HP-01 available

[PANAMATIK]

Power consumption measured!

One important aspect for me of the "new HP-01" replacement is to give appropiate respect to the original watch and trying to keep their high claims entirely. A couple of highly skilled engineers were developing this masterpiece at a time, where they gave ultimately the best of what electronics could perform. They used much more dedicated hardware than today, they thought in single Flip Flops and gates, instead of modules to patch together. This gave the chips enormous power and performance even with low clock frequencies of only 800Hz ! in case of the HP-01. Today we can use multi purpose chips which lots of resources and MHz clocks to our service. Nevertheless it is still not easy to compete with the specifications of the original HP-01 and a challenge to choose the right components.

Now I'm glad that I got one goal confirmed. I measured the power consumption when display is off and processor is in deep sleep mode.



At 3.0 Volt it consumes less than 2 uA, as you can see in the image. Two SR44 cells in series will have nominal 3.0 Volt and claim to have capacities of up to 175mAh. I think you can get real 150mAh from them. This implies, that with two cells the new HP-01 will run about 79000 hours, this is more than 9 years. Of course you want to have a look at the time and the display lights up, this shortens the battery life. But it should give a good feeling, that the batteries will not be drawn empty when the watch is just waiting for its next mission somewhere at a party or meeting?

The original HP-01 used two cells for driving the display only, and one cell for the processor, in order to change the latter less often to keep the time running. My concept had to be different. I use two cells for both, display and processor, but in case you have to change the batteries, I provided a procedure to keep the time running during the replacement. So you never loose time and date, unless you wait too long for the replacement and the cells were completely empty.

Sleep mode is performing well and any buttons wake up the processor for some seconds and are processed immediately.

Next report will be about accuracy of date and time.

Bernhard