I would like to interface a geophone to the picaxe. I have tried using a single stage transistor amplifier feeding the ADC input of picaxe and it worked well enough, would sense a tap on the table reliably. I want to try using an OPAmp circuit and am asking for suggestions on how best to interface to picaxe. Attached is the circuit i built, sorry for the crude drawing,
So far I've attached the output to an oscilloscope, a 1980s tektronix without computer interface. The geophone is very sensitive and will detect footsteps on a concrete floor. I have it AC coupled and it shows volt or more peak to peak on the scope by just dropping a screwdriver nearby.
The geophone is a surplus unit and it looks like the sparkfun one,
http://www.sparkfun.com/products/11744
The signal from the op amp is pretty brief so I'm not sure what would be the best way to interface to the picaxe. I have the other half of the op amp available for a pulse stretcher circuit then I can just use a digital input of the picaxe or would it be better to make many ADC readings. Either way, I'm thinking I'll need to set the frequency of the picaxe as high as possible. I have an assortment of picaxe chips available, I can use whatever works best.
The other possibility, if picaxe isn't fast enough to capture the data I can use a raw pic chip as an intermediary.
I don't have a specific use planned just experimenting.
Thank you and a Happy New Year to all.
So far I've attached the output to an oscilloscope, a 1980s tektronix without computer interface. The geophone is very sensitive and will detect footsteps on a concrete floor. I have it AC coupled and it shows volt or more peak to peak on the scope by just dropping a screwdriver nearby.
The geophone is a surplus unit and it looks like the sparkfun one,
http://www.sparkfun.com/products/11744
The signal from the op amp is pretty brief so I'm not sure what would be the best way to interface to the picaxe. I have the other half of the op amp available for a pulse stretcher circuit then I can just use a digital input of the picaxe or would it be better to make many ADC readings. Either way, I'm thinking I'll need to set the frequency of the picaxe as high as possible. I have an assortment of picaxe chips available, I can use whatever works best.
The other possibility, if picaxe isn't fast enough to capture the data I can use a raw pic chip as an intermediary.
I don't have a specific use planned just experimenting.
Thank you and a Happy New Year to all.