Magnetic Sensor on Pistons(help)

(Regarding the magnetic option for the free pistons off bimba)
What does the magnetic sensor actually do?
How does it send that information?
Is there a downside to getting it on the piston?
Is it removable if we decide to not use it?

There is a magnet on the piston inside the cylinder. Two removable sensors are clamped to the outside of the cylinder. The they trigger when the piston inside the cylinder moves under them. They have outputs that can be connected to the digital inputs on the robot controller. There is no downside i can think of.

I’ve ordered these before, and I’ve wondered if the magnet makes the cylinder heavier. Bimba’s website doesn’t seem to provide any helpful info. Any empirical data?

If it did, it couldn’t be more than a few ounces.


Not 100% sure, but I believe that all the cylinders have the magnet in them, it’s just a matter of putting the sensors on the outside. It seems like you can order those sensors alone. We have a few with the sensors in our shop, I’ll take a look at them.

Okay, I had previously thought that the only difference was that they include the sensors, but I wasn’t sure if they modified the cylinder. Thanks.

I believe that there are small magnets on the piston ring and the sensor is a switch that closes when the magnet passes under it and opens when the magnet is not near. As for weight it weight mere ounces and there is no drawback to them at all. You might have a problem with programming if running a program means meeting the condition of the switch being closed if you decide to suddenly remove it, so be careful to check your programming


It does alter the weight, but not by much. When you specify the magnet option, the piston inside the cylinder is extended by .15" to make room for the magnet ring behind the pressure seal. The cylinder wall is also extended by .15" to accomidate for this. The piston is made of aluminum and the magnetic ring is made of a pliable magnetic material similar to that which fridge magnets are constructed of.

Another question regarding the magnetic sensors:

Are you supposed to get TWO sensors whenever you order the magnetic cylinder variant?

Last year, we only got ONE sensor per magnetic cylinder.

  • Keith

Can u even use the actuater from last year’s kit?:confused:

Check the 2007 rules to verify this, but in the past as long as the cylinder is legitimate for this year’s contest, it doesn’t matter when you bought it.

The main areas to verify though are:

1) Is it still “unmodified”? (In the past, you couldn’t modify cylinders - have you done anything to it?)

2) Is it a legitimate cylinder for this year’s contest? (IOW, is it still on the “coupon” in the 2007 Pneumatics Manual? Normally, the only cylinders allowed at all are ones that match the coupon’s options.)

3) Does it conform to the FIRST part usage flowchart? (If it is on the coupon, then the answer should be “yes”, but check anyway. In the past there has been contradictory data between the Pneumatics Manual and the build rules. I see that this year’s 2007 Pneumatics Manual has “disclaimers” on each page, stating that “the contest rules take precidence” over it…) :smiley:

4) Does using it still keep you within your “max number of cylinders allowed” limit? (You’re normally given three FREE ones by the coupon, but the TOTAL number of cylinders allowed vary from year to year. See the rules for the decision on this year’s game. I believe we’re NOT limited in total cylinders this year…)

If you can answer “Yes” to all four questions, then you should be OK.

I hope this helps!

  • Keith