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Yesterday i got some progress. I changed crystal to external 20Mhz and i make flowchart more simple. I checked clock with led blinker and scope and it's ok. Also i tried 2k pull up resistor, but no change. How it works now: - LCD shows two temperatures, but both temperature values is from one sensor...

I don't understand why it doesn't detect my sensors. I'm 99.99% there is no problem in connections. What can cause this detection problem? I use 8Mhz internal oscillator, should i use something else? Here is my MCU configuration, is there everything ok? http://i5.aijaa.com/t/00222/13593401.t.jpg If ...

I tried to make it work with two sensors, but i get only error message.

Is there any simply example for two sensors. I have only that attachment example, but it is too confusing to me because there is only litle explanations.

Hi Ossir! I have a project with this device. As Ben say It something with the timing, and my experience with Ds18B20 Ben is right. I have only managed to get this att. project running. You can test it, and as it is with a Pic16f886 it work´s. But you can try to change the chip. The oscillolator is ...

Benj wrote:Hello,

I would change the Configuration oscillator setting from XT to HS to match the new 20MHz crystal.

Hopefully this should help things but let us know how you get on.

Same "CRC Error"

Benj wrote:Hello,

Can you attach your program so we can double check everything is ok there for you.

Here you are

Hi

I changed crystal to 20Mhz and now i get only "CRC Error". I double checked connections to sensor and if i disconnect the signal wire, then i get " No Device Found". Also i tried another DS18B20 sensor, but same results.

Hello I try to read temperature with Dallas 18B20 sensor, but i get always "-1.-6 C" readings (value not changing). I use "single one wire" example code with 16f887 chip and i have 4Mhz crystal and i use FC5. Here is how i connected it to chip. Port pin is A0, resistor is 4.3k an...

Hi

I tougth it's easier to do this with MCU. I found interesting site (http://www.esstronic.com/eprojects/ethanol/index.htm) and there is just what i'm looking for.
So maybe i try some of those circuits and see what happens.

Hi From your post the best suggestion i can make is to goggle megasquirt and have a good read. as just adding more fuel to an engine will in the long run only waste fuel and in all probability run worse than it does already. Regards Dazz No need megasquirt for this. There are products that work the...

Hello My plan is to make device which increase my car fuel injection (adjustable 0-40%), so then i can use E85 fuel.Basic idea is that, MCU (16f887) follows my car ECU injector signal and adds 0-40% to pulse width. Specs: - one input from ECU and one output to the FET which drive injectors - input s...

looking at the MAX232 datasheet, R1OUT can drop to 3.5V with a 3k load (~1mA) you might need to check the value of your R1 the MAX232 can sink more current, 3mA, so you might be better connecting the LED to 5v rather than 0v. Also that way the LED will flash on when you receive data I removed led r...

I tested Ben's flowchart with motherboard COM port and still i do not get letter to LCD.

MAX232 pin R1OUT voltage level is 3V, so should it be about 5V?

Here is my schematic.

Yes i have 5V, i connect it directly my pc motherboard COM port and try again.

Hello, Try this, I have modified your file slightly so it is hopefully easier to see whats going on. I also set the RS232 component to use the hardware UART which is on pins C6 and C7. rs232.fcf Let me know how you get on. Edit: Just noticed that i'm toggling portB 0 but this is also used for the L...

Hello I'm making relay board which can be controlled by pc with RS232. My plan is: - Board has 4-8 channel - I make software which can send letter "A" to MCU to control relays. - In the MCU code will compare that, if received letter is "A", then B0 go high or if received letter i...

Hello Martin

It seems to work similarly like in your simulation, so i'm happy with that.
Now i need to make some final adjustments and finalize the program.

Thanks a lot for your help Martin

Hello

Now reset button works.

If you have time, can you add comments especially in "after one second (yes) " in main program and also in LCD printing section.

Thanks

Hi Martin Now it seems almost working, there is couple of bugs what i notice: - Trip reset button not working - when input frequency is about 13.23Hz = 100km/h, speedometer shows 101.3km/h or 997.9km/h, correct value maybe 97.9 km/h Other questions: - Is there some way to measure how long 1 second i...

Hello Martin Program works in Flowcode but not in my circuit. I change LCD port to B and button back to D0 , but LCD prints only 1x 16 beams/bars. For me good resoluotion is 1km/h(speedometer) and 0.1km in odometer. I try to figure out tomorrow, why program is not working in my circuit. That would b...

Hi My main problem is tripmeter/odometer, not the speedometer. Like i sayd in my first post, I know that the speedometer resolution is not so good and like you said Martin in previously post, i propably add more magnets to get beter resolution. Specs/functions for my meter: - Speedometer, resolution...

Hi Ossi, On your hardware What value crystal are you using for you clock (have you got a part number for it)? Have you considered INT0 rather than a tight loop for detecting wheel speed? Martin Hello I use 4194304 Hz crystal and PIC16f887. These interrupts in program are new thing for me, so i dont...

I try to explain beter how the program works (in my opininion): - Program is based : Flowcode V4 examples --> 5. Digital frequency counter - It uses TMR0 interrupt (16 interrupts = 1s) - Macro "tulo" = input pulses from wheel - Macro "kello_laskutoimitus" = Timer calculations sec...

Hello I'm makin device for my dirtbike which measure time, speed and trip. Speed and time works fine, but i do not know how to measure trip correctly. Now the trip increases too fast compared to speed, about 1km in 10-20s if speed is about 60 km/h. Here is my program attached, so can somebody help m...