Tiny robot family

A family of tiny robots, each with their own way of life.

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This is my growing family of tiny robots based on ATtiny controllers, pager motors and photo-transistors.

These three little autonomous vehicles have a lot of similarities such as controller, battery and movement mechanism, and they all percieve the world through photo-transistor eyes. But they are all distinct designs with different capabilities and behaviors. They are the first members of a growing family of miniature robots that I have been playing with off and on for a long time

A key aspect of their design is at least one photo-transistor eye and one controlled LED. This allows them to interact in a meaningful way. Depending on how they are programmed, this could be as complex as data transmission between bots or as simple as interfering with the sight of other bots. The resulting interaction would also depend on the type of bots. For example, the eyes of robot 1 point downward to scan the surface, while robot 3 only looks forward.

At this point I have not programmed them for any complex interaction. Their main behavioral features are thus:

  • Robot 1 - Has left and right eyes looking down. Can detect lightness patterns on the ground. Here is a video of it acting as a line follower.
  • Robot 2 - Has one downward eye and one forward. Controlls a group of LEDs around its perimiter. It can see the lightness of the ground and look forward. It can also signal in all directions with the LEDs.
  • Robot 3 - Has one eye looking forward and two separately controlled LEDs pointing about 45 degrees to either side. It is supposed to be able to detect obstacles and determine which direction to turn to avoid them. I am still developing this feature.

The hardware:
The controller could be any of the 8-pin ATtinys. I have used the tiny85 because that's what I had on hand. I have considered a version based on the ATtiny10, but haven't gotten around to that. The batteries are LIR2032 rechargeable lithium coin cells that I pulled out of some solar key chain lights from the 100yen shop(dollar store). They don't last very long between charges, but I'm not planning on spending much money for fancy new batteries.
Here is the underside of each one.

You can see the 2N7002K mosfet transistors for driving the motors. There are also various resistors, capacitors and LEDs. The schematics are here:

The software:
At this point, the software is very simple, but it is easy to add another behavioral pattern in the code since the main loop simply calls a behavior function. Robot 1 has a line following bahavior. Robot 2 scans the ground and can signal to other robots in the area. Robot 3 avoids obstacles(still working on that one). I would be willing to upload the current code if requested, but since it is continually changing and far from complete, I won't put it here just yet.

If I make new robots, videos, changes etc. I will post a log here about it.

  • 1 × ATtiny85 Microprocessors, Microcontrollers, DSPs / ARM, RISC-Based Microcontrollers
  • 2 × 2N7002K MOSFET Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
  • 2 × small motors from andromedabots
  • 1 × some red LEDs
  • 1 × some ASDL-6620 phototransistors

View all 7 components

View all 2 project logs

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Dr PEKER wrote 04/21/2022 at 11:53 point

my IR-proximity sensor project may help to improve your robots enviroment sensing ;)

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agmartinezfarah wrote 07/18/2021 at 23:24 point

Buenas noches, me podrías dar información de programa de el modelo 2 y 3? Felicitaciones por tus lindos proyectos.  Atte. Andrés Martínez 

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Rudi24 wrote 05/09/2017 at 17:18 point

Can u make for Robot 1  HEX or BIN file ? i realy want to make that robot ,


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Rudi24 wrote 05/08/2017 at 21:36 point


i dunno what arduino is,but programming the code via ISP programmer directly to chip Attiny13 works?

i see 2 codes in log for robot1.

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Josh wrote 12/11/2016 at 20:18 point

Built these things after seeing your project:

Capable of programming and charging via usb

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Jed wrote 12/11/2016 at 18:22 point

Do you have to alter the code for the motors? I can't get my robot to function. I get the blinking led and once in a while it moves slightly. I did a breadboard version. Triple checked connections any ideas?

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nicoud jean-daniel wrote 12/11/2016 at 13:36 point

You know about PFM? see

and look at the Turtle project I just proposed - 18836-miniature-turtle-bot

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Rob wrote 12/10/2016 at 20:52 point

Have you thought of using two small solar panels to keep your battery charged?  You could position them to look like wings.  I once built a photovore that used capacitors instead of a battery.  The solar panels fed one large cap and two photodiodes fed into two smaller caps.  Whichever smaller cap was full first would trigger the larger cap to dump to a motor positioned on the same side.  The net effect was a light following bot that looked very similar to yours.

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Stephen K wrote 12/05/2016 at 12:03 point

I love the BEAM feel of these little guys!

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hgbutte wrote 07/17/2016 at 09:24 point

Great work !

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hgbutte wrote 07/17/2016 at 09:24 point

u can use a simple wire on a free port for collision detection !

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shlonkin wrote 07/17/2016 at 10:10 point

Nice. That's an effective and simple sensor. I tried that on another robot and it worked well.

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ndp516 wrote 07/03/2016 at 05:16 point

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patrickpoirier51 wrote 06/08/2016 at 11:20 point

Just update a Hockey Player nano bot Inspired by your work:

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shlonkin wrote 06/08/2016 at 11:49 point

That's a cool bot. I'm looking forward to future updates.

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electricpaw wrote 04/18/2016 at 08:24 point

Ooooooooooh, awesome! Yet small. As they say, greatness from small beginnings.

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JOhn gado wrote 02/06/2016 at 15:55 point

okay thanks

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JOhn gado wrote 02/05/2016 at 23:00 point

what did you used for the grip? What are these orange pad on the motor? 

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shlonkin wrote 02/06/2016 at 06:40 point

It's wire insulation from 22awg solid wire.

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jbird468 wrote 10/01/2015 at 04:27 point

Has anyone substituted the pager motors for tiny steppers like these?

Granted the circuit would be different(maybe via L293DNE or ULN2003AN) but at 0.36$ a pop encoded movement would be neat!

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starwriter wrote 06/30/2015 at 01:40 point

Any chance of getting the code for the other two little robots. ;)

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alexis wrote 06/08/2015 at 09:37 point

Neat little robots. Here is a similar project but I dont think its being worked on anymore. 

I think it had line following capability and a basic IR communication between robots.

Schematic, pcb, and code is all available.

They should have been used for testing swarm algorithms but we did not go very far, built a few dozen.

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shlonkin wrote 06/08/2015 at 11:58 point

Thanks for the link. Those are really cool robots. I was trying to get into that field of research a few years ago, but circumstances forced me to quit school and set all my dreams aside. 

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rylangrayston wrote 05/26/2015 at 02:49 point

hey I love these little line following bots and I have a few ideas for you that would make for alot of fun with them...
What if you used glow in the dark paper and UV LEDs so that each bot can both draw and follow lines, It would look just like the lines in this video, but the patterns could be some what emergent.

I would start out with some code like this:

if (folowingLine == true){



else { UVLED = 'ON' 



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shlonkin wrote 05/26/2015 at 10:57 point

That's actually a really cool idea. Ants behave in a very similar way and I've seen a few simulations based on just that same idea, but I've yet to see a physical experiment that didn't use actual ants. If someone tries it and gets some interesting results, they could publish a paper on it.

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