The DS1669 is an electronic digital rheostat manufactured by Dallas Semiconductor. This component has a function similar to digital variable resistor/potensiometer which can be operated by push the buttons.
You can adjust the audio volume, LCD contrast, frequency, etc. by using two buttons instead of a common potentiometer/trimpot. This circuit explains how we do it with IC DS1669 IC. This IC is very popular and is widely used because it is a variable resistor that never wears down. By using S1 and S2 push buttons you can adjust the resistance. C1 is only a 0.1uF ceramic capacitor. You can use the datasheet of IC DS1669 to get more detailed information.
DS1669 Digital Variable Resistor Features:
- Replaces mechanical variable resistors
- Electronic interface provided for digital as well as manual control
- Wide differential input voltage range between 4.5 and 8V
- Wiper position is maintained in the absence of power
- Low-cost alternative to mechanical controls
- Applications include volume, tone, contrast, brightness, and dimmer control
- Available in 8-pin SOIC and 8-pin DIP packages
- Standard resistance values for Dallastat:
DS1669-10 ~ 10 k?
DS1669-50 ~ 50 k?
DS1669-100 ~ 100 k?
Download the Digital Variable Resistor DS1669 Datasheet: