Timeline for LD1117V33C and heat
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 9, 2017 at 5:49 | comment | added | Bruce Abbott | It's OK except voltage is set with a tiny pot which can be tricky to adjust (similar units that I bought had this problem). | |
| Jun 9, 2017 at 4:43 | comment | added | AndyD273 | What do you think of this one? I kinda think it might be better if I could get them somewhere besides China, as it's not much more, and I won't have to wait 4-6 weeks for it to arrive... I'm still waiting for my last order to arrive. It's been 4 weeks, so it shouldn't be too much longer. | |
| Jun 5, 2017 at 21:41 | comment | added | Bruce Abbott | I mean the one I linked to. It has a 3.3V output option, so could be used in place of your linear regulator. | |
| Jun 5, 2017 at 14:19 | comment | added | AndyD273 | @BruceAbbott According to the relay datasheet, the coil current is 141.67mA. If the HLK puts out 250mA, that leaves 108.33mA for the regulator. When you say switching regulator, do you mean the one I have, or the one you linked to? Maybe I should have gone with a solid state relay, but the price was a lot higher for the ones I was finding that could handle a 1HP load. | |
| Jun 5, 2017 at 7:15 | comment | added | Bruce Abbott | Another idea you might want to consider is using an Solid State Relay, some of which can operate on as little as 10mA @ 3.3V. | |
| Jun 5, 2017 at 7:10 | comment | added | Bruce Abbott | I looked back at your question and realized that I misremembered the PSU current as 300mA, so the current available would actually be 100-170mA. A 3.3V switching regulator would transform 100mA @ 12V into ~300mA @ 3.3V, so it might be OK (depending on how much current the relay draws). Your idea will work if you change the transistor configuration to grounded Emitter, with the relay connected from Collector to +12V and a resistor from GPIO to Base. | |
| Jun 5, 2017 at 5:53 | comment | added | AndyD273 | @BruceAbbott Was talking to someone in the chat and they pointed out that it wouldn't have enough current to run both the relay and the regulator, so I came up with another plan, and added a schematic. I don't know if it should be considered a new question at this point, since my original question was too ignorant... | |
| Jun 5, 2017 at 4:25 | comment | added | Bruce Abbott | Typical 12V coil current for a 30A relay is 80~150mA, so you have 150-220mA left to power the ESP-01. With an RC filter you may get away with the linear regulator, but it's not good engineering. If the resistor is large enough to drop sufficient voltage during receive then regulator input voltage will be critically dependent on current draw, and the transmit duty cycle will have to be kept very low. | |
| Jun 5, 2017 at 2:31 | comment | added | dandavis | you just connect the cap in parallel with Vin and Gnd. see this video for info | |
| Jun 5, 2017 at 2:17 | comment | added | AndyD273 | @dandavis Sorry, I'm not really sure how that would work? I'm still learning how to use caps effectively. | |
| Jun 5, 2017 at 2:15 | comment | added | AndyD273 | Good input. The relay is 120VAC 30A and rated for a 1HP motor, and so it is pretty big. I couldn't find a relay that could handle that kind of load with a smaller switching voltage. So if 300mA is the maximum draw... I'm hoping it'll be less than that. All I need is for the wifi to work, and for it to be able to send a small current to a transistor to turn on the 12V current to the relay. I really am wondering if it would be better to use the HLK-PM03, which has an output of 3.3VDC 3W, which is a lot more amps than I need, but IIRC if the ESP01 doesn't need the amps it won't draw them... | |
| Jun 5, 2017 at 0:53 | comment | added | dandavis | A 1000u caps will eliminate any wifi current spikes; keeping it at about 80ma. a 470u cap will keep the spikes under 200ma, within the limit of the regulator. | |
| Jun 4, 2017 at 8:19 | history | answered | Bruce Abbott | CC BY-SA 3.0 |