Originally Posted by wvgca
I went a slightly different approach on mine, just the sensor on the truck, no pcb, three wires up .. and no pcb for the nano ..three wires to sensor , and four to the current I2C display ..
I still prefer 7segment displays for visibility, but am currently trying double height numbers using both lines for the digits ..
I assume that you are running averaging on the speed, if the magnets are even 10 thou out of the correct angle, it will change the speed reading constantly..
The blue display does have nicer contrast than the yellow ones that I have
I'm trying to make something for sale, so PCBs are a necessity. Unfortunately, the most expensive part is the power pickup truck. Almost all the other parts are Asia purchases.
I originally started to use 7 segment displays, and I have about 300 of them laying around from other jobs that I did, but they are power hogs, requiring 20ma per segment, so worst case was almost 400ma for the whole setup. I started to use a LM317 regulator, but dropping 11volts at 400ma was just too much heat to dissapate(4+ watts), so I went to a DC-DC converter and the LCD display. Even when I add the 433mhz radio(running at minimal power output), the current load will be less than 100ma or so. With +90% efficiency of the buck converter, the thermal load is acceptable for mounting inside an HO scale or larger car. I've decided that N-scale isn't practical, as the radio or display is just too large......