Coming soon: Accelerometer Support

[wildblue]

@dc42
I saw you implementing the upcoming support for a LIS3DH (3-axis MEMS accelerometer).

As it supports SPI and IIC, my question is whether both protocols are supported by your Implementation. I am with Duet2wifi (as you probably already know) and want to get this feature working on my machine. Can i order such a sensor yet or do you plan to switch to another sensor Platform?

I would offer to test the Implementation as soon my sensor arrives (If i am to order one, which depends ob your answer).

[o_lampe]

I was pretty busy with building MultiWii multicopter a few years back.
What I (vaguely) remember from then, is that the acceleration data is pretty inaccurate and the gyro-data tends to drift over time.
So they implemented a sensor fusion, where ACC-data was weighted with only 1-10%.
I'm surprised to see Duet want's to use ACC sensor alone? Seems good enough to figure out resonance...

[CNCModeller]

If I understand it correctly I believe the accelerometer is just a temporary fit of test instrumentation to gather the resonance data to set the relevant parameters. I don't think it's part of normal operation.

The multicopter uses the data to close a control loop which as I said I don't think is happening here.

[o_lampe]

@cncmodeller said in Coming soon: Accelerometer Support:

just a temporary fit

If so, what if I have a linear rail carrier with a growing flat spot on a ball? Wouldn't it be nice to detect the defect before it becomes an issue? IMHO, the accelerometer can do much more than 'ghost busting'

[CNCModeller]

@o_lampe said in Coming soon: Accelerometer Support:

@cncmodeller said in Coming soon: Accelerometer Support:

just a temporary fit

If so, what if I have a linear rail carrier with a growing flat spot on a ball? Wouldn't it be nice to detect the defect before it becomes an issue? IMHO, the accelerometer can do much more than 'ghost busting'

I'm sure there might be other use cases once the capability is available, I just don't think it's part of the current intent. I might be wrong, as I'm only guessing.

[o_lampe]

@cncmodeller
I didn't want to offend you, just looking over the fence (as usually beyond the horizon)

[CNCModeller]

@o_lampe said in Coming soon: Accelerometer Support:

@cncmodeller
I didn't want to offend you, just looking over the fence (as usually beyond the horizon)

Don't worry I didn't take offense...

[dc42]

@wildblue said in Coming soon: Accelerometer Support:

@dc42
I saw you implementing the upcoming support for a LIS3DH (3-axis MEMS accelerometer).

As it supports SPI and IIC, my question is whether both protocols are supported by your Implementation. I am with Duet2wifi (as you probably already know) and want to get this feature working on my machine. Can i order such a sensor yet or do you plan to switch to another sensor Platform?

See https://duet3d.dozuki.com/Wiki/Accelerometers for details of the accelerometer support that will be included in firmware 3.3beta3.

[CNCModeller]

@dc42
Is there a UK supplier for the SammyC21 development board?

I'd like to have a play with CAN on my Duet 3 mini and the accelerometer, but delivery from Germany to the UK is prohibitive for just one board.

[zapta]

@cncmodeller said in Coming soon: Accelerometer Support:

delivery from Germany to the UK is prohibitive for just one board.

There are inexpensive alternative with SAMD21G18. Will they work?

E.g.

https://www.seeedstudio.com/Seeeduino-XIAO-Arduino-Microcontroller-SAMD21-Cortex-M0+-p-4426.html

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=SAMD21G18&_sacat=0

[CNCModeller]

@zapta said in Coming soon: Accelerometer Support:

@cncmodeller said in Coming soon: Accelerometer Support:

delivery from Germany to the UK is prohibitive for just one board.

There are inexpensive alternative with SAMD21G18. Will they work?

E.g.

https://www.seeedstudio.com/Seeeduino-XIAO-Arduino-Microcontroller-SAMD21-Cortex-M0+-p-4426.html

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=SAMD21G18&_sacat=0

Unfortunately it looks lot me that they don't have a CAN interface... And even if they did I doubt the pinout would be compatible with @dc42 s firmware

I do have a teensy 3.2 with CAN but I'm assuming a transcode to that board is a massive task, even if it's fast enough.

[zapta]

@cncmodeller said in Coming soon: Accelerometer Support:

Unfortunately it looks lot me that they don't have a CAN interface.

I see, the CAN transceiver are external to the MCU.

Edit: In this case, an external CAN transceiver may help. E.g. https://www.aliexpress.com/item/32375462280.html

[CNCModeller]

@zapta said in Coming soon: Accelerometer Support:

@cncmodeller said in Coming soon: Accelerometer Support:

Unfortunately it looks lot me that they don't have a CAN interface.

I see, the CAN transceiver are external to the MCU.

Edit: In this case, an external CAN transceiver may help. E.g. https://www.aliexpress.com/item/32375462280.html

In principle yes if it's the right CAN standard, but it'll require new pin allocations in the firmware and TBH I'm not that interested in reworking @dc42 code.

I'm more interested in standing on the shoulders of giants than trying to be one lol.

[zapta]

@cncmodeller, let your inner giant free.

[wildblue]

@dc42 Okay, a LIS3DSH Sensor is ordered to connect via SPI on my Duet2wifi.

As i understand, the LIS3DSH should be also supported, because its only a more capable version of the LIS3DH. If not, there it goes to my bin of parts and 1.60€ down to the gods of tinkering. Just using the second position of this order (a true and only supported LIS3DH) then.

Just for planing things ahead, when will Version 3.3b3 be released?

I would love to add CAN-bus connectivity to my machine with Duet2 hardware. Is there yet a viable path to go for people capable of soldering and willing to tinker with their hardware?

[dc42]

@wildblue said in Coming soon: Accelerometer Support:

As i understand, the LIS3DSH should be also supported, because its only a more capable version of the LIS3DH. If not, there it goes to my bin of parts and 1.60€ down to the gods of tinkering. Just using the second position of this order (a true and only supported LIS3DH) then.

Unfortunately the LIS3DSH is not backwards-compatible with the LIS3DH, so the current firmware will not work with it. The control registers are mostly different, although the output and status registers are the same. So firmware changes would be needed to support it.

Just for planing things ahead, when will Version 3.3b3 be released?

As soon as I find a fix for the ADC/DMA issue in the Duet 3 Mini.

I would love to add CAN-bus connectivity to my machine with Duet2 hardware. Is there yet a viable path to go for people capable of soldering and willing to tinker with their hardware?

Unfortunately the SAM4E8E MCU on Duet 2 supports only basic CAN, not CAN-FD; so no. Even if it did, it has insufficient flash memory and RAM.

[Nuramori]

@dc42 can you share a quick diagram how you would wire up the LIS3DH with a toolboard? I have a duet3, and it's directly wired to a 1.0 toolboard right now (on the printhead). If I were to add the accelerometer, from what I am reading I need a sammyc21 also, but that all can reside on the printhead, but I'm not clear how it would chain up. I understand that the one side of the toolboard is terminated with the r120, so would that be removed and the sammyc21 put in the chain, with a termination after that?

[Nuramori]

@dc42 one other question, for the direct connection method, where you say to connect it to the SPI daughterboard, via MISO and MOSI. I noticed that the temp daughterboard connector also has SPI0_MISO and SPI0_MOSI connections - does that mean those could be used, AND also still connect a SBC, which has SPI1_MISO and SPI1_MOSI?

[dc42]

@nuramori said in Coming soon: Accelerometer Support:

I understand that the one side of the toolboard is terminated with the r120, so would that be removed and the sammyc21 put in the chain, with a termination after that?

Yes; or alternatively, connect the SAMMYC21 between the main board and the tool board, so that the termination resistor is still at the end of the chain. Or, if the SAMMYC21 is on the tool head so the wires between it and the tool board are short, just connect the SAMMYC21 CAN pins in parallel with the tool board CAN pins.

[dc42]

@nuramori said in Coming soon: Accelerometer Support:

@dc42 one other question, for the direct connection method, where you say to connect it to the SPI daughterboard, via MISO and MOSI. I noticed that the temp daughterboard connector also has SPI0_MISO and SPI0_MOSI connections - does that mean those could be used, AND also still connect a SBC, which has SPI1_MISO and SPI1_MOSI?

Yes, use the temp daughterboard connector to connect an accelerometer directly. The SBC uses a separate SPI bus. However, currently accelerometer data can only be saved to file when running in standalone mode.