Counter Revolution: The Audible Counter

Figure 1. The Audible Counter

Designers: Ken Bradley and Sirin Yaemsiri
Client Coordinator: Judy Stroupe, Orange Enterprises, Inc.


The audible counter was developed to provide audio and visual counting for people with physical and/or cognitive impairments who work at a supported employment center. There was a need for a counter, which would help a person keep track of the work they had accomplished. With audio feedback, this device is particularly valuable for people who are unable to read a numeric display, or for people with autism who benefit from audio stimulation.

Figure 1. The Audible Counter

Figure 1. The Audible Counter

To use this device, the employee presses a large button on the front of the counter every time they complete a task, such as stuffing an envelope. The device responds by incrementing the count shown on the LCD display, and announcing the count with an audio message. Additional audio messages provide encouragement every 5 counts, as well as prompts when the device is idle for a period of time. For those employees needing a custom increment switch, their supervisor can plug in a commercial switch into a standard 1/8 inch jack on the unit. Additional buttons on the unit are used to reset the count to zero or place the device in “sleep” mode.


According to Judy Stroupe, client coordinator, “the counter will increase the employee’s earning power and also increase their independence in their work by relying less on a supervisor to keep up with their count.” Thus, when an employee finishes a task, he/she can press a button on the audible counter and the device will output the current count both visibly and audibly. The counter is designed to be simple to use, and will save the current count until the user presses a reset button. The counter will be applied to various tasks by the employer.


The custom circuit is designed on a pre-printed circuit board that minimizes noise during recording and playback. It also makes the circuit more robust and less prone to wires breaking. The device is controlled by the PIC microcontroller (Microchip, Chandler AZ), which receives input from the increment switch and provides the current count visually on the LCD screen and audibly through a speaker. Custom digital recordings are stored in the ISD record/playback chip (Winbond, San Jose CA).

The program works using timer and input interrupts from the microcontroller itself. At start, the program initializes all variables and then enters an infinite while loop. The loop can be interrupted by the PIC timer, which increments the idle time, or by user inputs, which include the “sleep”, “reset”, and “increment count” buttons. Every time the count is modified, either by reset or increment, the count number is stored in flash memory on the PIC to prevent data loss via power failure. Upon power up, the count is loaded from the flash memory. The microprocessor PIC and ISD voice record/playback chip can go into a sleep mode where they draw microamps of current. The other components, such as the inverter, speaker, and amplifier, run off a 5V supply. The PIC turns the 5V regulator on and off, which saves battery life when the device is not in use.

For the count numbers “one” through “ninety-nine”, professionally recorded audio files were obtained from BeVocal Café ( There are three custom recorded audio encouragement messages, including “excellent work,” “good job,” and “you’re doing great.” These messages play every five counts. There are three custom-recorded audio prompts, including “do another,” “keep going,” and “get back to work.” These messages are played every 30, 60 and 120 seconds without user input. There are also custom recorded messages for “hello” and “goodbye” when the supervisor presses the awake/sleep button.

The enclosure is a 9.92” x 4.76” x 2.75” project box with a cutout for the LCD display (EAI Enclosures International, Libertyville IL). The box has a battery compartment for four AA batteries. The LCD count display, increment button, and speaker are mounted on the top panel of the enclosure. The LCD cutout is wide enough to fit the 20 characters by 4 line display. The increment button, the only button that the employee will have access to, is a green pushbutton switch. It has a 1-3/8” activation surface and activates no matter where it is pressed for easy access by employees who have limited motor control. The speaker is mounted on the inside of the enclosure and covered by a wire mesh. The supervisor controls, the reset button, awake/sleep button, volume control, and alternate switch jack are mounted along the side of the enclosure. The reset and awake/sleep buttons are flush against the surface of the enclosure to prevent accidental pressing. An on/off switch to the battery is also mounted to the top of the enclosure.

The total cost of this project was $261.

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