ESP8266 Community Forum

- Tue Jun 13, 2017 12:57 am #67083

Where are you bypass capacitors? You should have 0.1uF capacitors across the supply pins of the CPU, across the ESP module, and also the regulator. I'm assuming U1 is a regulator. You need to add capacitance there. Look at the data sheet for the minimums for that device. And you should have a bulk capacitor. Like 100-470uF across each supply.

It seems that you are using a higher voltage supply for the CPU than the ESP. The rx into the ESP should not be higher than it's supply.

The ESP module should be rotated 180 degrees so that the antenna is on the edge of the board. Away from metal that will interfere with the radio signal but also to keep the radio signals from being injected into your circuit.

It is nice that you provided the circuit board information but a real picture of the final device would be helpful. Since you have the PCB layout then why not include the schematic? It would be a easier to read than trying to reverse engineer the circuit from the PCB.

I don't think that you should let the unused data lines on the LCD float. It may work but it isn't a good practice. I also wonder about the buzzer being on a port pin without a transistor buffer. Some buzzers draw more current than port pins can safely supply.

But it is working on bread board, without the capacitors? In our organization no provision(permission) to take picture, I can provide schematic if you want.

- Wed Jun 14, 2017 7:18 am #67152

But it is working on bread board, without the capacitors?

At least the power rails on a bread board provide a large capacitance (essentially they're two parallel metal strips).

Always follow the designer guidlines given by the manufacturer of a circuit, assume nothing.

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.

- Wed Jun 14, 2017 7:46 am #67154

But it is working on bread board, without the capacitors? In our organization no provision(permission) to take picture, I can provide schematic if you want.

ttirupathi, I have been employed designing electronic products for 32 year. I wish someone had told me that I didn't have to include capacitors in my designs. It would have saves a lot of money.

Just fix the things I said. Either that or do some research on your own.

- Thu Jun 15, 2017 12:12 am #67194

But it is working on bread board, without the capacitors?

At least the power rails on a bread board provide a large capacitance (essentially they're two parallel metal strips).

Always follow the designer guidlines given by the manufacturer of a circuit, assume nothing.

Ok. I have to redesign the pcb, I will do it. But even it works on the pcb (what ever I have provided(pdfs)) by connecting the esp8266 module with the jumper wires. All other modules mcu, 2x16 display, buzzar, push buttons, regulator etc are soldered on to pcb, and in place of esp8266 2X4 female strip burg I soldered and using male to female jumper wires of small in length(~40mm) connected the module. It works fine. But when I placed the module directly into the strip burg it is not working, even soldering the module also not working. mcu is continuously restarting, some junk character are getting displayed in the 2x16 display.