audioguru said:
Two rows of LEDs that meet in the middle?
You can make a tach from an LM2907 or LM2917 as an RPM to DC voltage converter. Then you use an LM3914 as a bar-graph voltmeter.
To get two rows that meet in the middle you put each partnered LED in series with the other one, for each output of the LM3914. :lol:
Thanks Audioguru, I wish it would make sense now but it still doesn't
Maybe I'm dense today and need to take more tablets :lol:
Anyway, here is how I imagine two rows:
1. one row above the other
2. one row at right angles to the other
3. one row next to the other
the "meet in the middle" bit could apply to option 3 but then you end up with ONE row.
When you mention partnered LED's, are you talking about two PARALLEL rows of LED's?
The tacho I built had a single long row of 60 LED's, connected, in the bargraph mode. The more LED's were lit, the highter the RPM.
I simply cannot imagine how to display RPM on TWO rows that meet in the middle and still make sense of it.
Or do I miss something here? A sketch would be appreciated :wink:
Klaus