Bugbot is small bluetooth conrolled robot. It's very fast
Step 1: Short Story of Long Build
Why long build?
Because at the beginning I wanted to build a small quadcopter, on the image above you can see my printed frame for it. When I put motors in this frame I realize that the are too weak for this.
Then I thought about a small hovercraft, again I designed a frame, tested it out and it works! So I made a PCB for it. When I connect everything to PCB it's stopped working because it was too heavy and transistors didn't give as many current to the motors as straight from battery.
So my last idea was to make a small robot which can be bluetooth controlled (because I had this PCB). Of course RPM of my motors was too big to place with normal tires so I thought to place them at angle of 45 degrees and add a piece of isolation as a small tire. And it works perfectly!!! Finnaly after 2 weeks :)
So here you can read how I made it.
Step 2: Parts
Most important parts:
- Attiny45 you can also use attiny85 it's not so important
- bluetooth module
- small motors you can buy it here (together with small battery) or e.g. find it in old RC helicopter
- 3 transistors
- 3 diodes
- 3 resistor 1,2kΩ
- 3,7V Li-Po battery it need to be small the capacity is not so important I use 180mAh, bigger capacity = longer working time, when you buy motors from link above you have lipo together with motors.
- one 3D printed part
Step 3: 3D Model
You need just one print for this project, chassis. I takes 1 hour to print. You can also try to make it without 3D printer but it simpler to make, looks better and is lighter when is 3D printed
Step 4: Program
Before soldering you need to upload your code to microcontroller. You need to download arduino bootloader for attiny45 (here is very good tutorial about it). Then you can choose attiny45 and 8 mHz internal oscillator. For burning program you need USBasp or other programmer or other arduino (you can read about it in link above).
Task of the program is receiving data from bluetooth module and turning on and off motors. It use software serial because ATtiny haven't UART pins.
Step 5: PCB
As I mentioned before this PCB was made for hovercraft so there is place for 3 transistors/diodes/resistors but actually you need just two of them. On the second image above you can see which elements are unneeded. And below you can find eagle files. And if you are thinking where is microcontroller (attiny45/85) it's below bluetooth module to save space on the board.
Step 6: Assembly
After making a PCB and printing you can start assembly. First thing is to make a small hole at the front of chassis with file. This is hole for battery cables. Now you can put your motors in holes, remember to check direction of it. Then you can put a battery under the motors and close it with PCB.
I added piece of isolation to motor shaft as a tires and to front of chassis I stick a pice of tape to make it quiter.
Step 7: Android Application
I made this android app in android studio. Here you can just connect to your device and controll motors. The code of it is very simple and use just on activity. I added .apk file and complete project if you like to see it.
Step 8: Conclusion
At the end I want to say:
1. Be carefull while playing with it. It is very small and can drive below the ferniture and you will need to rearrange the furniture to get it.
2. Your cat/dog may likes it :)
Thanks for reading!