[SS2S-Main] Re: Digital scale load-cell design / instrumentation

  • From: "Lampe, Mattias SLC CT PEK" <mattias.lampe@xxxxxxxxxxx>
  • To: "sugarshot@xxxxxxxxxxxxx" <sugarshot@xxxxxxxxxxxxx>
  • Date: Sun, 19 Jan 2014 11:32:21 +0800

The load cell itself has an analog output, and there are a number of integrated 
circuits or modules to amplify and A/D convert the signal. Speed is typically 
between 10-100 samples per second, which should be sufficient. You are right 
that bathroom scales are slow, but that's not due to the load cell itself but 
rather caused by the signal processing (averaging) in the display unit. You are 
also right that a microcontroller is sufficient to collect the load cell data. 
The PC is merely for display/storage/post processing.



Mattias





From: sugarshot-bounce@xxxxxxxxxxxxx [mailto:sugarshot-bounce@xxxxxxxxxxxxx] On 
Behalf Of m bindhammer
Sent: Saturday, January 18, 2014 10:48 PM
To: sugarshot@xxxxxxxxxxxxx
Subject: [SS2S-Main] Re: Digital scale load-cell design / instrumentation



Is the communication protocol  of a kitchen/bathroom scale load cell analog or 
digital? 2000N should be the max. what a bathroom scale could measure (approx 
200 kg). Sampling rate would be interesting and important too. Most bathroom 
scales are very slow. However, it is pretty easy to design according 
electronics/data logger for it. You could do this embedded with a micro 
controller and SD card, you don't need a PC.

Markus



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From: vicente_alvero_14@xxxxxxxxxxx<mailto:vicente_alvero_14@xxxxxxxxxxx>
To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx>
Subject: [SS2S-Main] Re: Digital scale load-cell design / instrumentation
Date: Sat, 18 Jan 2014 13:41:23 +0100

maybe Richard, can design and build a load cell based on websites, and another 
member of the electronic

  _____

From: vicente_alvero_14@xxxxxxxxxxx<mailto:vicente_alvero_14@xxxxxxxxxxx>
To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx>
Subject: [SS2S-Main] Re: Digital scale load-cell design / instrumentation
Date: Sat, 18 Jan 2014 13:36:17 +0100

I have not just knowledge of electronics, so this work should be made between 
several members

  _____

To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx>
Subject: [SS2S-Main] Re: Digital scale load-cell design / instrumentation
From: monsieurboo@xxxxxxx<mailto:monsieurboo@xxxxxxx>
Date: Sat, 18 Jan 2014 07:11:34 -0500

It's been a few years since discussion of these digital-scale load cells was 
ricocheting around the rocketry forums.  Naturally, I started by checking 
Nakka's site -- he's got a very cool "built from scratch" strain-gage design 
but I couldn't find one there that starts with a digital scale.  But here's a 
good starting point for what you're talking about.  This one hooks up to a PC 
with a "COM port" USB interface, and the author hand-rolled the electronics.

http://www.steeman.be/?p=192

Enjoy!

Mark L.
DC



-----Original Message-----
From: vicente Alvero Zambrano 
<vicente_alvero_14@xxxxxxxxxxx<mailto:vicente_alvero_14@xxxxxxxxxxx>>
To: sugarshot <sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx>>
Sent: Sat, Jan 18, 2014 3:54 am
Subject: [SS2S-Main] Re: Interesting Motor-Design Documents

Hi Mattias,


It would be great if you could you do this. I think the maximum thrust is 
2000N, but better than Richard confirm it.



Vicente Alvero

  _____

From: mattias.lampe@xxxxxxxxxxx<mailto:mattias.lampe@xxxxxxxxxxx>
To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx>
Date: Sat, 18 Jan 2014 10:37:27 +0800
Subject: [SS2S-Main] Re: Interesting Motor-Design Documents

If you want to go even cheaper, load cells can be scavenged from cheap digital 
kitchen/bathroom scales. It's not too difficult to hook them up to a computer. 
I can probably help with the electronics, but not so much with the mechanical 
part.



What would be the maximum force to be measured?



Mattias



From: sugarshot-bounce@xxxxxxxxxxxxx<mailto:sugarshot-bounce@xxxxxxxxxxxxx> 
[mailto:sugarshot-bounce@xxxxxxxxxxxxx<mailto:sugarshot-bounce@xxxxxxxxxxxxx?>] 
On Behalf Of vicente Alvero Zambrano
Sent: Friday, January 17, 2014 12:47 AM
To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx>
Subject: [SS2S-Main] Re: Interesting Motor-Design Documents



Instruments would be a gauge and load cell, right? but this must be commercial. 
some sets is "cheap". with relative to a support, I think we would have 
problems. that would be cheap.
http://aeroconsystems.com/cart/load-cells/

maybe we can also use the pressure gauge and load cell minisshot rocket.

  _____

Date: Thu, 16 Jan 2014 10:30:00 -0600
Subject: [SS2S-Main] Re: Interesting Motor-Design Documents
From: richard.nakka@xxxxxxxxx<mailto:richard.nakka@xxxxxxxxx>
To: sugarshot@xxxxxxxxxxxxx<mailto:sugarshot@xxxxxxxxxxxxx>

To design/build the instruments to measure motor thrust and chamber pressure. 
We would have to do this on a "tight" budget.



R.

On Thu, Jan 16, 2014 at 10:18 AM, vicente Alvero Zambrano 
<vicente_alvero_14@xxxxxxxxxxx<mailto:vicente_alvero_14@xxxxxxxxxxx>> wrote:


What kind of help with the instrumentation?

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