A simple silent vibrator for alarms

Home Automation and Security for the Macintosh.

A simple toy becomes a useful pocket annunciator

For the deaf, there is no substitute for a vibrating pocket alarm which can be used to signal all sorts of events from the doorbell to a baby's crying.

For others, it is useful to sometimes have a silent 'pager' which tells only you of some event or alarm. For example if you have to take medicine at a certain time, and you don't want to wake your sleeping partner.

We can subscribe to a 'pager' service, and have YoYo send pages about events while we are not home, but it's pretty slow for announcing events if you're right there.

Here are the two main parts of a simple toy called the SKY Racer. It costs about $15 and mainly is a hand-held transmitter with two buttons, and a little motorized gondola which races around a wire, forward or back, according to the wireless control.

The idea is that we want to end up with the transmitter unit connected to our home automation system so that when we issue a certain X-10 command, a wireless command will be sent to the receiver in our pocket, and the motor vibrations will be felt.

Since there is a lot of plastic stuff that we don't need in our pocket, let's take the motor and the receiver and battery compartment out of the surrounding plastic.

Even with the motor, the receiver and batteries are pretty small.

Note that you may want to affix some blob of epoxy etc. to the end of the motor shaft to make it 'vibrate' more.

Also, you will have to experiment with the antenna, making it less intrusive by folding it or wrapping it inside the ultimate 'package'.

Now that looks like a nasty thing to be putting in your pocket, but you can indeed find a prettier plastic box that will house the whole thing and make it convenient and confortable.

Here's the size of the whole thing in perspective:

You carry around only the parts on the left. The transmitter on the right is going to be hidden in some closet.

The transmitter isn't really much bigger than the 9v battery !

Remove the screws here and flip the circuit board over to reveal the underside...below :

All we need to do is attach two wires. One to each side of the contacts that are shown here.

Then, put the circuit board back down, being careful not to obstruct the normal push buttons with the new wires.

Now bring out the other ends of the two wires, and attach them to the screw contacts of a Universal Module.

The Universal Module has to be plugged into the wall somewhere, and the transmitter needs to be placed so that it's antenna is vertical, and you can get to the unit for maintenance.

Now, all you have to do is send an ON to the Universal Module, anytime that you want to signal an event. Do be sure that either you set the Universal Module to 'momentary' mode, OR that you deliberately send an OFF to it when the alarm has been answered.
Don't forget that you can have two or more 'channels', by purchasing more of the toys, specifically with separate 'frequencies'. Also, you can use as many of the receivers as you want, as all will respond to a single transmitter !

And you might want to have more than one of the hand-held transmitters lying around. It might be a way to signal someone in the house on demand.

Problems you're going to have

The antennas must be reasonably placed in order to get good signals over most of your house. Some places may not be good for reception. Know them.

The receiver will sometimes 'jerk' due to radio signals from airplanes, or even from your wireless telephone. But you should be able to decide that those were false because they never cause the vibrator to come on continuously.

The batteries will need to be replaced according to use, but I've found that they seem to last several months in this application.

Last modified: August 28, 2007
Michael Ferguson, webmaster@shed.com