Power micro controller with 9V outlet converter

Hello, first of, I'm not using an arduino, I'm using a HiLetGo ESP8266 micro controller. I tried to plug it in to the wall using a 9V 1.5A DC converter. I see that my board is rated for a peak voltage of 12-16V. and recommended voltage of 5V, 10V max. I measured the voltage and current from the converter and I got a reading of 9.5V and 0.89A. Still when I plugged it to my micro controller, in the Vin and Gnd pins, I saw some smoke and the board stopped working. I'm planning on purchasing another but I would like to know what is a safe way to connect this. I do need around 9V to control a solenoid valve.

Thanks for the help.

Is the solenoid powered from the board?

aarg:
Is the solenoid powered from the board?

That is correct the solenoid is power from the board and controlled by the micro controller. I have an additional gas sensor which is powered from the micro controllers 3.3V output. According to the place where I bought the micro controller from (Amazon) the chip does have a voltage regulator, but I'm not sure what the max voltage is, but it has been stated that the peak voltage for this type's of chips is 12-16V. So IDK.

I think I'm just going to use a 3.3V voltage regulator. That should do the job correct?

I don't see yet how an external 3.3volt regulator could solve your problems.
The 3.3volt regulator on that ESP board might just be able to power the board itself when powered from 9volt, but not a lot more (like a gas sensor). 12-16volt could overheat the 3.3volt regulator.
Post a circuit diagram, showing how you want to connect things.
And links to the solenoid and gas sensor (voltage and current draw).
Leo..

This is the circuit I'm trying to build based on the circuit from bc-robotics.com

The circuit with sensor only and power through usb was working fine.

But as soon as I connected it to the DC adapter my microcontroller died, which is why I think a voltage regulator would protect that from happening correct?

The transistor in your drawing is connected wrong.
You have swapped the pins that you have labeled 2 and 3.

Assuming the sensor and ESP draw 180+100mA = 280mA,
then the regulator would have to dissipate (5-3.3)*0.28A = ~0.5watt when powered from 5volt USB.
That would increase to (9-3.3)*0.28A = 1.6watt when powered from 9volt.
Enough to shut down (or fry) the 3.3volt regulator (educated guess is that ~0.5watt is all it can take long term).
You must use an external 3.3volt regulator for that sensor.
Or power both board and sensor from a 5volt buck converter.
Leo..

Hi,
What are 1,2 and 3 on your TIP120, you should label them B for Base, E for Emitter and C for Collector.

If you have connected it with that pin layout in your diagram you have pins 2 and 3 wrong as described by @Wawa.

Can you post a picture of your project so we can see your component layout?

Thanks.. Tom.. :slight_smile:

Wawa:
The transistor in your drawing is connected wrong.
You have swapped the pins that you have labeled 2 and 3.

Assuming the sensor and ESP draw 180+100mA = 280mA,
then the regulator would have to dissipate (5-3.3)*0.28A = ~0.5watt when powered from 5volt USB.
That would increase to (9-3.3)*0.28A = 1.6watt when powered from 9volt.
Enough to shut down (or fry) the 3.3volt regulator (educated guess is that ~0.5watt is all it can take long term).
You must use an external 3.3volt regulator for that sensor.
Or power both board and sensor from a 5volt buck converter.
Leo…

Hello Wawa thanks for the suggestion. I already ordered a few 3.3V Voltage regulators, would it be best to power the sensor and microcontroller separately?

TomGeorge:
Hi,
What are 1,2 and 3 on your TIP120, you should label them B for Base, E for Emitter and C for Collector.

If you have connected it with that pin layout in your diagram you have pins 2 and 3 wrong as described by @Wawa.

Can you post a picture of your project so we can see your component layout?

Thanks… Tom… :slight_smile:

Hi Tom, I only have the micro controller connected to the sensor at the moment since my transistors haven’t arrived. But my microcontroller died after using the external power supply as in the second diagram. I got the pin numbers from this datasheet. I switched the pin order to prevent the connections from overlapping, sorry for the confusion. 1=base, 2=collector, 3=emitter

Thanks for the help

max_034:
Hello Wawa thanks for the suggestion. I already ordered a few 3.3V Voltage regulators, would it be best to power the sensor and microcontroller separately?

Yes, I think it's wise to only power the sensor from that external 3.3volt supply.
Leo..

AAfter installing the 3.3V voltage regulator everything works fine now. I still need to finish the rest of the circuit but I'm waiting for parts. Thanks