I have an esp8266 controlling 3 relays. Thou I use a Transistor to trigger the relay, they still pull a lot of current from the 3v power supply when the coils are energized. I want to make sure that the esp8266 is protected from voltage spikes/drops but not sure what way I can do that.
I assume a Capacitor between the VCC and Ground would stop spikes and drops from effecting the esp8266, but not sure how to calculate the size?
Hi, and welcome to the forum.
An electrolytic buffer cap can stop a fast change (spike), but not a sagging supply.
More info needed.
How do you power the ESP8266 now.
What do you control/switch with the relays. Can you use a common ground and e.g. mosfets.
Maybe use a 5volt supply for the (5volt?) relays, and a 3.3volt regulator for the ESP.
Leo..
the plan is to use a Hi-Link HLK-PM03 Power module ratted at 3W
the ESP plus the three 3V DC 3W SONGLE Power Relay SRD-03VDC-SL-C
That should be about 600ma max
What worries me is when the three relays engage at the same time, the led's flicker
To Control the relays I use a GPIO to activate a NPN
Wawa:
Hi, and welcome to the forum.
An electrolytic buffer cap can stop a fast change (spike), but not a sagging supply.
More info needed.
How do you power the ESP8266 now.
What do you control/switch with the relays. Can you use a common ground and e.g. mosfets.
Maybe use a 5volt supply for the (5volt?) relays, and a 3.3volt regulator for the ESP.
Leo..
Drpepper124:
the plan is..
So you don't have one yet.
Drpepper124:
the ESP plus the three 3V DC 3W SONGLE Power Relay SRD-03VDC-SL-C
That should be about 600ma max
Should be ok for a 1Amp supply.
Drpepper124:
What worries me is when the three relays engage at the same time, the led's flickerTo Control the relays I use a GPIO to activate a NPN
How do you know when you haven't got the supply yet.
Switching supplies (like the one posted) have tight regulation, and usually don't like too much added capacitance.
100uF electrolytic might be ok though.
I suppose you did use a diode across the relay, a low saturation transistor, and the right value base resistor.
If you don't post a diagram and/or part numbers, we can only guess.
Leo..
Note that this module doesn't have much protection. People recommend to add current and thermal fuses and possibly a varistor.
Hi,
Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
So we can all be on the same page as to your circuit.
Please do not use FRIRZY.... 
Thanks.. Tom.. 
I built a prototype, and it works well, but I ordered the 3v relays from china(Still Waiting), and all I had was 5v, so I used one just to test with. The 5v is the one that causes the flicker.
.
I used a 1n4148 diode across the relay, and a 2n2222a transistor, and 470 base resistor with a 10k grounding resistor.
I will draw it up in eagle and get it in today
Thanks everyone for your help
OK, I just finished creating some diagrams in Eagle.
Sorry; These are my first Eagle Designs.
In General, this project is a two board set connected by a ribbon cable
the relay board goes into a 3 gang switch box. and connects to all the 120vac high voltage.
the switch board is connected to the back of a custom wall plate that has three touch switches
So What the Verdict Would a 100mf Tantalum Cap be a good addition at the esp82666 V+ and V- ?
Should I go with a Hi-Link HLK-PM01 (5v 3w) supply module. If I do that what would be the best solution to get the 3v 30 to 170ma draw from the esp82666?
On A Side Note, What would be a Good first Meter and Scope? There are so many options.. 
Hi,
Check this report.
http://lygte-info.dk/review/Power%20Mains%20to%205V%200.6A%20Hi-Link%20HLK-PM01%20UK.html
Tom.....
I looked at the report, it looks like a good device, and I should have enough reserve.
Is it a good practice to put a 100mg on the v+ v- of the esp8266 module?
I had this idea to include a diode between the power supply and the Cap, to trap the cap charge on the esp8266 side. Is that crazy?
What did you think of the schematics?, did I miss anything or do something dumb?
I tried to apply all the best practices I know of.
TomGeorge:
Hi,Check this report.
Performance test of Power Mains to 5V 0.6A Hi-Link HLK-PM01 UK
Tom.....