Electronics Projects

Low-power temperature and humidity meters

• On MSP430F4260 and SHT15 sensor. My first low-power device. Average current consumption is 22 μA. Uses built-in LCD driver.
• On C8051F986 and HIH5030 sensor. This is a really low-power one: current consumption is 1 μA. It uses two 2-digit LCDs for displaying temperature and humidity and an LCD driver based on CD4000 logic. The temperature is measured by a built into the μC temperature sensor.
• On C8051F996 and HS1101L sensor. Uses a 3-digit LCD. Average current consumption is 0.8 μA. LCD driver is also based on CD4000 logic. The humidity sensor is interfaced with the Capacitive Sense unit of the μC. The temperature sensor is TC1047A.
• On C8051F996 and HCH1000 sensor. Modification of the previous design for a different humidity sensor. All other features are identical.
• On C8051F920 and HCH1000 sensor. The simplest circuit ever with a software LCD driver. Two powering options are described: the one with a built-in DC/DC converter (power consumption is 3 μA from a AAA battery) and the one with powering from a 3 V battery (current consumption 0.7 μA).
• Solar powered with Cymbet lithium battery charge controller. The device is also based on C8051F920 and HCH1000 sensor and utilizes a software LCD driver. The average power consumption is in a sub-microampere range.
• On RL78 microcontroller and HIH-6130 sensor. Uses a sensor with digital interface and 2-digit LCD. Average power consumption is 1.3 μA from CR2032 battery.