I know enough to be dangerous, i can build circuits and make minor changes but i am not an expert. I put this together after looking at schematics i have found online and i need some help getting the right components. The individual components i cant take credit for but i think the idea and final unit will be unique.
This is a speedometer for my 1950 Studebaker. It is a modern charging/ battery system. Should give between 11 and 14 volts. Both power supplies i have, the avr i am familiar with and have, i used it to control a skeeball machine. It uses a pulse generator on the transmission (new Dakota digital sen-01-1), i then modified the self powered sine to square wave circuit to run off of available power. I am hoping this will make it more sensitive. I am using the Russian equivalent to the Nixie drivers 74141.
1: i would like to control 2 of the elements without the need for a chip what should i do here? (mpsa42 and a 33k resistor? I have!)
2: Between the at mega avr and the 74141 (K155ID1)? do i need anything?
3: Do i need to do something special on the input voltage for these 74141 s?
4 and 5: I would also like to use ne2 lamps to replace my hi beam and left and right turn indicators. These are roughly a 12v signal i have 5v and 170v what circuit should i use? Hi beam may be on for long times. (tip 102?)
6: (not numbered on schematic) Is my use of the sine to square appropriate.
MY hand drawn schematic: http://i871.photobucket.com/albums/ab280/FortyTwo-edo/nispedov1.jpg
Sorry this is long but i have been looking at this for awhile and finally need to get it prototyped before snow so i can test it before i build the case.
Thanks
Ed Owens
Best Answer
1) I used MPSA42 transistors as low side switches in my Nixie tube clock. A 10K current limit resistor on the anode of the tube and (as I recall - schematics not at hand) a 68K resistor on the base of the transistor. The MPSA42 components are cheap enough that you can experiment with them.