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Topic: Help, loosing text on 20 x 4 LCD (Read 977 times) previous topic - next topic


:~  I'am new to Arduino, programing and posting. Trying to build a standalone flow meter. The .pde i downloaded uses a 16 x 2 LCD that i changed to a 20 x 4, I had on hand. It works, my problem is if I use the serial monitor or unpower the board i loose text and get garbage on the LCD. The only way to get the text back is to reload the sketch. Have the Arduino UNO R2 , attached schematic, data on LCD, and .sketch I changed for the 20 x4 LCD. Feel my problem is in programing or memory loss in the two counters. Any help appreciated and hope post OK with Mod's.

Thanks Ciawp


Thanks Don for reply. I read the post, most of it over my head. I did find after 5 to 10 resets average the LCD will display correctly. Also put ( delay 5000 ) after void setup but no change on reset tries. I'll try to reprogram pin 7 to pin 10 and pin 4 to pin 3 when i get time and post back.   Thanks again  Phil


Reprogrammed  not using pin 4 and 7, with delay statement. Unit needs reset about half the time from power-up ,otherwise seems to work OK. After reading many posts it appears the UNO R2 has some compatibility problems, someone correct me if I am wrong. I found a china made flowmeter around $20.00, think I'll try it for my project and go back to my latter-logic, getting too much education time for this old man.   



Phil, the answer for your issues... From another old man is likely to put the device in a metal box grounded and hang a 4700 uF 35 or 50 V electrolytic across the PSU output. It sounds like you are trying to deal with line transients when the pump is powered up. Make sure the leads from the sensor are well filtered. One low impact method I use is a 5 - 10 ohm resistor in series with the sensor lead and a 1nF (.001uF) cap from either end of the resistor to a local PCB ground. The filter is hard on fast rise time stuff and good for RF as well. It's time constant is too short for any effect on the measured signal. Make SURE your leads are Short and Direct to input, ground and output. In general always keep all wiring internal to the device bundled together all except the mains wiring as that is likely a source of fast rise time transients generated when the pump controller activates.

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