The Jenda by Finger-String

Jenda by Finger-String is a talking calendar that keeps daily reminders. It is the verbal version of the family activity calendar stuck to the front of the kitchen refrigerator. The inventors came to Nevis Group looking to move from concept to reality. The initial prototype was made out of an existing game that had enough buttons on it to do all the functions needed for the concept. The game was wired to a PC to allow very fast movement from an ethereal concept to a working prototype to test out the idea. While not pretty, it served the purpose of allowing the Finger-String group to refine the functions and general concepts of the Jenda.

Jenda circuit board

Once the general working concept was defined, work on a representative prototype began. Using parts that were off the shelf, we were able to build a prototype that was self contained and demonstrated the overall concept. This prototype also allowed for modifications on the fly. As more experience was gained using the Jenda, there were still small details in it's design and function that needed to be worked out.

Next, Nevis Group started to design the electronics and software for the Jenda. Because we had made a representative prototype, the design of the electronics and software was really a matter of capturing the prototype. A few key technical points were identified one of which was the battery usage. The unit will be running on batteries, so it must be very low power. We were able to reduce the power consumption during standby periods to less than the normal self discharge rate of typical batteries. This meant that the batteries would last as long in the Jenda as they would in the kitchen drawer.


After woking out the last bits of the design and function details, the process of creating the final unit began. The general outline and design of the Jenda was given to a design house to create the overall look. With the artist concepts in hand, we began working with mold designers in Indonesia to create the molds. At the same time, we began working with an assembly house, also in Indonesia, to assemble and package the Jendas.

Ease of use was also key. While there is a "computer" inside the unit, it must not feel like a computer. This meant no delays when a button is pressed. The Jenda had to go from a standby / low power state back to full speed and talking fast enough that there was no noticeable delay. The power standby circuits and software are able to bring the Jenda to life in less than 10 msec. Once alive the Jenda needs to be responsive. No delays while it is "off thinking about something". We designed a cooperative mulitasking operating system to handle this. We also needed to save a lot of data. Each message recorded is a separate file. In order to keep everything moving along quickly, a custom file system was developed. This file system runs in a NAND flash device so no messages are lost when the batteries are changed.


As part of the ease of use, the Jenda was programmed to work in 3 different languages: English, Spanish and French. Nevis Group worked with Finger-String to have all of the voice prompts professionally recorded. Once recorded, the prompts were compressed and loaded into the Jenda.

After a trip to Singapore and Indonesia to check audit the molding and assembly facilities and to do first article inspections, the first 2500 Jendas were ordered.

Nevis Group continues to provide Finger-String with technical support and will be working together on future projects.