Sunday, February 26, 2012

Capacitive Touch Pad

I just got the Texas Instruments Capacitive Touch Pad accessory for the Launch Pad experimenter's board (P/N 430Boost-Sense1). It comes with a preprogrammed 20-pin chip with demo code to let you play with it right out of the box. There are no moving parts. It works by sensing the change in frequency a body (i.e. finger) effects upon a relaxation oscillator; the added capacitance lowers the frequency, which the microprocessor measures. This can work as a proximity sensor (just waving your hand an inch above the board wakes it up and causes the LEDs to swirl in a circle), and as a toggle switch (the center LED toggles on and off) and as momentary switches (the circle of touch pads) all via programming. The capacitive touch pad is $10, and you will need a LaunchPad board ($4.30).

My Utube video of playing with it [Link]

T.I. Capacitive Touch Pad [Link]

My other interests [Link]

Saturday, February 25, 2012

RF Booster Pack for LaunchPad

Texas Instruments (TI) just came out with a RF Booster Pack for the MSP430 LaunchPad experimenter system.

The CC110L RF BoosterPack is a low-power wireless transceiver extension kit for use with the Texas Instruments MSP-EXP430G2 LaunchPad development kit. Based on the CC110L device, the on-board Anaren Integrated Radio (AIR) A110LR09A radio module with integrated antenna operates in the European 868-870MHz and US 902-928MHz ISM bands. The included software application, called AIR BoosterStack, demonstrates an example sensor network as well as network status reporting.
Download updated and additional documentation and software from Anaren.
NB! Note that you will need two MSP430 LaunchPad kits in addition to this kit in order to use the hardware as described in the Quick Start Guide.

This is really inexpensive, $19.00 purchases a pair of transceiver boards; you will also need a pair of LaunchPad boards at $4.30 each. The software loaded easily, and within a few minutes I had a wireless link established between on transceiver hooked to the PC's USB, and another battery-powered transceiver. I put the battery-powered transceiver into my refrigerator (the signal strength was still very good) and took measurements using the supplied GUI (graphical user interface).  This kit provides a good starting point to hack in other sensors for a wireless sensor system.

The Parts list [Link]

My other interests [Link]

Sunday, February 5, 2012

Powering Up Your MSP430 Project

The low power MSP430 line of chips run on 1.8V to 3.6V. When using the LaunchPad emulator, your project is powered off of the USB port of your computer. When you want to deploy your project into the 'world' an appropriate source of power is required. The chip is not tolerant of voltages above 3.7V. The whole idea of this line is to operate from batteries under low power for long periods for things like remote sensors. A 3.3 lithium coin cell would work nicely, as would a pair of double or triple A batteries in series. An intriguing solution I came across in the Pololu catalog is the BodhiLabs single AA step-up 3.3V converter. It is specified to supply up to 100mAs (your project should not use a tenth of that if it is 'low power') (the low power lab runs at less than half of 1mA) and I could find no discernible ripple on my oscilloscope of the supply in operation. Solar and energy harvesting are other good possibilities that I would like to explore in the future.

Pololu/BodhiLab 3.3V converter [Link]
All Electronic Corp Coin Cell Holder [Link]
My other interests [Link]