GB2132395A

GB2132395A - A monitor suitable for use with a seed planter

Info

Publication number: GB2132395A
Application number: GB08332163A
Authority: GB
Inventors: Herbert Arnold; Tibor Kenedi
Original assignee: FEDMECH HOLDINGS Ltd
Current assignee: FEDMECH HOLDINGS Ltd
Priority date: 1982-12-06
Filing date: 1983-12-01
Publication date: 1984-07-04
Also published as: GB8332163D0; ZW26583A1; GB2132395B

Abstract

This invention concerns a monitor suitable for use with a seed planter. A conventional seed plate having a plurality of apertures is provided for the planter to feed seeds to a discharge means. A first sensor 6, 8 adapted to establish the desired seed population, senses the slots 204a in the seed plate. A second sensor is associated with the discharge means to establish the actual seed population discharged by the planter. An alarm may be activated when the desired and actual seed populations do not substantially correspond. In this manner, the operator will be alerted when seeds are not ideally discharged by the planter. <IMAGE>

Description

SPECIFICATION A monitor suitable for use with a seed planter This invention concerns a monitor suitable for use with a seed planter of the conventional kind, which monitor is capable of establishing whether the desired plant population is being achieved during operation of the planter.

The term desired or theoretical plant population when applied to conventional seed planters, means that population which should be achieved if the planter functions optimally. In the cultivation of lands, optimal growth and maximization of crop yield is an important consideration to the farmer. If seeds are dropped from a planter in a manner which is not optimal and which does not achieve the theoretical population, crop yield maximization will be frustrated. If, for example, two seeds are dropped in the same place by the planter and both seeds germinate, stunted plants may result. Also, if the planter does not drop a seed where it ought to, the optimal interval between plants will not be achieved, resulting in the frustration of yield maximization.

It is an object of this invention to provide a monitor for a seed planter which is capable of comparing the theoretical or desired plant population with the actual plant population.

According to the invention a monitor suitable for use with a seed planter which discharges a seed population during travel thereof comprises first means adapted to establish the desired seed population to be discharged from the seed planter during a predetermined travel thereof, second means adapted to establish the actual seed population discharged by the seed planter during the same travel thereof and means for comparing the desired and actual seed populations to establish any positive or negative imbalance therebetween.

Further according to the invention, the first means comprises first sensor means associated with a seed plate of the planter and the second means comprises second sensor means associated with seed discharge means of the planter, signal means being provided adapted to be activated when the desired and actual populations do not substantially correspond.

Further according to the invention the seed plate defines seed receiving zones in the form of pockets, apertures or the like and which is adapted to rotate to feed the seed to a discharge means; the first sensor comprising first transducer means adapted to count the seed receiving zones during rotation of the seed plate.

Further according to the invention the first transducer means comprises a light responsive tranducer such as a photo-transistor and a light source arranged such that the passage of a seed receiving zone will cause the light source to trigger the transducer.

Further according to the invention the seed receiving zones are apertures and the light responsive transducer and light source are arranged on opposite sides of the seed plate so that the transducer will sense an aperture when such aperture is in register with the light source and transducer.

Further according to the invention the monitor includes a first counter which is adapted to receive a signal from the first transducer means whenever a seed receiving zone is detected.

Further according to the invention the first transducer means is associated with a comparator and a variable resistor set at a predetermined threshold resistance, which signals the first counter.

Further according to the invention the monitoring for imbalance is effected repeatedly and consecutively during travel of the seed planter.

Further according to the invention the seed planter includes a seed plate having seed receiving zones in the form of pockets, apertures or the like and which is adapted to rotate to feed seed to discharge means, the desired seed population bering established by counting the seed receiving zones on the seed plate during rotation thereof.

Further according to the invention the seed planter includes discharge means through which seeds discharged by the seed planter pass to the ground, the actual seed population being established by counting the number of seeds passing through the discharge means.

With this arrangement, applicant believes the difficulties presently associated with automatic seed planters will at least be reduced.

Further according to the invention the second sensor comprises second transducer means which is adapted to be actuated by the passage of substantially each seed which passes through the discharge means.

Further according to the invention the second transducer means comprises a light dependent resistor, a photo transistor, capacitor sensor, trigger or the like.

Further according to the invention the monitor includes a second counter which is adapted to receive a signal from the second sensor whenever the passage of a seed through the discharge means is detected.

Further according to the invention signals are passed to the first counter and the second counter via logic circuit gates.

Further according to the invention the signal means comprises an audio and/or visual alarm.

The invention will now be described by way of illustration only with reference to a presently preferred embodiment of a seed planter monitor shown in the accompanying drawings and in which: Figure 1 is an exploded view of a seed planting unit carrying a monitor according to the invention; Figure 2 is a typical circuit diagram of the plate sensor signal conditioning circuit; Figure 3a is a typical circuit diagram of the seed sensor signal conditioning circuit; Figure 3b is a circuit diagram of a seed sensor used in the circuit of Figure 3a; Figure 4a is a circuit diagram of a logic circuit associated with the plate sensor circuit; Figure 4b is a typical circuit diagram of a monostable multivibrator which forms part of the circuit shown in Figure 4a;; Figure 4c is a circuit diagram of the logic circuit associated with the output of the circuit of Figure 4b and with the seed sensor circuit; and Figure 5 is a typical circuit diagram of a buzzer associated with alarms of the monitor.

A conventional planter (not shown) includes a pneumatic seed planting unit shown in exploded form in Figure 1. The unit comprises a housing made of a first part 200 and a second part 201.

The second part has holes 202 adapted to receive studs 203 provided on the first part 200 to permit the two parts to be clamped together. A seed plate 204 having radial slots 2d4a is interposed between the first and second parts of the housing.

The first part carries an inlet 205 for seeds and a backing plate 206 having an air slot 206a therein.

An air suction connection 208 is provided to create a state of reduced pressure behind the backing plate 206. The seed plate 204 of the seed planting unit seats on the backing plate 206 and is driven about its axis from a ground engaging wheel of the planter in conventional manner.

In use of the seed planting unit, seeds are fed through the inlet 205 which gravitate to the front side 204b of the seed plate through central inlets 209. The intersection of a slot 204a in the seed plate 204 with the air slots 206a in the backing plate 206 creates a small opening which attracts a seed by virtue of the reduced air pressure created behind the plate 206. The seed, which is too large to pass through the slot 204a, is carried along by the seed plate 204 as it rotates until it reaches the end 206b of the air slot, whereupon it is released, through lack of suction to hold it, and falls under the action of gravity down a passage 210 in the second part 201 of the housing and thence through an outlet 211 in the second part.

A cover plate 212 is fitted to the second part 201 to complete the construction of the outlet 21 1.

The seed plate 204 can be exchanged for different seed plates with different numbers of slots, depending on the seed population required to be discharged. A depression is preferably formed in the seed plate on its front side 204b along a length of each slot 204a so that it will hold a seed better.

A first sensor is provided to establish the desired seed population which the particular seed plate should discharge during a given travel of the planter under normal operating conditions. The sensor is contained in a plate sensor conditioning circuit 4 shown in Figure 2. It comprises a phototransistor 6 located on the second part 201 of the planting unit which generates an electric current when affected by light and a light source in the form of a constant current light emitting diode 8 located on the first part 200 of the planting unit and aligned with the photo-transistor 6.

A 68 ohm resistor 7 is connected on the input side of the photo-transistor 6.

Thus, the photo-transistor 6 generates a pulse whenever a slot 204a in the rotating seed plate 204 is in register with the photo-transistor 6 and light source 8. The desired seed population will be established with the aid of this sinusoidal pulse which is passed across lines including a 470 ohm resistor 9 and a 0--5 K ohm variable resistor 10 to an amplifier 11 in the form of a comparator.

The amplifier 11 is connected to a 100 K ohm resistor 12 and conditions the signal from the photo-transistor 6 into a TTL compatible square wave form.

A second sensor is provided to establish the actual seed population discharged through the outlet 211 of the seed planting unit. The second sensor is contained in a seed sensor conditioning circuit 5 shown in Figure 3a and is in the form of a light sensitive device 13 which generates a signal which is passed through 1 K ohm variable resistor 14 to an amplifier 15, the output of which is passed to a comparator 1 6 associated with a O- 5 K ohm variable resistor 1 7. The output from comparator 16 is similarly in a TTL compatible square wave form. The seed sensor circuit 5 also includes a 1 K ohm resistor 18, a 10 K ohm resistor 19, a 470 ohm resistor 20 and a 100 K ohm resistor 21.

The light sensitive device 13 of the circuit 5 is more fully illustrated in Figure 3b. It is of the conventional optical switch kind and includes a white light source in the form of an incandescent lamp 100 located on one side of the outlet 211 of the planting unit and a light dependent resistor 102 located on the other side of the outlet. The lamp 100 and the light dependent resistor 102 is each housed in a body of polymeric plastics material 213,214 respectively.

The light 100 and resistor 102 are connected across lines 104 and 106 of the sensor circuit in lines 108 and 110 respectively. A 10 K ohm resistor 112 is provided in line 110 and line 114 includes a 1,5 micro Farad polyester capacitor 11 6 and a 0.47 micro Farad polyester capacitor 11 8 in parallel connected to line 110 between the light dependent resistor 102 and the resistor 112.

The other end of line 114 is connected to a switch in the form of a transistor 120 and a line 122 including a 270K ohm resistor 124 is connected across the lines 104 and 114 between the capacitors 116, 118 and the transistor 120. A second switch in the form of a transistor 126 is connected to the transistor 120 and a 1 OK ohm resistor 128 is provided in a line 1 30 across lines 104 and 1 32 between the transistors 120 and 126. A 0,01 micro Farad capacitor 134 is connected between line 130 and the transistor 126.

In use, a seed travelling under gravity through the outlet 211 of the planting unit will interrupt the beam of light from lamp 1 00. The interruption will affect the light dependent resistor 1 O2 and a signal will be generated with the aid of which the number of seeds passing through the discharge chute will be established.

The components of the logic circuits shown in Figures 4(a) and 4(b) will be apparent from the description of their operation which follows.

The pulse from the plate sensor circuit 4 is passed through gates 22 and 23 to the input of an 8-bit counter 24. While input signals are received by the counter, the counter displays the number of input signals received until the present on its binary outputs marked 20 to 27.

When the number of input pulses received by the counter is 50, then output lines B, E and F are logic highs.

(21+24+25=2+16+32=50).

The output from NAND gate 2'5 is then a logic low. The output from NAND gate 25 will stay a logic low until the number of input pulses received bathe counter exceeds 51.

If the counter is reset before the count reaches 52, the output from logic gate 25 is a logic high for input pulses 0 until the 50th pulse or 50 input pulses to the counter. The output of logic gate 25 on line 31 will be referred to as the seed count enable signal or SCE.

The SCE line 31 is fed into a dual NAND gate 26 which acts as an inverter. When SCE line 31 is high, the output from gate 26 is low and vice versa. On reaching the count of 51, SCE on line 31 is low and the output from gate 26 is high.

Also, line A(20) becomes high, i.e.

(20+21+24+25=1 +2+16+32=51).

The three inputs to a NAND gate 27 are therefore high, switching the output from gate 27 to a logic low. The output from logic gate 27 will be referred to as the plate count enable signal PCE) on line 32.

When the output from gate 27 is low, the output from a dual input NAND gate 28 is high as that gate acts as an inverter. The output from gate 28 will be referred to as the clear counter enable signal (CCE) on line 33. When CCE on line 33 is high, a pulse on the plate sensor signal line will cause a pulse output from a dual input NAND gate 29. This pulse acts as a trigger for a monostable multi-vibrator 30.

As may be seen from Figure 4b of the drawings, the monostable multi-vibrator 30 comprises an integrated circuit indicated generally by the numeral 34. The monostable multi-vibrator 30 includes, in addition, a 0,01 micro Farad capacitor 35, a 4,7 micro Farad capacitor 36 and a 300 ohm resistor 37.

On receiving a trigger input, the monostable multi-vibrator 30.generates a square clear pulse of predetermined duration on the clear counter signal line (CC) marked 38. This CC signal on line 38 resets the 8-bit counter to zero. It can be shown that the plate sensor logic circuit of Figure 4a achieves the following: A clear counter signal is generated on the CC line 38, resetting it on the 52nd plate sensor pulse.

A logic high is generated on the SCE line 31 until the 50th plate sensor pulse.

A logic high is generated on the PCE line 32 until the 51st plate sensor pulse.

Dual input NAND gate 22 feeds the plate sensor signal pulses into NAND gate 23 while the PCE line 32 is a logic high. It thus allows 51 successive pulses into the counter. NAND gate 23 acts as an inverter/buffer for the counter.

Referring now particularly to Figure 4c of the drawings, NAND gates 39 and 40 respectively combine to act as a buffer on the SCE line 31.

While SCE on line 31 is a logic high, a NAND gate 41 is enabled and seed sensor pulse signals are fed through a NAND gate 42 to the 8-bit counter 43. Since SCE on line 31 is a logic high for 50 plate pulses, the seed counter 43 counts the number of seeds passing through the outlet of the planting unit for a period during which 50 seeds should have been passed. The logic circuit connected to the counter outputs evaluates the number of seeds dropped into the ground and compares it with the theoretical number that should have occurred, the theoretical number being established by the plate sensor logic circuit of Figure 4(a).

The logic system is adapted to: a) Provide a "doubles" alarm (over-planting alarm) condition when the number of seeds detected in the seed chute exceed the desired number of seeds as represented by the number of plate sensor pulses by 10% or more.

b) Provide a "skips" alarm (under-pianting alarm) condition when the number of seeds detected in the seed chute is 6% to 36% below the desired number of seeds as represented by the number of plate sensor pulses.

c) Provide a "blockage" alarm condition when the number of seeds detected in the seed chute is 38% to 100% below the desired number of seeds as represented by the number of plate sensor pulses.

As described with reference to the plate sensor logic, one measurement period consists of 50 plate sensor pulses. A 10% or greater excess would represent 55 seeds or more being detected in the seed chute. A "doubles" alarm condition occurs whenever the counter 43 output indicates a number greater than 54. This can be verified under the output of OR gate 44.

Similarly, if the number of seeds counted during the measurement period is below 48 but above 31, a "skips" alarm condition exists since these numbers represent a short-fall of between 6% and 36% relative to the desired 50 seeds. This can similarly be verified under the output of AND gate 45.

A blockage alarm condition exists only if the number of seeds detected during the measurement period is iess than 32 seeds. This can be shown by the output of AND gate 46.

Dual AND gates 48, 49 and 50 ensure that the alarm condition outputs from gates 44, 45 and 46 respectively are scanned only at the end of the measurement period. The end of the measurement period is signalled by a logic low of the SCE lines 30. Inverter 51 translates this into a logic high on the inputs to gates 48, 49 and 50.

The outputs from gates 44, 45 and 46 are thus read only at the end of the measurement period.

During the measurement period the outputs from gates 44, 45 and 46 are meaningless.

A blockage alarm condition is considered as a serious situation and the operator is warned immediately. The output from AND gate 50 is fed into an RS flip-flop comprised of the associated NOR gates 52 and 53. Should the output from AND gate 50 indicate a blockage alarm condition at the end of a measuring period, the output from NOR gate 53 will become high. This will in turn switch on transistor 54 which provides power to the constant current light emitting diode 55 on the front panel of the monitor.

The logic high on the NOR gate 53 output also sets the alarm buzzer line 65 high which activates an audible alarm 56, which may be a piezo buzzer, via a transistor switch 57 as shown particularly in Figure 5 of the drawings.

"Doubles" and "skips" alarms are not considered to be as serious unless they occur consistently. Therefore, these alarm conditions are counted by 4-bit binary counters. Consider, for example, the doubles alarm.

If a "doubles" alarm exists at the end of a measurement period, the output from AND gate 48 will momentarily go high, followed by a low as AND gate 48 is de-activated at the beginning of the next measurement period. This pulse is fed into the asynchronous 4-bit binary counter 58.

When the counter reaches the figure of 5 representing 5 doubles alarm conditions, the output from the dual AND gate 59 goes high. This in turn sets the output of the RS flip-fiop comprised of the NOR gates 60 and 61. When the output from NOR gate 61 goes high (RS flip-flop sets) transistor 63 is switched on and power is provided to the constant current light emitting diode 64. The alarm buzzer line 65 is also set high and the audible buzzer 56 is activated by the transistor switch 57.

Doubles alarms are allowed to occur randomly without setting off the alarms. Warning is only given should 5 successive doubles alarms occur, i.e. in successive measurement periods. For this reason, the counter 58 is cleared and reset to zero if a doubles alarm does not occur at the end of a measuring period. This is achieved by an inverter 66 which inverts the doubles alarm output from AND gate 48. This inverted signal will be high should no doubles alarm occur at the end of the measurement period. AND gate 67 is then enabled by the CCE line 33 which is high while waiting for counter to be cleared.

The operator is thus warned only of a consistent overplanting error. The level of consistency is readily adjusted by changing the inputs to AND gate 59 to represent a higher or lower number of successive alarms required to set the alarm.

An identical circuit on the "skip" alarm section of the circuit (gates 68, 69, 70, 71 and 72 and counter 73) ehsurns that the skips alarm is activated only when 5 successive skip conditions occur.

Diodes 74, 75, 76, 77, 78 and 79 are required to prevent oscillation of the RS flip-flop outputs while diodes 80, 81 and 82 isolate the CC on line 38, CCE on line 33 and alarm reset lines from each other, unless a front panel reset button 84 is activated.

OR gate 83 is provided to ensure that the inputs to NOR gates 61,72 and 53 are not floating and remain at a logic low unless the front panel reset button 84 is activated.

To the operator, a blockage alarm may, for example, mean a blocked seed inlet chute, an empty seed bin, a broken drive chain to the planting unit, a damaged seed sensor or damaged wiring.

A "skips" alarm may, for example, indicate insufficient vacuum behind the backing plate 206 of the planting unit, a seed plate 204 having slots 202a which are too narrow, a backing plate 206 having too narrow a slot 206a, or, excessive ground speed of the planter.

A "doubles" alarm may, for example, indicate excessive vacuum behind the backing plate 206, a seed plate having slots 204a which are too wide, a backing plate having a slot 206a which is too wide, or, a ground speed of the planter which is too slow.

Only one channel for a seed planter has been illustrated in Figures 4a and 4b of the drawings.

Applicant intends however, that the monitor will be capable of being applied to a number of seed planting units in an automatic planter. Thus, the lines marked 85, 86 and 87 on Figure 4b would be connected to the other planting units in a single automatic seed line 65.

Applicant believes that, with the arrangement of the present invention, automatic planting may more effectively be performed. The planter operator will be informed when an imbalance between actual.and theoretical seed populations manifest itself.

Although the invention has been described and illustrated with reference to a presently preferred embodiment, it will be apparent to those skilled in the art that many variations and modifications are possible without departing from the scope of the above disclosure. Thus, for example, although the invention has been described and illustrated with reference to a light dependant resistor as the means of establishing the number of seeds which pass down the discharge chute, it would be possible to use alternative arrangements such as a mechanical device in the form of a pin or the like adapted to be deflected by the seeds when they pass through the discharge chute.

The monitor according to the invention has been described as used on a pneumatic planting unit. It could of course equally well be used on the more commonly known gravitational planting unit employing a horizontal seed plate having holes therein through which the seeds are discharged to a discharge chute.

Claims

1. A monitor suitable for use with a seed planter which discharges a seed population during travel thereof comprises first means adapted to establish the desired seed population to be discharged from the seed planter during a predetermined travel thereof, second means adapted to establish the actual seed population discharged by the seed planter during the same travel thereof and means for comparing the desired and actual seed populations to establish any positive or negative imbalance therebetween.

2. The monitor of claim 1 wherein the first means comprises first sensor means associated with a seed plate of the planter, the second means comprises second sensor means associated with seed discharge means of the planter and wherein signal means are provided adapted to be activated when the desired and actual populations do not substantially correspond.

3. The monitor of claim 2 wherein the seed plate defines seed receiving zones in the form of pockets, apertures or the like and which is adapted to rotate to feed the seed to the discharge means; and wherein the first sensor means comprises first transducer means adapted to count the seed receiving zones during rotation of the seed plate.

4. The monitor of claim 3 wherein the first transducer means comprises a light responsive transducer such as a photo-transistor and a light source arranged such that the passing of a seed receiving zone will cause the light source to trigger the transducer.

5. The monitor according to claim 4 wherein the seed receiving zones are apertures and the light responsive transducer and light source are arranged on opposite sides of the seed plate so that the transducer will sense an aperture when such aperture is in register with the light source and transducer.

6. The monitor according to any one of claims 3 to 5 including a first counter which is adapted to receive a signal from the first transducer means whenever a seed receiving zone is detected.

7. The monitor according to claim 6 wherein the first transducer means is associated with a comparator and a variable resistor set at a 'predetermined threshold resistance, which signals the first counter.

8. The monitor according to any one of claims 2 to 7 wherein the second sensor comprises second transducer means which is adapted to be actuated by the passage of substantially each seed which passes through the discharge means.

9. The monitor according to claim 8 wherein the second transducer means comprises a light dependent resistor, a photo transistor, capacitor sensor, trigger or the like.

10. The monitor according to claim 8 or 9 including a second counter which is adapted to receive a signal from the second sensor whenever the passage of a seed through the discharge means is detected.

11. The monitor according to claim 6 and 10 wherein signals to the first counter and the second counter are passed to these via logic circuit gates.

1 2. The monitor according to any one of claims 2 to 11 wherein the signal means comprises and audio and/or visual alarm.

13. The monitor according to claim 12 wherein the signal means comprises a piezo buzzer.

14. The monitor according to any one of claim 2 to 13 adapted to discriminate between a positive and a negative imbalance between the desired seed population and the actual seed population by means of comparator circuitry.

1 5. The monitor according to claim 14 wherein the signal means is adapted to emit discriminative signals in accordance with a positive or negative imbalance between the desired seed population and the actual seed population.

1 6. A monitor substantially as herein described with reference to the accompanying drawings.

17. A seed planter including a monitor substantially as claimed in any one of claims 1 to 16.

1 8. A seed planter substantially as herein described.

1 9. A method of monitoring the functioning of a seed planter comprising the steps of establishing the desired seed population to be discharged from the seed planter during a predetermined travel thereof, establishing the actual seed population discharged by a seed planter during the same travel and, comparing the two seed populations to establish any positive or negative imbalance therebetween.

20. A method according to claim 19 wherein the monitoring for imbalance is effected repeatedly and consecutively during travel of the seed planter.

21. A method according to claim 19 or 20 wherein the seed planter includes a seed plate having seed receiving zones in the form of pockets, apertures or the like and which is adapted to rotate to feed seed to dicharge means, the desired seed population being established by counting the seed receiving zones on the seed plate during rotation thereof.

22. A method according to any one of claims 19 to 21 wherein the seed planter includes discharge means through which seeds discharged by the seed planter pass to the ground, the actual seed population being established by counting the number of seeds passing through the discharge means

23. A method of monitoring the functioning of a seed planter substantially as herein described with reference to the acccompanying drawings.