Gotchas WTF

A project log for Remote Control Mini Blimp!

Mini blimp flies through hoops! Features 3 DC motors/ propellers, battery charging, and wireless communication.

Sophi KravitzSophi Kravitz 02/09/2018 at 17:507 Comments

I designed an intermediary board to test out a new buck-boost voltage regulator, new motor driver, and a tag connect cable. For those of you in the ESPxxx forum, this is v2 intermediary board with EN tied to VBATT.

Here's the schematic, and the layout.

I intend to run the board with a single cell Lithium battery no less than 3.6V.

For testing, I am using a benchtop power supply (adjustable V, 3A) or a wallwart (5V, 1.6A).

The new voltage regulator, ADP2504, can provide a current output (see diagram on page 6) of over 800mA at VIN 3.6V. The inductor is rated for 700mA. Capacitors are X5R type.

Screenshot of ADP2504 schematic::

So far, I have populated the board with the ADP and the ESP-12S.

These two weird things are happening:

With power input from benchtop > 4.6V, ESP is able to program and hold the program. Under 4.6V, it is iffy, meaning that the program does not run all the time. Same (expected) results with wallwart at 5V. 

Current draw after ESP reset is less than 60mA, but sometimes (often at lower voltage) the current draw jumps up to as much as 210mA.

Does anyone have an idea why this could be happening? 

UPDATE: benchtop power supply is wonky and gives inconsistent readings, shuts off randomly, and probably puts out  inconsistent power. My best guess is that its constant current output is stuck on something not desirable. I've had it for over 8 years, so....

To add to the gotchas:


The ESP8266 can source 12mA on each GPIO pin. Maximum Drive Capability spec page 15.

Grabbed this from the forums:

12mA per pin source

20mA per pin sink

Total: 12mA x 16 GPIO


d1210reeves wrote 04/19/2018 at 14:57 point

im single and looking for a girlfriend

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jlbrian7 wrote 04/05/2018 at 10:35 point

Do you have a link to the hot air gun you have?

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jlbrian7 wrote 04/05/2018 at 22:13 point

i bought this in  january f

I haven't had any issues with it, but i am wondering if these cheap chinese tools use the same cheap chinese components.  it would be nice to find the manufacturer of the air guns so that components could be replaced easily.

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Sophi Kravitz wrote 04/05/2018 at 22:37 point

@jlbrian7 Agreed! I need to open up the nozzle and see exactly what is making the awful noise. Could just be a loose nut on the fan...

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Sophi Kravitz wrote 02/25/2018 at 22:31 point

ADP2504ACPZ-3.3-R7CT-ND is buck boost. ESP-12S is Wifi module. I have an oscilloscope :) See update, my benchtop power supply + probably some mechanical/ heat issues soldering the QFN over and over. All working now though. 

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Jarrett wrote 02/25/2018 at 19:03 point

What's the exact part number of the chip you're using?

Do you have access to an oscilloscope?

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