Often when working with micro controllers 5V are needed. The ESP-01 however uses 3.3V and thus can't simply be connected to an Arduino or most USB/TTL convertes.
To fix this, I created this simple 5V breakout board for your ESP-01.
Step 1: The Basics
For the circuit you need the following parts:
- 1x low drop voltage regulator (I used a LF33 CDT)
- 1x 10µF capacitor
- 1x 100µF capacitor
- 1x 1k resistor
- 1x 1.8k resistor
- 1x 2 pin header (male) and jumper
- 1x 2x4 header connector (female - for the ESP-01)
- 1x 4 pin header connector (male or female)
- 1x piece of perfboard
The circuit is quite simple. The voltage regulator supplies the 3.3V to supply the ESP-01. The two capacitors are used to smooth the input and output voltages. Instead of the LF33 you could also use a cheaper LT1117 or similar. Refer to your data sheet for the correct capacities needed for those.
The TX from the ESP-01 can be wired straight through, because an Arduino or a USB/TTL adapter can work with the 3.3V input.
The ESP-01 RX however should NOT be directly connected to a 5V TX. For this we build a simple voltage divider with the two resistors.
The jumper connects GPIO0 to ground. This is used to enter the programming mode of the ESP.
Step 2: Soldering
Because the LF33 I ordered are on chip and not through-hole I first soldered small wires to it. This makes it easier to solder it to the perfboard.
Then solder everything to the perfboard. My soldering work is not the best so don't take it as an example ;-)
Step 3: Testing
Before you connect your ESP-01 you probably want to test your new breakout board. For this I use a basic 5V power supply. To measure the voltage I put a small cable into the VCC pin of the ESP-01's connector. Measure between the cable and any ground connector.
3.3V -- it works!
Step 4: Going Live
Now we will connect everything to the board. For this you should disconnect your power supply!
Just put the ESP-01 into the two-rowed connector. To communicate with the ESP I also connected a USB/TTL converter. Remember to cross connect the pins:
UART RX to ESP TX and
UART TX to ESP RX (where the voltage divider is)
You should also connect the converter's ground to the board's ground (the yellow cable)
Alright. Connect your USB/TTL to your computer and plug in the power supply. If the jumper is in place, the ESP is in programming mode and you can flash programs onto it (there are other instructables available for this).
If you remove the jumper and reset the power you should be able to connect the ESP to your serial monitor. Check your baud rate if you can't see anything or just scrambled characters.
And that's it. You can now use your ESP-01 with 5V and for example, connect it to an Ardunio.