OddBot

Member Since: February 10, 2011

Country: Australia

Profile

Bio

http://letsmakerobots.com/user/1533

Role

Designer, adviser, all around bad guy.

Organizations

K.A.O.S DAGU LMR

Spoken Languages

English Chinese (kinda)

Programming Languages

Basic, C

Universities

This Universe (mostly)

Expertise

Electronics Desktop publishing breaking things

Interests

Educational Robotics Beer Goth / Geeky Girls

  • Product ROB-12075 | about 2 months ago

    I checked to see what spacers are included with the T'REX as another customer had the same complaint.

    Included with the T'REX controller are 4x 30mm and 4x 6mm brass hex spacers. When mounting in the Wild Thumper these spacers need to be joined together to make 4x 36mm spacers. This will hold the PCB high enough to prevent any short circuit.

  • Product ROB-12075 | about 3 months ago

    +Vi (+V input) needs to be the logic voltage used by the external controller. It can be from 1.8V to 5V and is used for the pullup resistors to the external logic. This allows any other controller to control the T'REX regardless what voltage it runs at.

  • Product ROB-12075 | about 4 months ago

    Be careful about changing voltage mode. Low voltage mode is only for 6V SLA, 7.2V NiMh and 7.4V(2S) LiPo batteries. If you use higher voltage batteries in low voltage mode then you can do permanent damage to the board.

  • Product ROB-10336 | about 5 months ago

    The mecanum wheels need to be drilled out to 4mm diameter. The mecanum wheels are not designed specifically for this chassis, they are simply the right size.

  • Product ROB-12075 | about 5 months ago

    Well that definitely looks like a mistake. The extra solder is placed on the tracks by hand to increase the current handling capacity of the tracks. If you have a soldering iron then you can just melt through the bit that should not be there. Otherwise, as the solder is soft you should be able to cut out the link with a sharp knife. Just be careful not to cut anything you shouldn’t :D

  • Product ROB-12075 | about 5 months ago

    The ACS712ELCTR-20A-T current sensors have an analog output however they need to be close to the “H” bridge which makes the analog output prone to electrical noise. If you are using a 7.4V LiPo then make sure you have the board in “low voltage mode”.

  • Product ROB-12075 | about 5 months ago

    These are all SMD FETs, there is no big tab to screw down onto a heatsink so yes, additional heat dissipation is done by the plastic body. I think you will find the engineers who designed these electrical components thought of these things and used a dense plastic that has relatively good thermal conductivity.

    Note that the board is only rated for 18A continuous per motor despite the fact that the “H” bridge FETs are rated at 85A each. The 4 layer PCB is designed to dissipate the heat evenly throughout the entire PCB thus becoming a heatsink.

    For applications such as the Wild Thumper and T'REX tank chassis which this controller was designed for, no additional heatsinking will be required.

  • Product ROB-12075 | about 5 months ago

    I can’t open your link so I can’t answer the question. I’m sure if you download the manual and read it carefully your question will be answered.

  • Product ROB-12075 | about 5 months ago

    There is a standard that all RC systems should adhere to. Essentially each servo signal is a pulse between 1mS and 2mS wide that is repeated every 20mS. A pulse width of 1.5mS is servo center. In reality the range of the pulse width and the repeat time can vary between different manufacturers.

    Unless your transmitter is made to a completely different standard then it should work fine. You can always tweak the T'REX sample code to suit your transmitter if required.

  • Product ROB-12075 | about 5 months ago

    Yes you can replace the PTC Fuses. You can get a bi-metalic self resetting fuse for cars and trucks. They are bulkier so you would need to mount them off of the PCB.

    For your application I think a heatsink and fan would definitely be a good idea. Although the 4 layer PCB does act as a heatsink this is really only suitable for the Wild Thumper and soon to be available T'REX tank chassis.

No public wish lists :(