in my recent blog post. I created scheme that can reduce voltage from 12 V (which is commonly found in car) to 5 V. The voltage can be adjusted with potentiometer. Scheme works well although, transistor gets very hot. Heat sink will be applied soon to cool it down.

      Information how to solve my second problem I found in the internet. But before that I'll try to explain about the basics of servo performance. Servo has three wires - plus, ground and control. To the plus wire 5V current has to be applied from the scheme that I created in the previous blog post. The fun starts with the control wire. To move servo, pulse signal has to be transmitted. If the pulse signal is 1 ms (approx. 80Hz) the servo will turn fully left, if the signal is 2 ms (approx. 80 Hz) the servo will turn fully right.