Pressure sensing system for a planter
A pressure sensing system for a seeding machine such as a planter to measure the down force on a planter row unit uses a wireless pressure sensor embedded in a load carrying wheel of the row unit. In a preferred embodiment, the pressure sensor is a passive piezoelectric pressure sensor that is a transmitter only, transmitting both pressure and RFID the information that identifies the particular sensor. Multiple sensors may be employed in each wheel and sensors may be employed in more than one wheel of the row unit, such as the gauge wheels on opposite sides of the trench opening disks. The sensors may be made of a PVDF, a known piezoelectric material. A wireless receiver is located on the planter frame or could be located elsewhere to receive the signals from the pressure sensor. A controller determines from the signal, any change in down force and commands the change to a down force generator on the row unit.
1. A row unit for a seeding machine comprising:
means forming a seed trench in the soil, means for delivering seed to the seed trench, and means for covering the seed in the seed trench;
a ground engaging and load carrying wheel; and
a wireless pressure sensor directly attached to said wheel generating an output signal indicative of the pressure between the wheel and the ground.
2. The row unit as specified in claim 1 wherein the signal includes a sensor identifier.
3. The row unit as specified in claim 1 wherein the ground engaging wheel is a gauge wheel to control the depth of the seed trench.
4. The row unit as specified in claim 3 having multiple said sensors in the gauge wheel.
5. The row unit as specified in claim 3 having a pair of said gauge wheels on opposite sides of the means forming a seed trench and at least one sensor in each said gauge wheel.
6. The row unit as specified in claim 1 wherein the ground engaging wheel is a trench closing wheel.
7. The row unit as specified in claim 1 wherein the sensor is a piezoelectric pressure sensor.
8. The row unit as specified in claim 7 wherein the piezoelectric sensor is a transmitter only.
9. The row unit as specified in claim 7 wherein the piezoelectric sensor is made of PVDF.