The Talking Scale

Now before you attempt this project make sure your spouse:

1. Is not fat.

2. Has a good sense of humor.

3. Is not trained in karate.

4. What spouse? I spend all my time in the attic running wires.

We will learn how to modify a common bathroom scale so when someone stands on it HAL 2000 will play a wave file through the house.

One of the many actions supported by HAL 2000 is the ability to play a windows wave file. I have set up many doors in the house to play wave files when they are opened or closed. Once you set up your whole house audio you will have loads of fun firing off the best wave files the web has to offer.

For this project you will need 2 items. First, you will need to get an electronic bathroom scale. I have a very popular scale made by Health-O-meter model number 842 which can sometimes be found at K-mart.  Next you will need a wireless key chain remote and X-10 receiver easily picked up at radio shack (Part Number 61-2663).

I did not want to hardwire the scale, as the wire would surely give away the fun. In addition, it is convenient to be able to place the scale in the guest bathroom when you have company. (Close friends I hope.)

I first took the R.F. key chain remote apart. Remove the circuit board completely from the plastics. Don’t worry about the house-code selector as I found when it is completely removed from the circuit board the R.F. remote operates on house code M. (If you must use a house code other than M, you will need to painstakingly connect the brushes from the house code selector to the circuit board in the position required to get your desired house code.) Trust me, just chuck it over your shoulder and use house code M. Be sure to set your RF Receiver to also use house code M.

 Opening the scale requires only grabbing the top and bottom sections and pulling apart. There are two simple switches that are used to detect when someone is stepping on the scale. Luckily both switches are not required by the scale but are put in for redundancy. I found the scale operates just fine with only one. The weight sensors are simple contact closure mechanisms triggered by your body weight and integrated into the two lower resting pads. I simply cut the two wires (black and red) on the left hand switch very close to the LCD display (Giving me an adequate length of wire to work with.)

The R.F. remote has four momentary snap buttons, one that sends the on command and another that sends the off command for unit numbers 1 and 2. Carefully remove the "snap button" by peeling it from the circuit board. You will need to solder the two wires from the scales weight sensor to the circuit board as illustrated in the photo below. (These are the red and black wires on the left hand side of the photo.)

Next you will need to get 2 pieces of wire that are about 3 inches long. These will be used to connect the scales 9-volt battery directly to the RF remote. I know what your thinking; the scale uses a 9-volt battery and the RF remote only requires 3 volts. Well let’s just pretend we’re Tim Allen from Home Improvement and we are going to soup this bitch up! I found that the RF Remote worked just fine at 9-volts. Be sure to observe proper polarity and connect the RED wire to the (+) side of the 9-volt battery and the black wire to the (–) side of the battery. Solder the wires to the circuit board as illustrated on the picture above. (These are the red and black wires on the right hand side of the photo.)

Carefully place the circuit board just above the 9-volt battery well and snap the scale back together. (I removed one of the plastic reinforcement ridges on the bottom part of the scale so the circuit board would fit easily into place.)

Put the 9-volt battery in and test the scale.

One problem I found with the key chain remote is that the X-10 "ON" command is continuously sent when someone is standing on the scale. If not handled properly in your automation software, you will be firing the wave file 15 to 20 times each time someone steps on the scale. Here is what you do: In HAL 2000 you can easily handle this by setting up sensors, timers and flags to operate with your rules.

In HAL 2000 Create:

1. A X-10 Sensor named SCALE that is set to House Code M Unit 2

2. A timer named SCALE

3. A flag named ON SCALE set default false.

4. A Rule names SCALE TIMER that triggers on the expired SCALE timer.

a. And sets the ON SCALE flag to false.

5. A Rule named SCALE that fires with a trigger event of the SCALE sensor ON

a. And has a secondary condition that requires the "ON SCALE" flag to be false.

b. Add an action to make the ON SCALE flag true.

c. An action to plays the wave file or text to speech of your choice.

d. An action to sets the SCALE timer to countdown 15 seconds.

 

If implemented correctly, the wave file should only fire once since the ON SCALE flag gets set to TRUE upon the first event and must be FALSE for the rule to fire. Be sure to create the additional rule that will reset the flag to FALSE once the 15-second timer has expired.

Here are a few of the wave files I have used for my bathroom scale.

I'm Not fat I'm big boned!

Follow Your dreams. I'm living proof. Beefcake. Beefcake!

Cartman, your such a fat ...

Does this suit make me look fat..

I'm not fat I'm festively plump!

You're going to be fat forever...

I'm thankful for stuffing and pie...