Digital timer switches are used to control the operation of electrical devices based on a programmed schedule. This project describes a programmable digital timer based on the PIC16F628A microcontroller that can be programmed to schedule the on and off operation of an electrical appliance. The appliance is controlled through a relay switch. This timer switch allows you to set both on and off time. That means, you can program when do you want to turn the device on and for how long you want it to be remained on. The maximum time interval that you can set for on and off operation is 99 hours and 59 minutes. The project provides an interactive user interface using a 16×2 character LCD along with 4 push buttons.

1x 16x2 LCD Display with Green / Blue Backlight 1x PIC16F628A Programmed Microcontroller 1x LM311 IC 1x Accurate LC Meter PCB with red solder mask. Oct 28, 2017. The basic idea comes from the AN5. LCmeter_5_th.png' alt='16F628a Simple Program Code' title='16F628a Simple Program Code' />WinPIC Programmer 0. MB This is a simple program for Win9598XP to program the PIC firmware from a HEXfile into a PIC microcontroller. It supports JDM, JDM PIC.

Hi From what I can understand the circuit from Mark Weir is cyclic with a clock display. Im not a programmer but im rather technical thus I can build and write software to chips and the reason for this writing is I live on a farm and every day I need to start up a generator and switch it off at a specific time once during day break and once at night. I was thinking about a high power remote control but that will also lack in consistency.(old age keep on forgetting to do certain things) So I was thinking of a 24hour programmable clock that will start and stop this generator twice a day for me. If it is possible please help I like doing things for myself.

Thank you and God bless. Regards Philip. Ranveer i think you’re from India, I can tell you the cost of here Pakistan.

It should cost about 200-250 Rs.PKR So i think yours 100-150 i exactly don’t know the difference. Here microcontroller PIC16F628a is for RS 40 16×2 Character LCD is for RS 150 4pcs Button costs 20 Rs Resistance, crystal etc cost about 20 RS 2n3904 Transistor 3 Rs Piezo Buzzer 10Rs Relay 15 Rs Voltage regulator 7805 is for 7Rs and thats all now you can add some cost of the housing of your project. I think you better know about that. П˜‰ Keep doing good project.

I just finished this timer and everything works perfectly,thank you for sharing this project! To program the PIC16F628A i used a pickit2 with mplab v8.70,i loaded the hex file and then programmed the pic,this took me some time to learn how to do it correctly. Be very carefull when you make the circuit board because its very easy to do it wrong,check it twice. For the L7805 use a heatsink,for me it heats up very fast and i dont know why,guess its because of my relay i,m using a big one to controll a 3kW furnace. Thank you again guys for sharing this project!

Hi i want to ask if i use EEPROM.write(0,off(off_hh); and so on for all four values so does it make sense as if when start again so it read this firstthen go on to do the task by resuming. But while doing this i have a problem that i have to save the status on or off too but the insertion of those commands is really difficult for me could u please help me with this well u dont answer any of questions on ur blog u just tell that where i should tell it or else what variables i should not turn =0 so that all the setting never goes off thanks. Just finished designing PCB for this project in Proteus 8. If someone one wants to eliminate the crystal oscillator and load capacitors, you have to type PCON.OSCF = 1; // Set internal oscillator frequency to 4 MHz inside void main and before compiling in mikroc, select edit project, then change oscillator to INTOSC_CLKIN_CLKOUT. But when i did this in pic16f628a, the timing was off about 5 seconds per minute so i recommend using the xtal 4mhz crystal. The Proteus schematic diagram for Simulation is given in link below. I also did the PCB design.

I will update the design soon for the lcd backlight enabling and adjustment. Just finished this project and it works great after I figured out how to change the ext to int oscillator. Actually, I knew how to do it but it would not compile because it added some void main junk at the beginning of the file. I don’t know why it’s there but deleting allowed it to compile. I think it should be pointed out that the resonator or xtal is probably overkill for most applications and just running off the internal clock simplifies the construction a bit. I didn’t check the accuracy but I built this to turn off a battery charger after 12 hours and I am sure it is well within the one minute resolution of the display.

It should also be noted that you can get 5v USB chargers for 59 cents on Ebay so building the regulator part of the project can also be eliminated. These probably were not available when the project was designed. Thanks for the great design, Jack Marengo, Il. Error in the schematics: LCD-pins 7 to 10 *must* be tied to GND! This is *first learning lessons of electronics*: never leave inputs open!

@Marc: I’ve not yet built this project. It’s a pitty, the author R-B doesn’t answer to our questions anymore! Also note that the LCD-routines are built into library-files of MikroC Compiler. If you use this brand, you’ll never know how the source code looks like. No chance to get the source code. So if you want to be independent: write your own library, or much better yet: write it in assembler code, there’s many many examples out in the internet.

I can see after reading ALL of the comments that you are asked to redo code, send hex files, send two assembled programmable switches (Really?), et. I will not bother you again with asking for new code. I can figure it out well enough to use a different C compiler as you don’t seem to use any proprietary functions and I am not able to use MikroC on my older mac. Thank you once again for placing this in the public domain so that everyone may benefit. I will be using the LCD panel that is sold on piclist.org. It is very nice and already has the switches and LEDs. I will send you more information once it is complete if you would like.

Thanks again, Kevin. Hi, The circuit is OK, but when I set the configuration bits like X’tal=XT, master clear= enabled, and all others either off or disabled and the device=16f628A, using MP-lab and import the hex file it Programs and fails in the end and the message displayed is: Configuration Memory Errors Field: Code Protect Expected:Off Received:On although I kept Code Protect OFF, and when i again try by changing code protect to ON, it writes the files and when i place the IC to work nothing happens and the LCD is still blank. Please help me in thisThanks and regards. YES WE CAN USE BOTH MPLAB AS WELL AS MIKRO C PRO FOR SOURCE CODE BUT HERE ABOVE GIVEN PROGRAMME WRITTEN HAVE BEEN WRITTEN ACCORDING TO MIKROC, HERE THE LIBRARY FILES ARE IN BUILD FOR THE PROGRAMMER SO it is better to use mikroC pro programmer. Yes the source code written in MPLAB AS WELL AS MIKROC Pro are only be compiled in only that perticular software only as the library functions are defined accroding to software. Yes microcontroller only needs the hex file but the changes like the names and some other changes in the programme could only be done using source file. Yes you are correct A compiled code cannot be hacked or pirated for modification.

Hackers can only modify if they have the original source code either made by MPLAB or MikroC Pro. No, MPLAB doesn’t uses programming language different from MIkroC Pro.both uses the basic C language or we can also call it Embedded C. ” all the answers given above are according to my knowledge” one can use the Mazidi book. Im new to PIC microcontroller. Please correct me for this: 1.

MPLAB and MikroC Pro are kinds source code. I can choose either one of them. MPLAB and MikroC Pro have features to compile the source code file. If the source code is done in MPLAB it can only be compiled using MPLAB, same thing with MIkroC Pro. If source code and hex file are both available for free for a particular project in the internet, then no need to download the source file (unless I need to modify the code) because the microcontroller to be programmed needs only the hex file.

A compiled code cannot be hacked or pirated for modification. M68hc08 Serial Programmer Software. Hackers can only modify if they have the original source code either made by MPLAB or MikroC Pro. MPLAB uses programming language different from MIkroC Pro.

Can somebody please correct me with the above statement I have made. I’m new to this tutorial. As an electronic enthuasiast, I’m also interested to learn this nice stuff. By the way, what particular textbook should I study to be able to learn how to make a program or source/code. I want to learn how to make a program, wherein the PIC microcontroller will display time, will sense a temperature above 30 degrees and trigger a relay, log (tru EEPROM, but retrievable to PC tru USB port) temperature every 5 minutes. Congratulations to you R-B! Great project!

I am using Pickit2 right now to load the HEX file into the chip. Everything works perfectly! Since i want to modify the code a little bit, i will need to use the C source code. I have downloaded the mikroC PRO for PIC but I cannot get this software to work with pickit2. Do i have to use another programmer (like PRG-017 USB PIC programmer) in order to succesfully build and load the program or there is a way to compile the source C program using Pickit2?

Any help will be appreciated Thanks. Dupont, Although the programming language is C, the library functions are different in different compilers. This program can be compiled with MikroC. You can download the trial version of the compiler (that’s what I am using) from Mikroelektronika.

And while compiling it with MikroC, you have to create a new project and then copy/paste this source code in the editor window. Please read and MikroC user’s manual for further details.

I would appreciate if you will share your modified version with us in this blog, so that others may use it. Andrew, 22 uF was a typo, it is actually 22 pF. You will not see the crystal and caps on my board as I have used a 4.0 MHz resonator with/Cap, but I suggested to use crystal because it is more accurate. There is an additional transistor on my board because I didn’t have a piezo buzzer and so replaced it with a small coil speaker. But I recommended a piezo buzzer on my article because it can be driven directly through the microcontroller pin.

The diodes are general purpose ones, you can use 1N4148.