A Cute ChatBot

Hello, and once again a more or less useful project.

We all know Alexa or LMM's like Chatgpt, Copilot and many others.

You can chat with them, but it looks boring when you talk to your smartphone or laptop. So now, drum roll, this incredibly cute robot. Now talking to large language models is finally fun and kawaii awrrrr.

Supplies Housing

• 3mm MDF
• 3mm acrylic glass, black tinted
• a bit of bread paper or tracing paper
• +- 35cm PG13 pipe for electrical installation
• 1.5mm electrical cable
• glue, screws, acrylic colors and spray colors

Design and Cad

As always, I visualised the idea in good old Google Sketchup and then used QCad to draw the individual parts. The whole thing does not have to be built one-to-one, but as always, it serves as inspiration.

You can find the plans here on my github https://github.com/awall9999/ChatBot/tree/main/cad

Build the Wooden Inside for the Face

As you can see, the interior is built in sandwich form. This allows me to distribute the light evenly and it is therefore possible to screw the entire control system onto this construction.

The screws serve purely as a positioning aid. The four nuts are inserted second last and are glued into the construction so that the plate with the LEDs can simply be screwed on. Now press everything together and wait until the glue is dry.

The Wodden Enclosure

First glue the small corners in place. The back panel is later screwed to these.

Then the side panels, the front and the base are glued together. Do not glue in the top section yet.

Let it dry first. Then take two scraps of MDF and glue the inner part in place as shown in the picture. The scraps of wood help to glue the part in exactly. Now the lid can be glued on and left to dry.

Body Paintjob

Now it's time to colour the main body, as it won't be so easy to do later. The cut-out parts for the mouth and eyes are taken so that no colour gets into the openings, otherwise the plexiglass parts will not fit later.

The MDF is sprayed black as a primer, sanded with sandpaper and a second coat of primer is applied. Then the whole thing was painted red. Looks good already.

Feet and Hands

The hands and feet are then glued together and painted black. A 33mm PG13 tube is fitted over each of the two parts of the legs that form a cross shape. The hands are glued together in three parts, with the centre part having the wood removed after drying. A wood screw is inserted here later to stabilise the whole thing. Finally, glue the two shoulder parts left and right onto the body.

LED Face Panel

The 3mm LEDs are sanded down a little at the front with sandpaper so that they distribute the light better and there is no hospot. They are then inserted into the plate with the 3mm holes. Soldered according to plan, the ram edges are also inserted here and everything is fixed with hot glue. The wires that go to the Arduino are also soldered.

Electronic

Part List:

• 1 Arduino Nano
• 1 Bluetooth Audio Module https://www.amazon.de/dp/B0B3TJ61M5
• 1 2-3W Amplifier https://www.amazon.de/Leistungsvers
• 1 Speaker 4Ohm 60mm https://www.amazon.de/dp/B0C1P8F1P2
• 15 3mm LED's
• 15 150R Resistor
• 8 4, 7k Resistor
• 8 BC546 or equivalent
• 1 100k Resistor 1
• 2.2uF 16V Capacitor
• 1 USB-C socket https://www.amazon.de/dp/B0CNWFLS6G

Assemble the audio module according to the plan. One channel from the Bluetooth module goes to the amplifier and the loudspeaker. The other channel goes to the A0 of the Arduino. The two circuit boards are glued to a small piece of MDF. I used JST 2.54mm plugs with cables and sockets everywhere for quick assembly and troubleshooting as this is my first attempt. But you can also solder everything together

Mount the USB-C socket and the speaker on the rear panel as shown in the picture.

I soldered the Arduino Nano together with the 4.7k resistors and the transistors on a breadboard. The 100k resistor and the 2.2uF capacitor too, of course. Then the LED board was soldered to the controller board. The whole thing is then scraped onto the intended MDF board with spacers and the LED boards are glued to it.

The Face

I laser-cut the bread baking paper and the tinted arcylic glass like this. The plexiglass is +-0.1mm larger than the cut-out in the front panel, so you can simply press these parts firmly into place as shown in the photo and the smiley face is finished.

Marry Electronics and Body

First insert the LED plate and screw it to the front with four 10mm M3 screws. There are M3 nuts in the front. The audio board is then inserted on the right or left and is held in place thanks to the 3mm sizing on the left and right of the front insert.

The Software

The software for the bot is not very complicated.

In principle, the value is measured at the analogue input from the Bluetooth module. If this goes above a certain threshold and stays there, then the LEDs from the mouth are switched on one after the other from the centre to the ends. When the analogue value is 0 again, the LEDs from the mouth are switched off again one after the other in a for-loop.

The whole thing runs in a timer loop. In this way, the eyes can open and close at random while the robot is talking. The eye-open time is longer than the eye-close time.

And that's it

The Software can be found here https://github.com/awall9999/ChatBot/tree/main/Software

The Final Step

Glue the two legs to the underside.

A 28cm long PG13 tube where you insert two twisted 1.5mm wires to be able to move the arms. Then simply pull the tube through the casing and fix it with cable ties.

Paint the two small round parts on the head silver. Wrap a piece of stripped copper rod as a coil, bend it a little and then glue it to the top as an antenna decoration.

Simply insert the hands into the ends of the PG13 tube. Do not glue them, otherwise you can no longer turn them.

Attach the rear panel with the speaker using M2.5mm screws.

A little drybrushing with silver paint and the ChatBot is finished.

A Few Beauty Shots

As always, my idea is expandable. I wanted to add a module that turns the voice into a robot voice, but unfortunately this is still travelling somewhere in the world by parcel post. Also, nobody needs to build it exactly like this. Build your own ChatBot, be creative.

I hope you enjoyed this build

Regards Alain