keypad

Description: The transceiver Yaesu FT2000, along with the FT950 and FT450 models, features two key functionalities: a CW memory keyer and a phone voice keyer. These keyers are activated via small buttons located in the lower left corner of the panel. Frequent usage of these buttons may reveal their small size and difficult accessibility, particularly due to obstruction from the microphone connector, leading to an ergonomic disadvantage. Acknowledging this issue, Yaesu provides an optional keyboard, the FH-2, which includes 12 buttons that are believed to be the most utilized by operators. However, some users may find that only a handful of buttons, such as five for recalling stored messages, are frequently needed, while the remaining buttons are seldom used, making the panel buttons a viable alternative. As a result, a custom keyboard design has been inspired by an article in a Czech HAM magazine (by OK1UKV). The construction is straightforward, consisting of switches and resistors housed within a box. The transceiver detects the resistance between the signal wire and ground, with different resistance values corresponding to different buttons. A circuit diagram provides a list of resistance values linked to each button, including those that are infrequently utilized. The criticality of resistance values has not been thoroughly tested; however, the use of two resistors in series with a difference of less than 10 ohms is sufficient, and less precise resistance values may also be applicable. Finding two resistors that meet the desired specification is often easier than sourcing a single resistor with an exact value. The push switches utilized are from older PC keyboards, predating the less reliable rubber switches, although suitable replacements should be readily available.

The custom keyboard design for the Yaesu FT2000 transceiver is a practical solution for enhancing user experience by addressing the limitations of the factory-installed buttons. The schematic involves a series of push-button switches, each paired with a resistor to create a unique resistance value for the transceiver to recognize. The circuit operates on a simple principle: when a button is pressed, the corresponding resistor alters the resistance seen by the transceiver, allowing it to identify which button has been activated.

The construction of the keyboard is straightforward. It requires a durable enclosure to house the switches and resistors. The push-button switches can be mounted on a printed circuit board (PCB) or directly onto a perfboard, depending on the desired complexity and robustness of the design. Each switch should be connected in series with its designated resistor, which will be connected to a common ground. The signal wire from the transceiver should connect to the junction between the switch and the resistor.

The circuit diagram should clearly label each button, its corresponding resistor value, and the connection points to the transceiver. It is advisable to include a power supply connection if required, although most transceivers can operate with minimal external power for keying functions. This design allows for easy modification and expansion, as additional buttons can be added by incorporating more resistors and switches, provided that each new combination maintains unique resistance values.

Testing the completed circuit involves using a multimeter to verify the resistance values at each button press, ensuring that the transceiver correctly identifies each input. It is essential to ensure that the total resistance values do not exceed the specifications outlined in the transceiver's manual to avoid potential damage or malfunction.

Overall, this custom keyboard solution enhances the usability of the Yaesu FT2000 transceiver, allowing operators to engage with their equipment more effectively and comfortably, while also providing a rewarding project for electronics enthusiasts.The transceiver Yaesu FT2000 (as well as FT950 and FT450) supports 2 features: CW memory keyer and phone voice keyer. The keyers are operated from panel - small buttons in lower left corner. If you want to use that button often you soon find the buttons are too small, hard to access (mike connector obstructs), the horizontal pressing is not very e

rgonomic. Yaesu guys know that and therefore they offer a keyboard FH-2 that contains 12 buttons they guess the operator needs mostly. I don`t know, but I feel I need ofter only 5 of them, to recall all 5 stored messages. The rest is not used too often, I can press the panel buttons instead. So I decided to construct an own keyboard - I have been inspired by article in Czech HAM magazine (by OK1UKV).

It is quite simple. There are just switches and resistors inside the box - the transceiver measures the resistance between signal wire and ground, different value means different button. You can find a list saying which value corresponds to which button in circuit diagram (including for buttons that I don`t use).

I haven`t test how is the value critical - I just search thru my "resistor collection" and always found the two having resistance with less than 10 ohm difference while connected in series (but I think you can use less accurate resistance). To set the precise value using 2 resistors is much easier than to find one having exact value. The push switches are from "prehistoric" PC keyboard - the era before useless "rubber switches". But I am sure you find replacement easily.