Create a call button for a family member in need


The If This Then That (IFTTT) app recently became just IF, because the IFTTT team recently diversified with a new two-letter app, Do [4]. Both apps use recipes that wait for an input and, once received, continue to a predefined action. Do recipes wait for a tap on your smart device, then carry out the action. In this case, I use an IF recipe that waits for a signal from the Cloud module then sends an SMS text (all screenshots were made when IF was IFTTT).

To use an IFTTT app, you need to download it from your app store and set up an account. From your account page, you can then download and activate channels (Figure 4) and set up recipes. The channels you'll need for this project are littleBits [5] and SMS [6].

Figure 4: Channels allow you to interact with devices and Internet services. Browse hundreds of channels (left) by choosing Channels from your IF(TTT) Settings screen (right). A color icon indicates you have activated that channel.

Now you're ready to create a recipe (Figure 5). Choose the first "This" plus icon and find the littleBits channel; it will ask you to choose a cloudBit. Next, choose the "That" plus icon and find the SMS channel. You'll need to fill in the cell number to which the text message should be sent. Once you have saved the recipe, click it and choose Edit. By deleting the default message, you can input your customized text. Clicking Check Now reviews your choices to make sure they're compatible. Before proceeding, be sure to enable the recipe and turn on the Receive notifications when this Recipe runs.

Figure 5: IF(TTT) walks you through creating a recipe. A log (far right) keeps track of your actions.

Building the cloud call button is simply a matter of attaching the Power, Button, and Cloud modules together and plugging in the unit (Figure 6). Now, when the button is pushed, the lucky caretaker gets a message to assist (Figure 7). The text message did not always arrive immediately after the button was pushed, but I rarely had to wait more than 30 seconds before the message arrived.

Figure 6: The simple cloud call button.
Figure 7: The recipient receives a message for help.

The cloud call button is an elegant solution; however, because it's tethered to a wall outlet, it becomes unwieldy when the patient starts moving around a bit or is in a wheelchair, for example. With a little expertise, you could probably build a suitable battery from an old iPod or cell phone to break the bond with the mains, but another solution is to return to the wireless modules and create a call box reminiscent of earlier days.

Retro Call Box

Certainly you've seen a period movie in which the servants are called to action by a rank of bells [7], each of which is assigned to a room in the house. My original idea was to place a button in each room with a wireless transmitter that would send a signal to a conveniently located receiver, much as each room in a manor house would have a bell pull or button that converged on one annunciator box. Unfortunately, the wireless units do not pair up that way. According to the literature that comes with the transmitter and receiver, "Multiple wireless receivers can be used with a single wireless transmitter, but only one wireless transmitter can be used in proximity to another wireless transmitter" [8]. My resulting design, therefore, was a little uglier and more unwieldy than I had originally planned. Also, I had to make do with the modules on hand, so the end result was not ideal.

Figure 8 shows the modules needed for the multiroom call buttons. The three Latch modules in the center convert the input devices to on/off switches. That is, you actuate the input module once to turn it on, then you have to actuate it a second time to turn it off. This guarantees that the caretaker does not miss the call for help when momentarily stepping out of the room. The switch can then be turned off when the call is answered.

Figure 8: Multiroom call button modules (left) and the assembled unit (right). The blue devices are power. The orange modules include the wireless transmitter (top), three latches and two wires (middle), and a three-way fork (bottom). The pink input units include a slider, a button, and a pressure sensor.

If I had owned three buttons, I could have eliminated the Wire modules and created a neater component. However, this just shows that you have many ways to send signals in your designs.

The call box (Figure 9) uses two servomotors and a bright LED. A Pulse module (pink) between the wireless receiver and the LED makes the light blink to make it more noticeable. You can even adjust the speed in which it blinks. The servomotors were set to Swing instead of Turn mode, so they continuously move up and down to ring the attached bells.

Figure 9: Oh dear! The master requires help in the solarium.

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