Anyone with a Sinclair or MicroAce has experienced the hassle of having to check the TV screen after every entry to see if it got into the machine. Of course, there are those people with good peripheral vision who can manage this feat without bobbing their heads, but not me. So when I saw an ad for a “keyboard beeper,” I realized this most certainly would be a big help in entering programs on the membrane keyboard and sent for one.
The beeper comes assembled and is extremely simple. It consists of two integrated circuits, two resistors, and a capacitor mounted to a P.C. board barely larger than the components. The power and ground wires are connected to the ZX80 board just below the modulator on some wide power traces.
Five wires (which were twisted into a bundle) go to the keyboard side of the five pullup resistors at the extreme lower left side of the board. The order of sequence does not matter, as long as you connect to the side of the resistors that goes to the keyboard and not power. It is easy to see which side goes to the keyboard by just following the traces.
The last step is to install the small round piezo-electric transducer which produces the sound. The directions provided with the beeper suggest soldering one edge to the top of the modulator (the left side), so that is where I put it. The one remaining wire from the beeper board is soldered to the white portion of the transducer. I used a piece of carpet tape (not included in the package) to mount the beeper to the inside of the case top on the front surface of the “blister.”
The beeper worked perfectly the first time. Slight changes in the tone of the beep for different keys can be detected. This might be an asset if you have a good ear.
The real advantage comes when entering SHIFTed commands. Programming seems to go faster with less aggravation now that I know I am making good “contact” with the keyboard. I would certainly recommend the beeper as a definite improvement to the ZX80.
Keyboard Beeper, $12.
Burnett Electronics
908 Morris St.
Cincinnati, OH 45206