What an awsome little thing!
What an awsome little thing! I am truly amazed at it’s simplicity, size, and functionality. The rubber band solution is really a clever solution, and an easy way to do gear ratios on the cheap. Good job!
Very minimal and very
Very minimal and very interesting construction.
I am curious how you keep the rubber band on the wheels…guess it will slip off when the bot turns…
Thank you guys. In the
Thank you guys. In the beginning I was sceptical about the rubber band solution, but it works pretty well. As long as the motors and the axis were in parallel. OK, the rubber bands don’t last long, you have to replace it a lot.
**Inspired !! - Less is truly more **
Great little machine this - just goes to show what you can do with very little
Nice little bot,and I like
Nice little bot,and I like the bearings and rubber band coupling :) Aren’t you using diodes to protect your transistors?
Good point, Korel. I will
Good point, Korel. I will add some flyback diodes soon.
I’m learning too my friend 
I’m learning too my friend
You can get it smaller,
You can get it smaller, please look there: http://spurt.pbworks.com/Simpelmobil
Flat belts do not slip off
You can prove it by physics that flat belts dont slip of. Years ago the were used very widely: https://secure.wikimedia.org/wikipedia/en/wiki/Belt_(mechanical)
Physics tells that flat belts have the tendency to climb to the highest point of the pulley; wikipedia says: “Because flat belts tend to climb towards the higher side of the pulley, pulleys were made with a slightly convex or “crowned” surface (rather than flat) to keep the belts centered.” Indeed the bearings are flat, but a belt at the edge would “try to slip back”.
No Diodes needed here
Diodes would be needed if you had very rapid current alteration. But here all current alterations are much slow enough so you do not need diodes.
The Spurt Project
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):
I’m thinking about using
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.
$ 5 sounds very ambitious
$ 5 sounds very ambitious for me. Good luck for the exhibition.
Hi ignoblegnome, there are
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
I can’t find those FF-180
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
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
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.
| Specification | Value |
|---|---|
| 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 |
| Specification | Value |
|---|---|
| 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 |
hey! does 2 12V work good on
hey! does 2 12V work good on just 9V??
Yes, it works. But as usual,
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: https://www.robotshop.com/letsmakerobots/node/28235