Beachmaster Files

[Olly]

Hello, As you remember, I made this circuit about 2 years ago.
The volume of my circuit is very low, what should I do?
I want to use a small 8 ohm speaker instead of headphones
Thanks

Another way to get more volume is to adjust the Gain trimmer RV5. If this is already trimmed to the max then reducing R39 from 10K down to 4K7 will help, but in this case please adjust RV5 back to center trim first before testing or else Q8 may overheat. It can then be adjusted to suit.

Please check on the temperature of Q8 continually while testing as it will now be subject to greater power dissipation.

Let me know how you get on.

[hamedtaran]

OK, give me a while to investigate and I'll come back to you if I find a solution.

Thank you for your time

[Olly]

OK, give me a while to investigate and I'll come back to you if I find a solution.

[hamedtaran]

The circuit is really designed for a 32 ohm headset, but you could try using a 1K pot for POT5 to see whether that helps.

I used a jumper instead of pot5, but the volume is still very low
thanks

[Olly]

Hello, As you remember, I made this circuit about 2 years ago.
The volume of my circuit is very low, what should I do?
I want to use a small 8 ohm speaker instead of headphones
Thanks

The circuit is really designed for a 32 ohm headset, but you could try using a 1K pot for POT5 to see whether that helps.

[hamedtaran]

Hello, As you remember, I made this circuit about 2 years ago.
The volume of my circuit is very low, what should I do?
I want to use a small 8 ohm speaker instead of headphones
Thanks

[hamedtaran]

Oops! My mistake...
My original design used a 5K pot, but then during testing I found that 20K gave better results so I updated the schematic but inadvertently forgot to update the BOM as well - I do apologise. I will update the BOM when I release the updated doc pack.

Pinpointing is only meant to be used for short periods of time (5 seconds or so at a time). When the pushbutton is pressed it stops updating the SAT level and holds it for a while allowing you to move over the target a lot slower in order to pinpoint the location. Unfortunately this level does leak away so pinpointing can't be used continuously in order to turn the detector into a non-motion type.

I have had a look at your video and it does seem to be working more or less correctly - I can't quite figure out the detection distance of the coin you are using but it looks reasonable. I found that with a 300uH, 20cm, shielded, bundle-wound coil and a TX width of 50uSec I was just about able to detect a 1Euro coin at 12" when the threshold was set low (more clockwise) in a low noise environment.

Kind regards

Hi

[Qiaozhi]

merci bcp

cordialement

Please make your posts in English.
Thanks.

[Made me 2023]

merci bcp

cordialement

[Olly]

Actually, the coil I used for testing was closer to 9", so 22.5 cm diameter not 20 cm.

[Olly]

Hi, I bought RV5 from the bom file, it was 5k there. I will put 20k instead.

[ATTACH]57998[/ATTACH]




Have you seen my test video? What do you think? Of course, the sound of the movie is a little weak, it is better to listen loudly
I connected these two pins together to test the circuit and it is working
see the picture below:

[ATTACH]57999[/ATTACH]

but there is a sound problem,Threshold sound is too much, I hope it will be fixed by replacing rv5
When I cut the connection between these two pins, the circuit no longer senses and produces a continuous sound

Thank you for your time, I will try again tomorrow

Oops! My mistake...
My original design used a 5K pot, but then during testing I found that 20K gave better results so I updated the schematic but inadvertently forgot to update the BOM as well - I do apologise. I will update the BOM when I release the updated doc pack.

Pinpointing is only meant to be used for short periods of time (5 seconds or so at a time). When the pushbutton is pressed it stops updating the SAT level and holds it for a while allowing you to move over the target a lot slower in order to pinpoint the location. Unfortunately this level does leak away so pinpointing can't be used continuously in order to turn the detector into a non-motion type.

I have had a look at your video and it does seem to be working more or less correctly - I can't quite figure out the detection distance of the coin you are using but it looks reasonable. I found that with a 300uH, 20cm, shielded, bundle-wound coil and a TX width of 50uSec I was just about able to detect a 1Euro coin at 12" when the threshold was set low (more clockwise) in a low noise environment.

Kind regards

[hamedtaran]

Hi,

Are you saying that you can't adjust the threshold to a level where the audio output is not audible ?
Ideally RV5 should be a 20K pot, not 5K as too much gain here can lead to instability.
Normally you would start at the 20K setting and increase the gain if required. See section 3.9.2 of the build and test guide.

Hi, I bought RV5 from the bom file, it was 5k there. I will put 20k instead.

If your nominal voltage at TP7 is a little high (Closer to 1.5V would be better) then moving the sample delay a little to the right (POT3) should solve this. See section 3.7.3 of the build and test guide.

Check the configuration of your pinpoint switch, it must be a normally closed pushbutton and in section 3.8.2 of the build and test guide I've shown a work-around if the pushbutton pinout is different (as mine was).

It's strange that you can't tune the audio frequency to below 800Hz, double check the values of R41(150K), RV6(100K) and C29(10nF).

Apart from a bit of fine tuning though it does look as though you've got the detector pretty much working, congratulations!
Kind regards

Have you seen my test video? What do you think? Of course, the sound of the movie is a little weak, it is better to listen loudly
I connected these two pins together to test the circuit and it is working
see the picture below:



but there is a sound problem,Threshold sound is too much, I hope it will be fixed by replacing rv5
When I cut the connection between these two pins, the circuit no longer senses and produces a continuous sound

Thank you for your time, I will try again tomorrow

[Olly]

[ATTACH]57996[/ATTACH]

[ATTACH]57997[/ATTACH]

_As you can see,The voltage range of TP7 is from 2.5v to 4v
_Also, when I disconnect the pinpoint button, I have no any sense
_The sound frequency cannot be set lower than 800 Hz
Regards

If your nominal voltage at TP7 is a little high (Closer to 1.5V would be better) then moving the sample delay a little to the right (POT3) should solve this. See section 3.7.3 of the build and test guide.

Check the configuration of your pinpoint switch, it must be a normally closed pushbutton and in section 3.8.2 of the build and test guide I've shown a work-around if the pushbutton pinout is different (as mine was).

It's strange that you can't tune the audio frequency to below 800Hz, double check the values of R41(150K), RV6(100K) and C29(10nF).

Apart from a bit of fine tuning though it does look as though you've got the detector pretty much working, congratulations!
Kind regards

[Olly]

Hi

http://195.201.124.124:6677/35687519...9_19:27:53.mp4

The sound does not decrease, I set the threshold volume in the lowest mode, do you think the power is good?
I use 5k pot in rv5

Hi,

Are you saying that you can't adjust the threshold to a level where the audio output is not audible ?
Ideally RV5 should be a 20K pot, not 5K as too much gain here can lead to instability.
Normally you would start at the 20K setting and increase the gain if required. See section 3.9.2 of the build and test guide.

[hamedtaran]

_As you can see,The voltage range of TP7 is from 2.5v to 4v
_Also, when I disconnect the pinpoint button, I have no any sense
_The sound frequency cannot be set lower than 800 Hz
Regards