I am completely new in designing circuits and PCBs and would appreciate your feedback on my first project.
I want to measure the current flowing through an AC line using the ACS712 current sensor (IC1). The analog output (which is a proportional voltage between 0V and 5V) is converted using an ADS1115 (IC2). The digital signal is passed to an underlying Wemos D1 mini board via I2C, which contains an ESP8266 to process and send the data to a server.
Furthermore, an AC/DC module (HLK-PM01) is mounted on the bottom side of the PCB to power the components.
Though I am happy to receive every possible feedback that comes into your mind, I have some specific questions:
- I am very uncertain about the AC part of the PCB
- Do I need to add some additional wholes or a gap between the AC and DC part in order to increase creepage?
- Do I need to add any specific components such as a fuse or varsistor?
- Is it common practice to exclude the ground plane around the header pins or is it fine to leave it as is?
Looking forward to receive your thoughts!
Update #1 (2017-07-17):
Here are some more information as required (thanks to @JackB for providing a list):
- Intended current --> ESP is rated at ~200mA. Added 100% buffer and calculated with 400mA
- Maximum fault current limited by fuse or circuit breaker --> need to google it first :D
- PCB copper thickness --> 1oz
- Line voltage in your country --> 230VAC
- Size of creepages and tracks --> DC tracks: 0.254mm, AC tracks: 1.016mm
- or size of the grid so we can work it out --> Grid 0.5mm
- intended operating environment (a plastic case?) --> Yes, something like this
Some more information as requested by @Asmyldof:
- using coatings? --> not planned. Are there arguments to do so?
- desired use case? --> using the attached ESP8266 I want to send the measured values via WiFi to a server
- which market approvals are you seeking? --> currently none. The PCBs are going to be manufactered in a very small quantity (10-20) and for personal use only (in this stage of the project).
- what are the connectors rated for under that body of approval? --> sorry, which connectors are you referring to?
- what board-size restrictions drove you to this layout? --> I want to put it into a typical "power meter plastic housing" (like this)
- what's under the board on the devices you want to plug it into? --> I didn't get that question