Summing loadcells
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premelec
Senior Member
Welcome to the PICAXE forum. Please give us a bit more info to work with -
Particularly are you speaking of 'raw' load cells without any conditioning amplification?
If not what are the output voltage signals you have to work with?
And to give us a better idea of how to advise - are you experienced with electronics and building equipment or a beginner?
Thanks!
Particularly are you speaking of 'raw' load cells without any conditioning amplification?
If not what are the output voltage signals you have to work with?
And to give us a better idea of how to advise - are you experienced with electronics and building equipment or a beginner?
Thanks!
Firstly, thanks for your reply. Sorry, I am a beginner and have not started well. I have 4 strain gauges (I now realise that may be 1 loadcell) on a set of digital bathroom scales and thought I could "tap in" somewhere downstream of the op amp and process that info with a picaxe microcontroller, or use the raw voltage from the strain gauges and a bridge circuit and op amp.
I did some basic language stuff on Atari 400 (thats a givaway) and a mechanical background with a little electronics understanding. I enjoy a challenge, but do not want to waste members time if it looks beyond my capabilities.
Hope I don't sound like too much of a challenge for you.
Thank you.
I did some basic language stuff on Atari 400 (thats a givaway) and a mechanical background with a little electronics understanding. I enjoy a challenge, but do not want to waste members time if it looks beyond my capabilities.
Hope I don't sound like too much of a challenge for you.
Thank you.
Andrew Cowan
Senior Member
premelec
Senior Member
Back to the question...
The least expensive starter pack is an 08M with download cable and simple circuit board I think. These days the PICAXE 20X2 is one of the best values of function and program capacity and speed for price... The 08M can do a whole lot of things in a very small amount of program and will teach economy of programming - the 20X2 comparatively has huge programing memory as well as more I/O pins and ADC... Download the manuals 1, 2, 3 and read up on the programing commands and so forth and also look at completed projects in this forum and you'll get an idea of what you may want to attempt.
Also search for your 'real' topic -'what should I start with' as there have been previous discussions and opinions...
I'd start simple with the 08M which I still like... and then go big if you feel the need and learned ability... [I started with Sinclair 1000 & VIC 20 computers...
] The PICAXE BASIC language is pretty restricted compared to full blown BASIC - and it does the job... just not like you may be used to with QBASIC etc... so in learning there will be a lot of syntax errors and checking the manuals [and forum]. PICAXE is a great product at a great price.
Note that you can use the editor [free download] to start writing code and use it to check syntax and do trial simulations... and you can select which chip you are working with in the editor options... And you'll need to hone your skills in planning a program and eventually building some hardware - lots of fun! [and frustrations...]. good luck!
The least expensive starter pack is an 08M with download cable and simple circuit board I think. These days the PICAXE 20X2 is one of the best values of function and program capacity and speed for price... The 08M can do a whole lot of things in a very small amount of program and will teach economy of programming - the 20X2 comparatively has huge programing memory as well as more I/O pins and ADC... Download the manuals 1, 2, 3 and read up on the programing commands and so forth and also look at completed projects in this forum and you'll get an idea of what you may want to attempt.
Also search for your 'real' topic -'what should I start with' as there have been previous discussions and opinions...
I'd start simple with the 08M which I still like... and then go big if you feel the need and learned ability... [I started with Sinclair 1000 & VIC 20 computers...
] The PICAXE BASIC language is pretty restricted compared to full blown BASIC - and it does the job... just not like you may be used to with QBASIC etc... so in learning there will be a lot of syntax errors and checking the manuals [and forum]. PICAXE is a great product at a great price.Note that you can use the editor [free download] to start writing code and use it to check syntax and do trial simulations... and you can select which chip you are working with in the editor options... And you'll need to hone your skills in planning a program and eventually building some hardware - lots of fun! [and frustrations...]. good luck!
BeanieBots
Moderator
The PICAXE requires a signal between 0v and 5v (supply rail to be more precise) to give zero to full range readings.
The output from the raw strain gauge is likely to be very small and also sensitive to any additional circuitry you add. Hence, your best bet is to 'tap in' after the bridge processing.
It would be time well spent to draw out as much of the existing circuit as possible and then determine the best point to tap in at. Even then, you might still require some amplification to get a decent range/resolution from an ADC PICAXE input.