Hi
I am building a rate counter that uses a photosensor/reflector type system to detect cans passing a point on a factory line.
I am using an ATMEGA8535 Micro to do most of the work and outputting to either 3 or 4 separate 4511 (BCD to 7 Segment) and through a ULN2003(per display) to the 2 inch (50mm ish) display segments. (Common Anode)
My Question is? Of course the ATMega and the 4511 will be working on 5v however the displays are on 12v (Each segment requires 8v to run). Is pin 9 on the uln2003's tied to the 5v or the 12v? Also is there any problem to tie the pin 9's from multiple displays together? (I am guessing it is ok to tie then together and to the 12v but why I ask is because I saw a design for such an application with the pin 9 floating so I want to make sure before having boards manufactured).
Also I have found a pretty reasonable pcb house in china to make my boards (all through hole components) but can anybody suggest any other reasonably priced placed to get small runs of pcb's done?
Thanks
Bruce
I am building a rate counter that uses a photosensor/reflector type system to detect cans passing a point on a factory line.
I am using an ATMEGA8535 Micro to do most of the work and outputting to either 3 or 4 separate 4511 (BCD to 7 Segment) and through a ULN2003(per display) to the 2 inch (50mm ish) display segments. (Common Anode)
My Question is? Of course the ATMega and the 4511 will be working on 5v however the displays are on 12v (Each segment requires 8v to run). Is pin 9 on the uln2003's tied to the 5v or the 12v? Also is there any problem to tie the pin 9's from multiple displays together? (I am guessing it is ok to tie then together and to the 12v but why I ask is because I saw a design for such an application with the pin 9 floating so I want to make sure before having boards manufactured).
Also I have found a pretty reasonable pcb house in china to make my boards (all through hole components) but can anybody suggest any other reasonably priced placed to get small runs of pcb's done?
Thanks
Bruce