Connect arduboy with esp8266 or other arduino

Hi,

Is there anyone who has tried connecting the arduboy to another device to use the display and buttons as control and feedback?

I am assuming it is possible over software serial through the usb port?
Can you just hack a usb cable and put rx and tx in an arduino uno tx and rx for example?
Are there any known examples?

I d like to control an rc tank over wifi with the buttons and get sensor feedback on the display.

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No. The USB signals aren’t standard serial. You would need a USB master device at the other end.

The Serial1 RX and TX lines (Arduino pins 0 and 1) are unused and are brought out to pads on the back of the Arduboy’s circuit board. You could connect them to a ESP8266 and control them using the Arduino Serial interface.

Note that the standard ESP8266 is a 3.3V device so you may need a regulator for power and level shifters for the signals, to interface one to the Arduboy.

You could also connect these RX and TX lines to another Arduino (or any other device that can accept standard async serial signals). Again, you may need level shifters.

Are there programmable free pins to be found if you open up the arduboy? Did you get this info from any kind of documentation?

Any Arduino pins that aren’t used by the Arduboy are brought out to pads on the back of the circuit board. The function of each pad is marked on the board next to the pad.

Unused pins available on pads:

D0/RX
D1/TX
D2/SDA
D3/SCL
A4
A5
AREF

Most of the signals used by the Arduboy are also brought out to pads.

Hey thanks for the info man.

Upon opening the back plate I found the following pins to be easily accesible:

D0, D1, D2, D3

D15, D16, D17. Are these respectively A4, A5 and ARef?

On which arduino board is the arduboy based? Can I just solder on the pads you think?

I am really excited now, thinking i ll just solder an esp8266 to it and make a wifi enabled arduboy (with extra power supply ofcourse) :wink:

A quick check with the multimeter reveals that the vcc pin puts out 3,8V. So hooking up an esp8266 directly seems totally possible. I can only assume the pins output the same voltage.

No. D15, D16, and D17 are the SPI signals and are connected to the display.
A4 and A5 are under the battery, above RESET, GND and VCC. AREF is not an I/O pin. It’s used to provide a reference voltage for the ADC used by the analog inputs.

[quote=“Ruben_Speybrouck, post:6, topic:1568”]On which arduino board is the arduboy based?
[/quote]

It uses the Arduino Leonardo bootloader and so can be considered to be a Leonardo.

The Arduboy uses the raw battery voltage as VCC. It’s normally around 3.6V but can go up to 4.2V when fully charged (and down to about 3.1V when discharged). The ESP8266 is specified maximum 3.6V so you risk damaging by it running directly from the Arduboy’s Vcc.

You could use a low dropout 3.3V regulator, fed from the Arduboy’s Vcc, to power the ESP8266 but the Arduboy could still output up to 4.2V on its signals, so you would need some kind of level shifters on the output(s) of the Arduboy that are feeding input(s) on the ESP8266.

You are like a waterfall of useful info Scott!

So I think, based on what you said, the easiest way to add wifi to an arduboy is:

  1. Open the backplate
  2. Add a fatter lion battery
  3. Connect a wemos d1 (esp8266 based) mini board with 5v regulator built in to rx and tx (I assume d0 and D1) and GND
  4. initiate serial communications between the d1 mini and arduboy through serial.print and serialparseInt commands
  5. add new backplate and longer bolts.
  6. Done

Sounds about right?
I am going to try this, I ll get back in some days to let you guys know wether I fried my arduboy or not, maybe add an instructable if it works :wink:

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The WeMos D1 mini has an on board 3.3V regulator, which can be used to power its ESP8266 module, but you would still need to convert the TX/D1 signal from the Arduboy to a maximum of 3.3V to feed it to the RX pin of the WeMos D1.

For level conversion you could use one of these, which are available on eBay from various vendors.

If you’re going to put the WiFi module under the new backplate, make sure the backplate isn’t made of metal or it may block the WiFi signals.

After looking at the WeMos D1 schematic, I’m not sure it would be a good choice to use with the Arduboy.

  • It has an on board USB to serial converter which would only be used to program the ESP8266. At other times it would needlessly draw power and shorten the battery life.
  • The serial converter is connected to the TX and RX lines of the ESP8266 which may interfere with the TX and RX signals from the Arduboy.
  • The USB connector provides 5V to the on board 3.3V regulator. If the 5V pin were connected to the Arduboy’s battery and the USB was connected, 5V would be fed to the battery which could cause it to overheat and explode!

If I was doing it, I’d probably use a standard 3.3V ESP8266 module, a separate 3.3V regulator, and the level converter that I’ve already mentioned or this one.