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Pull My Hair out, Optical Tachometer - PIC16F628A

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Try to erase and re program PIC.
initially it troubled me also, with similar observation. after a third reload it worked
 
I'll try that as well. Say I had something hooked up wrong. Could that possible corrupt or erase the program on the chip?
 
I'll try that as well. Say I had something hooked up wrong. Could that possible corrupt or erase the program on the chip?
it happened for me
dont have a scientific reasons for the failure
i was just interested why you are suffering ?
i wanted to simulate the entire set up here with only controller side
 
I'll try that as well. Say I had something hooked up wrong. Could that possible corrupt or erase the program on the chip?

hi,
The voltages that you posted suggests that PIC is not running a program.

If you wish I could write a simple LCD test program for you to try in the PIC.?
 
Would the program supposed to be able to work with the current setup? If you could that would definitely help.

Once again, thank you guys for helping me get this figured out. I tried everything I could think of on my own.
 
Would the program supposed to be able to work with the current setup? If you could that would definitely help.

Once again, thank you guys for helping me get this figured out. I tried everything I could think of on my own.
the controller element worked fine when i bread boarded
perhaps for you too. most places need decoupling caps.
 
Would the program supposed to be able to work with the current setup? If you could that would definitely help.

Once again, thank you guys for helping me get this figured out. I tried everything I could think of on my own.

hi,
This program:
loop:
initialises the LCD, displays a test message and repeats
goto loop

Change the dustin1.txt to dustin1.hex and program a 16F628A, lets know.

EDIT:
Checking your latest picture, I see that you are using polystyrene as a surface to lay your project on.?

Thats not a good idea, any brushing movements of clothing will create a static charge, you could damage your PIC or corrupt its program.

BTW:
If the last hex file I posted does not wake up your display, I will post a hex file that flashes and LED so that we can check the PIC.
 

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Well I tried your layout tonight ericgibbs. Stripped out the motor circuit and used only what is on your modified schematic. Here's what I got:

Original TACH.hex file: Solid top row, initializes, then single bottom right square blinking. (actual blinking/flashing)

Modified TACH.hex file (tacho2.hex): Solid top row, initializes, then solid top row blinking. (more of a slow pulse than a blink)

dustin1.hex: Solid top row, initializes, then solid top row blinking. (more of a slow pulse than a blink)

Here's the voltages I read:

LCD PCB Pins:
1 = 0v
2 = 4.4v
3 = 0.548v
4 = 0v
5 = 0v
6 = 0.04v - 0.07v
11 = 2.4v
12 = 2.4v
13 = 2.4v
14 = 2.4v
15 = 3.619v
16 = 0v

Chip Pins:
1 = 2.58v
2 = 2.54v
3 = 0v
4 = 4.82v
5 = 0v
8 = 0v
9 = 0v
10 = 2.48v
11 = 2.48v
14 = 4.97v

I've also attached some pictures of the layout on the breadboard. You can see the single top left sqare blinking during one of the hex file tests. I also got some more PICs in today and tried a brand new one along with the one I had. Same result.

I don't know what's going on with this. I read a lot about this stuff and it is all supposed to be really simple. :confused:
 

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Well I tried your layout tonight ........

I don't know what's going on with this. I read a lot about this stuff and it is all supposed to be really simple. :confused:
I tried the pic element on breadboard again. I felt it, a question of one or other wires not connecting properly in the breadboard.
I suppose that you have used thiner wires as he recovered from some cable.
I too had inconsistency of wires. After I sorted them, it worked nicely. I took two photos one with authors name and second showing the results
Thus it works on original software, only thing you need to do is have a 10 ohms from display contrast pin3 to ground.

why not go ahead with a board, that has the LCD connections in order and wires placed properly, in the artwork.

best of luck in proper setting up
 
hi dustin,
I would agree with Sarma regarding the use of the finished pcb, the project board layout is messy and prone to electrical noise etc.

On the pcb I would add a 100nF cap across the +V and 0V pins of the PIC , as close as possible to the PIC.

From Sarma's and my tests of the programs, it should work if the hardware is ok.:)

EDIT:
Checking the last LCD PCB voltage list pins 11 thru 14 now look ok.
 
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I did notice some of the voltages were fluctuating. So it does appear to be electrical noise causing this? Do my connections seem to be right on the breadboard?

I ordered some .1uF caps yesterday. I should get them today or tomorrow. I will also try some thicker wires for the LCD.

Thanks.
 
I did notice some of the voltages were fluctuating. So it does appear to be electrical noise causing this? Do my connections seem to be right on the breadboard?

I ordered some .1uF caps yesterday. I should get them today or tomorrow. I will also try some thicker wires for the LCD.

Thanks.

hi,
Electrical noise can cause problems on project boards.

You dont need thick wires to the LCD data pins, the signal currents are minute.
The twisted pairs are not required.
 
hi,
Electrical noise can cause problems on project boards.

You dont need thick wires to the LCD data pins, the signal currents are minute.
The twisted pairs are not required.
Thick wires I meant to suite breadboard wiring, not to cause loose connections due to loose grip inside the bread board.
 
Thick wires I meant to suite breadboard wiring, not to cause loose connections due to loose grip inside the bread board.

I find that solid PVC insulated wire fits perfectly well in project boards, twisted multi stranded wire is unnecessary and prone to shorting.

This project does not require thicker wire for connecting the data/control lines of the LCD.
 
I find that solid PVC insulated wire fits perfectly well in project boards, twisted multi stranded wire is unnecessary and prone to shorting.

This project does not require thicker wire for connecting the data/control lines of the LCD.
Thanks, we generally use colored single strand 22swg wires for breadboard connections
 
Thanks, we generally use colored single strand 22swg wires for breadboard connections

Thats exactly what I use, stripped down solid strand 'old' telephone cable is ideal.

I would never use multi stranded wire as Dustin has used, especially using two wires twisted together.
 
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hi dustin,
I would agree with Sarma regarding the use of the finished pcb, the project board layout is messy and prone to electrical noise etc.

On the pcb I would add a 100nF cap across the +V and 0V pins of the PIC , as close as possible to the PIC.

From Sarma's and my tests of the programs, it should work if the hardware is ok.:)

EDIT:
Checking the last LCD PCB voltage list pins 11 thru 14 now look ok.

Thats exactly what I use, stripped down solid strand 'old' telephone cable is ideal.

I would never use multi stranded wire as Dustin has used, especially using two wires twisted together.

So what are you guys suggesting I try to get this working? Is my layout ok, if not what is wrong with it? Should I not be using a breadboard?

I'm stopping by the store to get some 22 gauge stranded wire to replace the wire on the lcd and some 24 gauge bus wire for when I make my proto board. Also picking up some .1uF caps to put in between +5v and ground on the chip.
 
So what are you guys suggesting I try to get this working? Is my layout ok, if not what is wrong with it? Should I not be using a breadboard?

I'm stopping by the store to get some 22 gauge stranded wire to replace the wire on the lcd and some 24 gauge bus wire for when I make my proto board. Also picking up some .1uF caps to put in between +5v and ground on the chip.

hi,
I would use the pcb for the project, the layout looks correct.
I am assuming from your pcb image that the copper track is on the other face of the board and that we are looking thru the board to the track.???

schematic...jpg
 
Correct, this is the component side. Well I had this setup laid out on a pcb and all I got what a steady solid top row on the LCD.
 
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Correct, this is the component side. Well I had this setup laid out on a pcb and all I got what a steady solid top row on the LCD.

hi Dustin,
I have just relooked at the pcb layout and the PIC/LCD tracks look ok.

I would add that 100nF across the PIC +V/0V pins, close to the PIC.

Use the Dustins.hex LCD file to program the PIC.
 
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