WowWee Rovio "Master" ModPosted by Thel on Monday, 16 November 2009
For today, I’ve gone out and taken steps to give our future robot masters one more way to assert control swiftly and painlessly :) In this case, my Rovio can turn anything on or off that plugs into the wall. I'm using a lamp right now for fun, but I think when I go out of town I might add some speakers as well!
The general idea of the mod is that I've set it up so that when I turn on Rovio's built in head lamp using the web controls, an electrical control box with say, a lamp in my home, plugged in is turned on or off. After it comes on I turn the lamp off or it will drain the transmitter. Then, when I turn the LED on again the lamp gets turned off at the wall.
- A Key chain type wireless controller
- A Low voltage Relay, I used a 5 V DC relay
- Some soldering tools, wire and associated material
- A PNP Transistor
- A Screwdriver and pair of Wire Cutters
Note: You must disconnect Rovio's Battery before starting!
You will need to open your Rovio up; there are 6 screws around the bottom side. Once inside, locate the headlight mounting bracket on the front to the bottom half of the case. It comes off by removing 2 screws. Once it is off, separate the the mount and the board by removing a further 2 screws.
Now, locate and disconnect the white wire leading to the LED. Be careful to leave all of the colored wires as they are. Once the wire is free, reassemble and mount the headlamp assembly, as this is part of the auto pilot function of the Rovio. Finally, connect the white wire to your transistors base pin and set aside.
You will now need to tap off of the battery to run the relay. (A relay is a way for one electrical thing to control a different electrical thing and keep their power, or in this case, batteries, separated.) You may choose a different method, but here is mine:
I followed the large red and black wire from the battery to the power board on the right side of the case. Then, I removed the 2 screws at the top of the board and pulled it up to examine it. What I found was that there are three pads with penetrations on the board. The pad in the lower left hand corner of the pad was connected to the red or positive line. And the pad directly to the right of the black or negative line was tied to the black line.
I soldered 2 wires, one to each pad and tagged them as two with polarity they where. I then remounted the board leaving the wires hanging out.
Next, you will be attaching the relay to the transistor and the battery. To do this, solder the red battery wire you made to the transistor on the "Collector" pin. Solder a piece of wire between the transistor's "Emitter" pin and one of the relay's two coil pins. I used about 6 inches. Finally, solder your black power wire to the other relay coil pin.
The last part electrically is wiring the relay to the remote. This is pretty straightforward so you can do it how ever you like. The gist is that you pull the guts out of the remote and remove the button from the remote's board. Then, you solder 2 wires into the two spots the button went to and solder those 2 wires to the common and normally open pins on the relay.
If you are working with a relay with 4 pins instead of 5, just use the two pins that aren’t coil or control pins.
That’s it! Now all you have to do involves the parts in the case. I trimmed the remote's housing and zip tied it to the power board, as well as finding found spaces for the other components where I could. Just make sure to heat shrink all your wire and make sure that the remote board doesn't touch any other boards. You may need to put insulation around the remote's board.
Step 4: Revision
I realized that there’s some backing up of power. Mostly in my head, but to be safe, I've made a small change to the above instructions. I've run a wire back to the headlight with a resistor.
To do this, you will need to do 3 things:
- Attach a wire to the vacated space on the LED board
- Solder a small resistor 1 to 5 ohms to the end of the wire and heat shrink the solder and exposed wire.
- Solder the other end in line with the white wire making a Y. So you should have the Base pin, the white wire that originally went to the LED and the remaining side of the resistor all joined.
You may need to use small sections of wire, just use your best judgment on the how. I can't be sure but I think I was getting a drop out in the camera so this revision will dump any voltage leakage when the LED is off.
These parts can be ordered from Radio Shack
-Relay (5VDC/1A SPDT Micro Relay, Model: 275-240 | Catalog #: 275-240)
-Transistor (PNP Amplifying Transistors (15-Pack) Model: 2N3906 | Catalog #: 276-1604)
This part can be found on amazon.com
Wireless Remote Control
An improved schematic
The Remote and Receiver
The Remote Opened Up Before Modification
The remote with its buttons removed by heating the solder and pulling. Seen now with the wires that will lead to the relay.
The Remote and the Relay
The headlight board on the front of Rovio with the white wire cut free. The white wire seen in front will go to the trasistor and resistor; I made the wire come together in a Y and heatshrinked pretty much everything.
The Power board: note the 2 clusters of holes in the lower left.
Everything is back in place and zip tied down. You can see the body of the remote at the top of the picture or on the right side of Rovio strapped to the power board. Its cut up to fit while still leaving plastic between the remote and the power board. Always have too much wire so you can fit components where they don't get into moving parts or anything else!