Hello George, I am a new member here and cannot PM you yet. However I have been using a friends AP-2 for some time and now looking to purchase or build one for myself. I am working on a very stiff and high mass aluminium rack system and have found the AP-2 / ACH-01 to be an invaluable tool. Will try to add some more posts on here and hopefully persuade the moderators that I am legitimate. Anyone can see that if you check my on Pink Fish Media - Freddiekaberman.
ACH-01 accelerometer seems to be out of stock now.
A good alternative choice seems to be the 805M1-0200 sensor from Measurement Specialties.
I am thinking to modify the AP-2 amplifier to accept this sensor.
I was wondering if there is enough interesting by others for this modification.
Your response is welcome.
A good alternative choice seems to be the 805M1-0200 sensor from Measurement Specialties.
I am thinking to modify the AP-2 amplifier to accept this sensor.
I was wondering if there is enough interesting by others for this modification.
Your response is welcome.
From the 805M1 Datasheet: Non-Linearity (%FSO) ±1
A maybe naive conclusion: Does this mean that accuracy is 2% thoughout the whole range from 0 to 20G? If so, then this accuracy might be perfectly ok for assessing strong earthquakes, and for woofers below 100Hz (or so), where a woofer's THD might reach typical values of some 5% ... 30%? A decent speaker instead may typically have a THD well below 2% in the frequency range above 100Hz or so. So this sensor seems quite useless to me for speaker testing or for servo feedback application. Or am I wrong?
A maybe naive conclusion: Does this mean that accuracy is 2% thoughout the whole range from 0 to 20G? If so, then this accuracy might be perfectly ok for assessing strong earthquakes, and for woofers below 100Hz (or so), where a woofer's THD might reach typical values of some 5% ... 30%? A decent speaker instead may typically have a THD well below 2% in the frequency range above 100Hz or so. So this sensor seems quite useless to me for speaker testing or for servo feedback application. Or am I wrong?
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You are right. Sorry for my sloppy formulation. Ok, then. Let's try once again, but in a different way: How precise can any measurements (or servo application) best-case be expected with the specs published by the manufacturer?
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I'd say the noise figure given in the datasheet provides the limit for precision of the sensor readout.
If you want to attach the accelerometer to the speaker's cone another important issue you have to consider is the weight of the accelerometer sensor.
The ACH-01 has a weight of about 3 gram while the 805M1 a weight of 5 gram.
To keep the effect of the added accelerometer at a low level, the weight of the cone should be at least 10 times.
This means the speaker will be a woofer.
So the non-linearity of the sensor will not be a very serious issue.
But the main use of the accelerometer sensor with the AP-2 amplifier is the investigation of vibration issues for enclosures of loudspeakers, or turntables etc.
regards
George
The ACH-01 has a weight of about 3 gram while the 805M1 a weight of 5 gram.
To keep the effect of the added accelerometer at a low level, the weight of the cone should be at least 10 times.
This means the speaker will be a woofer.
So the non-linearity of the sensor will not be a very serious issue.
But the main use of the accelerometer sensor with the AP-2 amplifier is the investigation of vibration issues for enclosures of loudspeakers, or turntables etc.
regards
George
I have available a few sets of Front Panels and PCBs for the AP-2 Accelerometer amplifier.
If you are interested send me a message.
If you are interested send me a message.
Hi to all, I finally found the time to construct my AP-2. This was my first serious DIY project in terms of PCB assembly. I have almost zero knowledge of electronics and have only recently developed my soldering skills to a reasonable level, so this has been a learning curve to say the least.
The instructions, layout diagrams and photos provided are very clear and George has been very helpful with a couple of small troubleshooting issues. The unit is working well now and I can get on with my aluminum rack project....
The instructions, layout diagrams and photos provided are very clear and George has been very helpful with a couple of small troubleshooting issues. The unit is working well now and I can get on with my aluminum rack project....
For quite some time now, the ACH-01 accelerometer has not been easy to find, although according to its manufacturer it has not been discontinued.
I thought, it is time to move on to something new.
As I have already mentioned, I chose the 805M1-200 accelerometer and I just concluded the modifications and testing on the AP-2 amplifier for this type of accelerometer. The modifications are very simple and easy to do on the existing PCB.
I have in stock some PCBs and Front Panels, as shown in post #81 for the Accelerometer amplifier.
I will also provide detailed instructions for building the amplifier and connecting the 805M1-200 sensor.
Anyone interested, please send me a message.
I thought, it is time to move on to something new.
As I have already mentioned, I chose the 805M1-200 accelerometer and I just concluded the modifications and testing on the AP-2 amplifier for this type of accelerometer. The modifications are very simple and easy to do on the existing PCB.
I have in stock some PCBs and Front Panels, as shown in post #81 for the Accelerometer amplifier.
I will also provide detailed instructions for building the amplifier and connecting the 805M1-200 sensor.
Anyone interested, please send me a message.
After further testing, the 805M1 has proven to work well for vibration measurements.
I still have PCBs and front panels available for anyone interested in building the amplifier.
I still have PCBs and front panels available for anyone interested in building the amplifier.