We are announcing Version 2 of the EPM, Electro Permanent Magnet and the OpenGrab CAN daughterboard (OGCAN). A simple solution for cargo gripping for UAV’s and robots.


Introduction EPM V2

Operating principle explained in this video




Supported are RC PWM and CanBus with the CanAerospace daughter card. The EPM has an onboard PIC12F MCU with an in circuit programming header to allow easy reflashing.

Even lower power consumption; 400mA for 400ms at 5V per cycle or 800mJ.

On board tactile push button: Allows toggle testing the EPM on/off  having only the power connected

Cycle time: The Cycle time is 400ms or 2.5Htz. This solves the problem when the EPM is turned on and the target does not make perfect contact, the majority of the energy is used to move the target into  place rather than realign the magnetic domains, resulting in a much reduced holding force. With the fast cycle time one can turn the EPM on a few times in a row to make sure proper contact has been made.

Full bridge Thyrisotor drive circuit increases efficiency and reduces capacitor size .

Reduced magnetic interference allows mounting within 5cm of a magnetometer (please test it with your application)

Lighter- mass has been reduced to 47grams


Data sheet


Source Code / Parts Drawings

User Group / Help





Introduction of the CAN daughterboard 3689574886?profile=original

OGCAN is an open hardware CAN bus interface that allows to control OpenGrab EPM and monitor its state via CAN bus or serial CLI. Supported CAN protocols: CANaerospace, UAVCAN (full UAVCAN support comes April 2014).

OGCAN is built on STMicroelectronics STM32F103 MCU running RTOS ChibiOS, implements one CAN bus interface (ISO 11898-2, up to 1 Mbps), one TTL UART for CLI and optional CAN termination resistor (via jumper). OGCAN can be directly connected to EPM via two board-to-board connectors, as shown below.

Supported CAN protocols: CANaerospace, UAVCAN"




Source Code






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  • Hello Marc,

    I looked into the case and your are right about the bad communication we should not have let you wait 4 days to replay to your email.

    So the thing is and I'll add clarification on our website is that 10% of shipments get lost and have to be resend. The mail system is not quit up to par with the Deutsche Post here in Nicaragua, there just no way around dealing with them unless one want's to pay quit a bit for shipping with EMS and even they are not that great either.

    I understand your frustration and we will be taking this matter up with the Corro de Nicaragua.

    Jeff should have gotten back to you when your shipment should arrive and your money is not gone, we will issue a refund if that becomes necessary. 

    I am very sorry that this had to happen to you

    Kind regards



  • Hello,

    I just want to share my purchase experience with the community:

    Ordered one item on february, paid with paypal. After 5 or 6 weeks nothing has arrived.

    So I wrote an email. Got an response days later. They said the will send it then.

    Now after 3 monthy I still did not get anything.

    Wrote an email again and now they don´t even answer anymore.

    Seems like the service and the communication is really bad.

    So my money is gone and I got nothing from them.

    Has anyone made similar experience with these guys?

  • MR60

    Indeed I need this wonder on Pixhawk!

  • Will the wiki need updated now that v2 has the PWM header?
  • Developer

    We've documented how to wire up the gripper to an APM2 on the wiki.

    The code didn't quite make it into AC3.1.2 but it'll be out for AC3.2 or before then with a release candidate.

    The news about CAN bus support is excellent!  That'll be good for integration with the Pixhawk.

  • Moderator

    Very nice and thanks for the video Euan - good demo.

  • No, the flight computer should issue commands either to the EPM or the OGCAN card. The plan is integrate this into ardupilot code as a mission command

  • If I read the 3.2 ardupilot advisory correctly (unlikely!)...will we need the daughter card to issue commands to the unit during an auto mission? Or is it envisioned that we will be able to program the PWM command as a waypoint?

  • The Can Bus daughter card only provides a Can Bus interface and it looks like it will become standard for everything within the year.

    There are numerous advantages with can bus, this is a good discussion on this:


    Google Groups
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  • (you can just see the lead in the corner of my last picture - attached straight to the base unit)

This reply was deleted.