AN #35 - Low cost LCD frequency meter
Modified by Tomi - MCS Electronics
by K.S.Sankar - Mostek Electronics (
www.mostek.biz )
Originaly published in ELECTRONICS FOR YOU magazine ( INDIA - W W W . E F Y M A G . C O M ) Frequency meters have always been expensive tools for the average hobbyists. Now, with microcontrollers and liquid-crystal displays (LCDs) having become very economical and popular, it is possible to build a compact and low-cost LCDbased frequency meter that can measure up to 250 kHz.
A sample photo of the LCD module is shown in Fig. 1. These modules are available in 14- and 16-pin configurations.
The 16-pin module has a backlight option. Popular brands are Lampex and Hantronix. Note the pin numbers before soldering to the circuit. In this project, the LCD module used is Lampex LM16200 with 16 alphanumeric characters and two lines with backlight option. Pin details of this module are given in Table I. A
functional diagram of the module is shown in Fig. 2. However, you may use any branded or unbranded 2-line, 16-character LCD module for this project. The 10k potentiometer, which controls the contrast of the LCD module, works best when its wiper contact is nearer to ground potential.