Load Cell Amplifier Input

Simucube 1 Simucube 1 Questions
1

Hi,
Does the Simucube include a load cell amplifier for high-end pedal input?

The release brochures indicate it does, but the web site documentation does not reference this at all (hence I assume the simucube is limited to voltage input from the transducer.

Thanks,

2

No direct interface unfortunately.

You need to run through a load-cell amp such as Bodnar or DSD sells.

3

As Phillip said it does not have the Load Cell Amplifier to boost the voltage to be read by a standard Analog Input so you would need one between the SimuCUBE and the Load Cell in order to use it.

4

Also such load cell amp would have to be operating on 3.3 V as the RJ45 ports are only 3.3 V tolerant.

One of the reason why the amps were not included on SimuCUBE is that the voltages they are supposed to be amplifying are really, really small, and long wires and noisy electrical environment on the SimuCUBE board would make the measurements inaccurate. Better to always use separate load cell amps as close to the pedals as possible. This is why the wiring length is often very short in load cell based pedals.

2 Likes
5

Fair enough.
Such a wealth of knowledge within this community and development team.

6

I wired a cheap 3 USD loadcell amp to SimuCUBE and the reading is very noisy, with a variance of more than 200 steps, tried earthing the metallic part of the pedal but it doesn’t help. The loadcell I used is a Mavin NA2. I wired a pot too and it works just fine.
Does Mika suggest I’ll be better off buying a Bodnar board?

7

I really do not know that much about loadcell amps. Could you provide the make and model for that cheap one?

8

Hi

Daceaki_chow, did you use 5V or 3.3V voltage as the supply for the load cell amp? The 5V has more noise than the 3.3V in simucube, and in any case, some electrical noise filtering is always highly recommended (if not mandatory) with external anlogue circuits.

It would be great if you could send pictures of the electronics, to check what amplifier ic’s they have used.

Kind regards,
Esa

9

Even with the Bodnar usb print I must ground my Heusinkveld Pro pedals from the metal to the - of the print.
This is a must otherwise the pedals going crazy with a direct drive

10

that sounds about normal for analog inputs… I am running Logitech pedals wired to the Simucube and the Analog Pots have sitting noise of about 200 -400 steps out of the range… If this is the case just set the lower deadline to be able the noise… In game calibration will take the new range as full so it doesn’t hurt the final range at all. If it is a jumpy noise while using then that is a different story.

11

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Hi Esa, sorry for the late reply. Here’s the photo of the amp, the ADC used is a AD623.
I’m using the X11 VCC OUT 3.3V. The wire of the loadcell is shieled by the transparent wire.
IMG_3865
IMG_38652737×3438 1.51 MB

I was trying Beano’s grounding instructions, but I find that he’s using the HE pedal set and there’s a wire connection between the OSW case and the Bodnar board gnd pin. If I tried his method, wiring the OSW case and the X11 gnd pin, will I be creating a ground loop? Since I don’t know much about electronics, I’ll post in the forum first. I don’t wanna damage the SimuCUBE. I just burnt one SImuCUBE motherboard not long ago and bought a new one LOL

12

Hi

Tha load cell amp looks to have Analog Devices operational amplifier which has quite good specs (assuming it’s genuine).

How the amp is connected? Is it close to the load cell, or close to simucube?

The wiring to the load cell assumes shielded wire. Is this so?

How long are the wires that are connected to simucube? Those could be twisted for minimal noise protection, however shielded cable would be much better.

Kind regards,
Esa

13

I found this that discusses load cells and has a load cell amplifier board for $9.90
https://learn.sparkfun.com/tutorials/getting-started-with-load-cells