jlehman
Newbie level 3
I am trying to adapt an app note AN2548 (Ultrasonic Range Finder with a tiny817), for this project and need someone I can ask a few questions.
1) The product will use 3 weather proof ultrasonic sensors that have been picked by the customer.
2) The product needs to detect a range of at least 18 ft and it would be good if I could go down to 2 ft without any gain changes.
3) The product needs will sample at a 15Hz rate of measurement. The sensors will not overlap so they can be driven simultaneously.
I have attached 1 page of the schematic implemented on the first turn of boards. The initial detection was not sensitive to get even a few feet with the speced sensors
So I have tried a 25V supply and now have a excitation voltage of around 55V. This does concern me a bit from a safety perspective, but this is commercial not a customer product.
Questions:
1) Am I on the right track? Is there a better circuit?
2) As I push the excitation voltage higher I am not sure how to determine if I am violating the specs of the transistor in the front of the input chain.
3) With the current changes, detailed in the schematic, I am up to 10ft but have a ways to go, so need ideas how to get another 8ft
Thanks in advance for any help
1) The product will use 3 weather proof ultrasonic sensors that have been picked by the customer.
2) The product needs to detect a range of at least 18 ft and it would be good if I could go down to 2 ft without any gain changes.
3) The product needs will sample at a 15Hz rate of measurement. The sensors will not overlap so they can be driven simultaneously.
I have attached 1 page of the schematic implemented on the first turn of boards. The initial detection was not sensitive to get even a few feet with the speced sensors
So I have tried a 25V supply and now have a excitation voltage of around 55V. This does concern me a bit from a safety perspective, but this is commercial not a customer product.
Questions:
1) Am I on the right track? Is there a better circuit?
2) As I push the excitation voltage higher I am not sure how to determine if I am violating the specs of the transistor in the front of the input chain.
3) With the current changes, detailed in the schematic, I am up to 10ft but have a ways to go, so need ideas how to get another 8ft
Thanks in advance for any help