Upgraded to wordpress 3.2. Quite painless.
Setting up the Timer
I received my components from digikey to finish the mesh based data collection prototyping. One of the components is the LTC6991 timer chip. I never soldered surface mount devices before so I did my share of reading up on it. Mine turned out functional but not the best looking. Hats off to those who make it look easy. The IC is TSOT-23 and I purchased a breadboard friendly board to solder it to.
[table “4” not found /]
Note US penny is same diameter as Canadian penny.
This chip is awesome and worked flawlessly. The datasheet has all the information and includes a sample-circuit for a self-resetting timer. The vendor also has an excel based calculator to facilitate resistor value calculations. It does not have provisions for the resistor/capacitor portion self-resetting portion of the circuit. One can refer to the datasheet to get the formulas to compute those. For my experiment, the circuit used from the datasheet is reproduced below.
I may have to lengthen the pulse duration later.
came to and I had a couple of 1% resistors available. Close enough.
The rest of the components values where calculated from the the vendor tool.
I wanted a period of 10 seconds and active low. That is a very high duty cycle that you would not get with a 555 timer. The final solution will have around 5 minutes between pulses but for testing purposes, 10 seconds is easier.
The output from the scope below shows (click on it for zoom). The period is 10.1s.