CO Sensor with processor and Bluetooth transmission

Near “out-of-the-box” solution for complete CO (or chemical/gas) sensing with Bluetooth

I just received a sample kit of a CO Sensor solution from TI. If you need to design-in a CO/chemical/gas sensor with Bluetooth for a home, commercial or industrial setting, this solution could be a good fit.

It’s almost an out-of-the box implementation of a complete sensor with processor and Bluetooth transmission.

The kit includes the TI LMP91000 AFE Potentiostat as the sensor interface. The LMP91000 was designed specifically for use with electrochemical sensors, so you could design a highly accurate low-power blood glucose meter, blood alcohol measurement device, or pH meter using this chip.

The LMP91000 also features near complete configuration via an I2C port and has an external reference voltage input. The AFE Potentiostat can be used with either 2 or 3-wire sensors.

The next building block in this solution is the TPS62730 ultra low-power dc/dc converter for battery applications. This device uses a high-frequency dc/dc converter for low ripple, even with a small output capacitor. The TPS62730 is suitable for use with a variety of Li-primary battery chemistries as well as 2 AA alkaline cells.
It also features an ultra low-power bypass mode that can be used when the processor or SOC is in sleep mode. Typical current consumption in bypass mode is 30nA.

This device could be used in any low-power battery-operated design to reduce battery usage while providing reliable power to your circuit. The bypass mode allows you to get maximum life out of the batteries used.

The control in this solution is provided by TI’s CC2541 2.4GHz low-power Bluetooth SOC. This chip has an 8051 core, either 128kB or 256kB on board flash memory, 8K of ram and many other features and peripherals. This is a true system-on-chip, implementing a Bluetooth network node basically out of the box. It also has a hardware I2C interface for talking to the LMP91000.

This chip has plenty of flash and ram for applications, plus 23 I/O, a 12-bit ADC and a UART. It could be used in any application where you need a SOC with Bluetooth connectivity.

The CO sensor solution is an excellent reference design for a Bluetooth CO sensor, but some external circuitry is required and some programming. It runs on 1.8-3.6v, features ultra low-power consumption, and uses a versatile configurable AFE.

The range available with Bluetooth might be a problem in some cases; if range is a problem you might look at the Chemical/Gas Solution, it is almost the same circuit with a 4-20ma current transmitter output. With the CO sensor’s configurable AFE, you could interface a variety of sensor types to this design.

There are application notes and reference designs [ here or on TI’s site] for most of the components used. But don’t think that TI engineers have done all of your work for you – most of the proposed designs still require some design time for external circuitry and programming for configuration. You can go to the TI web site to download a sample kit.