one change spurs another change

I exercise each day (unless of course I'm feeling lazy).  I've been using the Nordic Track ski machine for at least 30 years now.  But recently I decided to increase the time I exercise.  It didn't trigger any huge improvement in my health.

I realized that I usually watch the clock a lot while exercising.  I listen to Old Time Radio or Chapter a Day while exercising.  The Nordic Track has a speedometer/odometer/pulse sensor thingy but I hadn't been looking at it because the non-backlit LCD display was hard to see (due to glare).  

I was going to try building an analog speedometer (which I may still do) but first tried moving the Nordic Track speedo so that it was easier to see, this helped a lot.

I still look at the clock a lot but now I also check the speedo, too.  I've noticed that my step rate is well below 60 per minute and that the speed is usually below 7 kph, just inside the "green zone" of the Nordic Track speedo.  As might be expected when I concentrate on increasing the speed to the middle of the green range my distance and performance index increase.

So I thought: maybe some kind of a pacer circuit that I could synchronize my step rate to and not have to watch the speedo all the time.  The speedo is a little irritating because the reading bounces around a lot, the Nordic Track outputs only 1 pulse per rotation of the flywheel.

Although a PIC microcontroller might work well as a exercise pacer I found quite a few 555 based metronome circuits out on the internet.  This one looked pretty simple:

http://www.555-timer-circuits.com/metronome.html

I tried it on the solderless breadboard and it works fine but it'll need some tweaking on the pot, maybe add a series resistor and decrease the size of the pot to focus on the 45 to 60 steps per minute range ?  Also it wasn't loud enough with a piezo speaker, I may try it with a dynamic speaker as designed.

Interestingly I saw an article about how the 555 timer has a brief jolt of current every time the output transitions due to both transistors being on at the same time:

https://www.edn.com/the-ne555-current-spike
 

So I definitely will be adding some capacitors from the power pin to ground.

Anyway we'll see if the 555 metronome helps with exercise.

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm