Wednesday, 25 August 2010


Now I'm getting into the CAN bus I can really see the benefits, actually I could always see the benefits, I just couldn't find a free block of time to tackle the learning curve. Anyway, I have also added CAN connectivity to the ECU, again I had already designed in the necessary hardware, so all that was need was to add the firmware to the dsPIC code. Having the ECU on a CAN bus is going to be really useful, as it means I can tell the HexEngine when the Engine is running, and when the system is at pressure, or for example when the Engine is about to power off due to loss of oil pressure! For testing purposes I added a page to the VIC-E Control utility to display the engine status.

My last CAN hurdle, which no doubt will be the hardest is to get the Peak PC104 CAN card I have ordered installed and operational within the HexEngine Linux system.. this no doubt like all things Linux too me will not be as simple as one might hope. But for now its off to France for a long weekend break.

Tuesday, 24 August 2010

The CANBus Plunge!

After spending some time trying to get the communications running better on the valve controller boards (VIC-E) which were using a RS485 multi-drop serial bus at 921600bps, and my own protocol, I finally took the plunge and switched to using a CAN bus. I had made the pcbs with the necessary CAN hardware, so it was just a case of getting my head around the CAN bus protocol and deciding how I was going to use it on the Mantis.

I ordered up a USB CAN converter, a pretty cheap unit from (Blue device in picture above). Then I re-programmed one of the VIC-E units to simply transmit a message on the bus. It wasn't long before I had some satisfactory results, and after spending the rest of last week and the weekend working on the CAN / VIC-E conversion its pretty much done.To simplify things, I have left the configuration of VIC-E under RS485 control, and the position and feedback via CAN. This means that to change PID settings I plug in a USB to 485 converter to the VIC-E, change settings and can test the output result by driving the valve through the CAN bus interface.

I have written a new windows application to control the valves via the CAN bus, and changed the existing windows app that usees the RS485 bus for configuration.

CANBus Debug View

Thursday, 19 August 2010

A quick 360 video

Shot this video while Josh was testing out the pilot position :)

The Mantis Takes Shape

Front View, the legs are slightly too wide apart here
We set our selves a dead line to get the chassis components fitted and the cab structure in place at the end of this week. Also we wanted to fit the two front legs so we could get a good idea of the finished beast! We wheeled the chassis out of the workshop and took a few photos.. looks great, and sounds good too sat in the cab with the turbo diesel purring behind! Josh is off on holiday for a couple of weeks, and I am off for a long weekend in France at the end of next week. When we return its time to start plumbing up the chassis deck hydraulics.

Pictured here with better leg positions.

Friday, 13 August 2010

Electronics Programming and Test

I finally found some free time to program and test the VIC-E pcb's James assembled during his time with us. So far all the units have programmed up ok, and bar one short and a bit of clean up have all worked.

One of the VIC-E modules under test.

I am still having issues with part of the code on the VIC-E unit, in particular when multiples devices are polled for data. I need to sort this out as it is a fairly important feature! I'm also considering adding CAN control, although not essential, I think it would make life easier in the long term.

A painted chassis

My Dad very kindly met me at the paint shop this morning to collect our powder coated chassis so Josh could continue with the build. The matt black finish looks great, more satin than matt but that was expected. If only we had of know that when we had the legs powder coated satin, which came out more like gloss!

Tuesday, 10 August 2010

May as well make use of the comfy chair!

Josh makes good use of the operator chair while drilling the 500 side holes into the femur and tibia cheeks. Its a two man operation, I load the legs onto the jig, and slide them into position while Josh lines up the holes and drills.. this will take some time!

Assembled Tibis

Six shiny new tibia assemblies.

Femur & Tibia Drilling Jigs

The Tibia drilling jig ready to go.. only 500 holes to drill and tap!

Josh and the first of his coxa babies!

Josh begins assembly of the first of the coxas, looking good silver anodized!


Pewatron Inclenometer     

Wednesday, 4 August 2010

Cab & Chassis Update

Chassis Front View Nurf Bar
Chassis Top View with A Frames

I have been in Sweden for the last couple of weeks, setting up an animatronic performance system for one of my film clients. While I have been away Josh has made good progress on the Cab design and chassis layout. The A frames and nurf bar are finished, and the fixing plates and oil tank/battery and fuel tank layout are looking good.

Oil Tank & Batteries
Bulk Head with Fuel Tank

Cab Design with side bars

I will return at the end of this week, and we will take the chassis off to be painted. With the chassis gone we will have some room in the workshop to finish the fixing holes in the leg cheeks. For this we have a ply wood jig currently being CNC cut.