electronicsfreak
Member
Alright, here is what the project is. it will be once completed a simple chronograph which will calculate how fast an object can fly between the two gates (phototransistor/white LED) it will then either display the speed or the time that it took for the object to travel between the two gates on the three 7segment common anode displays through 3 CD4026AE's with transistor IC's now I know that the counter works when all of the certain pins on the first 4026 in the chain are connected directly to either 0v, or +4.5VDC (shown in the video on the link below.)
YouTube - 4026 counter
(i made sure I was dicharged in the video before I touched the counter)
Here's my problem. When it is connected to the microcontroller it doesn't do what it is suposed to do. when it turns on (in the program), it has all of the outputs off until one of the switches is pressed--which should just display the three decimal points as the displays are common anode. Instead, it displays the 000 as if the screen was enabled, and then finally after about 25-30seconds everything goes dark leaving the three decimal points. During the whole time pressing the input switches does nothing.
This told me that it was an oscillator problem, but I've already tried swapping out the PIC as well as the 4MHz oscillator which does nothing.
When you pull out the PIC and reconnect the necessary pins on the 4026 to ground/4.5v thecounter still works, I just cant get it to respond to the PIC.
I know that a very probable second problem that I will have is with the actual gates and if anyone has any suggestions on what to change please post them as well.
attached are the schematics, a photo of the circuit, and a program that should increment the counter every 2 seconds.
note----in the actual circuit the microcontroller is a PIC16F627, MCLR-pin4 is actually connected to +4.5vdc with a 56Ω resistor, and Vdd-pin 14 is actually connected to +4.5Vdc
YouTube - 4026 counter
(i made sure I was dicharged in the video before I touched the counter)
Here's my problem. When it is connected to the microcontroller it doesn't do what it is suposed to do. when it turns on (in the program), it has all of the outputs off until one of the switches is pressed--which should just display the three decimal points as the displays are common anode. Instead, it displays the 000 as if the screen was enabled, and then finally after about 25-30seconds everything goes dark leaving the three decimal points. During the whole time pressing the input switches does nothing.
This told me that it was an oscillator problem, but I've already tried swapping out the PIC as well as the 4MHz oscillator which does nothing.
When you pull out the PIC and reconnect the necessary pins on the 4026 to ground/4.5v thecounter still works, I just cant get it to respond to the PIC.
I know that a very probable second problem that I will have is with the actual gates and if anyone has any suggestions on what to change please post them as well.
attached are the schematics, a photo of the circuit, and a program that should increment the counter every 2 seconds.
note----in the actual circuit the microcontroller is a PIC16F627, MCLR-pin4 is actually connected to +4.5vdc with a 56Ω resistor, and Vdd-pin 14 is actually connected to +4.5Vdc