Tweet
All
I have been experimenting with driving a 555 monostable with positive going pulses from the 12f683 using Altra's code, with very good results, (using the hex from post #43)
The idea is to drive a IRF740 fet from the 555, and use the two sample pulses from the12f683, altra's code uses a pot to externally change the sample delay timing. The samples are set at about 15uS, with 200uS spread.
The code has set values of TX and sample pulse width, you can alter the pulse width but requires the 12f683 to be reprogrammed.
By driving a 555 monostable with the 12f683
You can independently set the TX pulse width from about 20uS to 200uS,
and independently set the 1st sample delay from zero to about 200uS (depending on 555 TX pulse width)
by using just two pots.
actually with respect to the tx pulse, you can set the 1st sample delay to minus 100uS that's no good to us, but you can do it.
The only catch is if you have a wide 555 TX pulse, say 200uS, this reduces the 1st sample pulse delay time choice,
with wide 555 Tx pulse width, the 1st sample delay can only be set to a maximum of about 120uS
this is because wide TX pulses of the 555 use up some of the sample pulse delay timing.
this can be altered in the code if required .
As an example you can set the TX pulse width to 50uS for gold, or say 100uS for coins, or say 200uS for relics
while setting the sample delay to suit your coil and target type, etc, etc, from two pots.
I will try and take some scope pictures and post
6666
I have been experimenting with driving a 555 monostable with positive going pulses from the 12f683 using Altra's code, with very good results, (using the hex from post #43)
The idea is to drive a IRF740 fet from the 555, and use the two sample pulses from the12f683, altra's code uses a pot to externally change the sample delay timing. The samples are set at about 15uS, with 200uS spread.
The code has set values of TX and sample pulse width, you can alter the pulse width but requires the 12f683 to be reprogrammed.
By driving a 555 monostable with the 12f683
You can independently set the TX pulse width from about 20uS to 200uS,
and independently set the 1st sample delay from zero to about 200uS (depending on 555 TX pulse width)
by using just two pots.
actually with respect to the tx pulse, you can set the 1st sample delay to minus 100uS that's no good to us, but you can do it.
The only catch is if you have a wide 555 TX pulse, say 200uS, this reduces the 1st sample pulse delay time choice,
with wide 555 Tx pulse width, the 1st sample delay can only be set to a maximum of about 120uS
this is because wide TX pulses of the 555 use up some of the sample pulse delay timing.
this can be altered in the code if required .
As an example you can set the TX pulse width to 50uS for gold, or say 100uS for coins, or say 200uS for relics
while setting the sample delay to suit your coil and target type, etc, etc, from two pots.
I will try and take some scope pictures and post
6666
Comment