Let's Make Robots!

Spurt - Line following Beambot

Line following

Spurt is a brainless line following Beambot. It is based on the Spurt-Mobil from the University of Rostock / Tech. University of Berlin. It is a very cheap robot platform, easy to build.

Parts needed:

  • 2x motors Mabuchi FF180 12V
  • 2x rolling bearings 680
  • 6cm round bar from beech 8mm
  • 2x wood dowels 8mm
  • 1x ballon
  • 2x BC337 NPN transisitors
  • 1x CNY70 photo reflex coupler
  • 1x 1.2kOhm resistor
  • 1x 470Ohm resistor
  • 1x 47Ohm resistor
  • 1x 9V battery
  • 1x  battery clip
  • 20cm wires red/black
  • 1 piece of veroboard
  • 3x 2pin headers/female headers


The scematic is quite simple. The CNY70 refelective sensor is connected to transistor T2. On a white surface the photo transistor is on and T2 drives the left motor, T3 is switched off. On a black surface the photo transistopr is off and T2 is switched off, too. T3 is switched on, driving the right motor. This is how the robot is navigating between the black line and the white area.

All electronic parts has been placed on a littel piece of veroboard. It is easier to replace the electronics for further work.

The chassis is made of wood. An ice cream stick holds all the part, attached with hot glue. The motors have no gears. Lline shafts build from a ballon has been used to drive the wheels (standard inline skater rolling bearings).


Further work:

I think about a double line sensor board, a light follower board and an obstacle avoider beambot. Maybe a CPU based version later.

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hey! does 2 12V work good on just 9V??

Yes, it works. But as usual, 9V batteries don't last very long. Inoblegnome has made a different design, running at 3V with 2 AA cells. Look here: http://letsmakerobots.com/node/28235


I can't find those FF-180 Mabuchi motors at 12V. All the listings for the FF-180 I see are for 3V motors.

I see the FF-130 at 12V, and the FK-180 at 12V. Is it possible you used one of these?

I'm struggling with the more simple version that Spurt described in his post above. I would like to try one more similar to yours for greater reliability.

I think I have the FF-180PH 10320. It seems that Mabuchi no longer produces this type.

The Kemo P055 seems to be similar to this motor

This is the type shield

Thanks for posting the specs!

I think I might try the PC-130F-10370, available from Jameco. It's got good torque (which I think is the problem I'm having with my current motors), and a nice voltage range.

Current @ Max. Efficiency (A) 0.15
Efficiency 43.9
Nominal Voltage (VDC) 9
Shaft Diameter (inch/mm) 0.078/1.98
Shaft Length (inch/mm) 0.377/9.58
Motor Diameter (inch/mm) 0.803 x 0.984/20.4 x 25.0
Speed @ Max. Efficiency (RPM) 6410
Terminal Type 0.08/Solder
Voltage Range (VDC) 6-12
Torque @ Max. Efficiency (g-cm/mN-m) 8.5/0.83

I'm thinking about using this design for a workshop at either or both of the children's museum exhibit I'm planning or the NYC MakerFaire.

I wonder how cheap I can get those parts in quantity. If I could get it down to $5/bot, we could let people pay $5 to build their own bot and take it home.

Hi ignoblegnome, there are different types of the FF-180 motor, e.g. for 3 V. So you necessarily need to build a prototype with the very same type you will get shipped before you buy lots of them. Otherwise you could end up with a stock of parts whitch don't fit.

Good luck

$ 5 sounds very ambitious for me. Good luck for the exhibition.

By the way, "Spurt" is our abbreviation of: S chool P rojects u sing R obot T echnologies (this acronym works in english and in german as well):


Nice little bot,and I like the bearings and rubber band coupling :)  Aren't you using diodes to protect your transistors?