![]() ![]() If you can source one with a suitable slot spacing, narrow beam, a recessed detector (if available) and then mount it on a rigid, finely height adjustable mount, you might just be able to tweak it to break the beam with the slightly longer screw. If you haven't already considered it so far, another cheap sensor option could be a photo-interrupter. Likewise, the screw clamp needs to reliably hold the screws in an identically positioned grip for each screw. I imagine your conveyor will need to be extremely stable with little to no vibration. Wow: detecting just 0.5mm difference in length. Open to other suggestions for sensors but I just have some piezo and op amps available. I have a belt conveyor that holds the screws by the head, leaving them hanging down, making the thread tips there to be checked. ![]() The only difference between them is one is 3.5mm thread length, the other is 4. They're very small, 3mm head diameter, 1.5mm major diameter. If ((redSensorReading > 0) & (redSensorReading < thresholdMax))įor reference I'm trying to sort two screws that are nearly identical. redSensorReading = redSensorReading /100 RedSensorReading = analogRead(redKnockSensor) I had also thought of a load cell that could measure grains, as these are very light parts, but looking into a couple videos on how to make one like some of the YouTube "weigh an eyelash" ones it seems pretty tough for me to do with such limited electronic experience and I would have to redesign the mechanics of the setup and the scales seems pretty finicky too.Īs you can see I am open to any practical solution haha.Ĭonst int ledRedPin = 13 // longParts red LED signalĬonst float redKnockSensor = A0 // input for long parts piezoĬonst int thresholdMin = 2.0 // min piezo voltageĬonst int thresholdMax = 25.00 // max piezo voltageįloat longParts = 0 // Counter reset for long parts. I had tried the KY-036 touch sensor externally from the setup and thought it was good to go, holding the screws by the head with needle nose pliers making sure to only touch the rubber grips but I guess my hand was still conducting enough through to trigger the sensor? When I put the touch sensor in the setup and the belt was driving the sensor wouldn't read. I thought about something like the Pixy cam through a magnifying glass or something, but that's really best for identifying color differences it seems, where as these two screws are both silver (titanium) so that seems out. I know there are vision systems that can distinguish this kind of difference but I was trying to build something for a couple hundred bucks tops, not spend $2000+. On a side bar, I'm not set on the piezo, its just like I said some stuff I had on hand. The dragging of these screws against the ceramic is very light obviously. I tried adding more resistors to see if it would boost the voltage more but no luck, hence why I started thinking about the amplifier. 10 etc but it was overall still inconsistent, still reading 0 about 1/2 the time. I then tried dividing the signal by 100 and was getting a much more consistent reading, things like. I was using a threshold also because I thought I would have a range and had heard the piezo could pick up other vibrations so I wanted to limit the signal. With just the straight reading I was getting 1.0, sometimes 2.0 but it was very inconsistent. I was using a 1M resistor before the piezo's ground and signal wire and using an analogue input for the reading. Hey DVDdoug, well I guess I'm glad I started in the right spot. Are you using an analog input? Run the Analog Read Serial to see what kind of readings you're getting.Īnd, I assume you're using a pull-down resistor? A higher value resistor (maybe 1M) will allow a bigger signal from the piezo. ![]()
0 Comments
Leave a Reply. |