I've completed the design of my pool timer that can turn the pump and light on/off via WiFi and would love to get my design reviewed.
At 120 V the pool light should handle 500 W. The pump is 0.5 HP. Since I'm using the HLK-PM03 as a power converter, I've also added a temperature and safety fuse for safety. Two MOVs are used to protect each relay, although the light shouldn't really generate much noise. There's a jack for a one-wire thermometer, another to program the ESP32 and three pins of extensions to future-proof the board if I ever need to add additional relays boards without the CPU.
The board will be mounted in a traditional pool enclosure and I plan to apply a conformal spray on it to shield it against moisture. The digital ground will be connected to the box's ground through the corner screws. The digital grounds are not connected because I'm creating two ground planes (front/back).
The PCB presented below shows a 1 mm grid for a total PCB size of 3"x3". I'd appreciate any feedback before I order the appropriate hardware.
- J1/J2 https://www.onlinecomponents.com/american-zettler/az215011a120ae-44256439.html
- MOC3063 https://www.futureelectronics.com/p/4780375?utm_source=octopart.com&utm_medium=cpcbuynow&utm_content=instock&utm_campaign=Octopart_Ext_Referals
- MOV1 https://www.digikey.com/product-detail/en/littelfuse-inc/V14E130P/F5357-ND/1009238
- MOV2 https://www.digikey.com/product-detail/en/bourns-inc/MOV-07D201K/MOV-07D201K-ND/2538095
- ESP32 https://www.digikey.com/product-detail/en/ESP32-WROOM-32U/1904-1026-1-ND/9381735?utm_campaign=buynow&WT.z_cid=ref_octopart_dkc_buynow&utm_medium=aggregator&curr=usd&site=us&utm_source=octopart
- R4 (470) https://www.digikey.com/product-detail/en/stackpole-electronics-inc/RNF14FTD470R/RNF14FTD470RCT-ND/1975003
- R3 (1k) https://www.digikey.com/product-detail/en/stackpole-electronics-inc/RNF14FTD1K00/RNF14FTD1K00CT-ND/1975018
- R5 (4.7k) https://www.digikey.com/product-detail/en/stackpole-electronics-inc/RNMF14FTC4K70/S4.7KCACT-ND/2617510
- R1/R2 (10k) https://www.digikey.com/product-detail/en/stackpole-electronics-inc/RNF14FTD10K0/RNF14FTD10K0CT-ND/1975090
- C1 (10u) https://www.digikey.com/product-detail/en/wurth-electronics-inc/860020672010/732-8856-1-ND/5728801
- C2 (22u) https://www.digikey.com/product-detail/en/wurth-electronics-inc/860020272001/732-8903-1-ND/5728846
- F2 (72C) https://www.digikey.com/product-detail/en/cantherm/SDF-DF072S/317-1124-ND/1014753
- F1 (200ma) https://www.digikey.com/product-detail/en/bel-fuse-inc/RST-200-BULK/507-1169-ND/809313
- F3 (630ma) https://www.digikey.com/product-detail/en/schurter-inc/0034.6042/486-2614-ND/640032
- crimp https://www.digikey.com/product-detail/en/molex/0192110003/WM18374-ND/279175
- HLK-PM03 http://www.hlktech.net/product_detail.php?ProId=59
- S1/S2 https://www.digikey.com/product-detail/en/omron-electronics-inc-emc-div/B3F-1000/SW400-ND/33150
- TERM3 https://www.digikey.com/product-detail/en/nte-electronics-inc/25-E400-03/2368-25-E400-03-ND/11647403 SW1 https://www.digikey.com/product-detail/en/te-connectivity-alcoswitch-switches/1825910-6/450-1650-ND/1632536
- I have chosen to place two ground planes on the digital side, one on top and another at the bottom. I was trying to figure out if ground loops would be an issue here. I could easily route the ground on the bottom layer if that's the case, but I like the cleanliness of the planes.
- My neutral is 4 mm wide everywhere except when it connects to the MOC since the pads can't handle that size. That said; the MOC won't take that much power so I connected it to a 1 mm trace instead. I'm assuming that should be fine.