Hi.
Thank you for this brilliant piece of art !
I have implemented the kit in my arduino robot lawnmower. It works beautifully. My perimeter wire is appx. 430 feet 2,5mm2 multistrand UL copper wire.
Though I do wish that the pickup distance could be a bit longer. I have 1-2 inches on inductor 1 before there is a tiny detection. Inductor 2 works up to 5-6 inches away.
Why could this difference be ?
Several previous posts a stronger signal or longer pickup distance are mentioned.
Do you have a suggestion on how this could be done by external amplifier. Maybe an example or a sketch ?
Would more âgruntâ on the wire give a stronger signal that could be picked up from a longer distance than 2-3 inches?
Anything would be appreciated. Thank you in advance !
Thank you for your feedback. Happy to hear that you like the kit.
In theory, both inductors should have the same detection distance since the 2x inductors included in the kit are the same component (from the same manufacturer) and the signal detected on each channel is amplified the same way (also same gain).
Could you verify that the components are soldered in the correct places on the sensor board (the 1M and 10K resistors specifically) ?
Also, what power supply are you using on the generator board ? We suggest to increase the voltage (to a maximum of 15V) and the current to 3A.
To improve the performance of the kit, you can also rotate the potentiometer on the generator board such as you have the longest distance between the inductor and the perimeter wire. This potentiometer varies the square wave frequency of the generator board from 32 698Hz to 43 956Hz as the resonance frequency of the tank circuit on the sensor board can vary due to the manufacturing tolerances of the components in use.
I have been having issues with my landroid doing circles intermittently. I brought up the troubleshooting guide and it recommended replacing the perimeter wire. So Iâve completed that. It still does circles intermittently. So here I am. Next step is to order this kit and replace the components. Has anyone had success with this kit on a landroid? Thanks.
It would be better to look for a replacement that is made specifically for the Landroid. As the two systems are most probably different and wonât be compatible to work together.
Hello, I have built the same signal generator but I have an issue. When I check the frequency of the output after setting around 34k, I see that it swings between 33.9k and 34.1k. Is it about the quality of 1uF (C5)?
The frequency of the generatorâs output wave can be calculated with this formula :
f = 1.44 / (( R1 + 2 * (R2 + Rpotentiometer)) * C3 )
Therefore, the accuracy of the generatorâs output wave frequency will be dependant of the accuracy of the parts above (R1, R2, Potentiometer and C3)
Hi bdaouas,
Thank you for posting this. From your knowledge, if there are (2) different am perimeter wires (a robotic mower and an underground pet fence), is there a way to try to reduce interference if I need to run one across the other at 90 degrees in (2) different places?
I donât know the frequencies that either of them use and donât think either allow changes.
If by interference, you mean crosstalk, you shouldnât have electromagnetic interference issues since your two perimeter wires run one across the other perpendicularly. Crosstalk usually happens when wires are run one next to the other in parallel.
Hi,
I have an issue with this module. I think that @jcf was right. I explain my problem:
On the first module I bought, I had one sensor with good behavior. The second one saturates at maximum value, even when the sensor is far from the perimeter cable.
I have analysed the situation on most of the pins to verify what was happening. I saw that after first stage of amplification, an offset exists and this offset is amplified by second stage up to saturation.
I have bought two new kit. For first kit, the second sensor was working properly, but the first one was saturating.
on the last kit, both sensor are saturating.
I verified all continuity, everything seems to be clear.
The comment of @jcf points a lack of high pass filter between both amplification stage. Unfortunetly it seems to be difficult to adapt the board for that. I intend to test it on a new kit.
I am a bit surprised being the first to have this problem. Could something else explain my problem?
I purchased and assembled an arduino, a motor shield, the signal generator and sensor kit, and a robot chassis with motors and wheels, and I am now developing the sketch and testing the circuitsâŠand Iâm new at this. Rather than a perimeter wire, I plan to make this into an inductive guidance/wire following robot. Using the analogread function, Iâm getting a scrolling readout same as listed above (400-780), but this raises 2 questions:
Why do the readings only fluctuate when the sensor is practically touching the signal wire? I thought this would start fluctuating within 15 cm of the wire.
I thought the raw values were to vary from 0 to 1024, according to the guide, but the scrolling example above and my own date show 400-780. What am I doing wrong?
I have not adjusted the potentiometer on the generator since I donât know what Iâm looking at.
I answer to myself:
I bought some other quad-op amplifier with the same pinout. I have built one of the module with a support so that i can exchange the amplifier easier.
I have tested .
one other LM324N works very well.
Other amplifier have similar problems. So I realy think that @jfc is totaly right. First stage creats an offset wich is amplified by second stage.
It could be a nice idea to propose an update adding a filter between the two amplification stage.
I am not very experienced in that, but I would say that a high pass filter with a limit at 100hz could solve this issue. This is far enough from the module frequency (>30kHz) and high enough to be sure that any constant value will be canceled.
