So I have been using the DFRobot Weighing Module (Gravity: Arduino Digital Weight Sensor - DFRobot) with my 50 kg load cell (http://www.aliexpress.com/item/Parallel-Beam-Load-Cell-Sensor-50kg-110LB-Aluminum-Alloy-Material-Shielding-Cable/1082699513.html). Everything worked fine the first few times I used it but now when I hook it up it gives me a great shock! Even after I take out the battery it can still shock me for minutes afterwards. It has been doing this a few times and as a result 2 of my weighing modules, an LCD screen and an arduino are not functioning. Is this because of the load cell malfunctioning? or not being compatible with the arduino or weighing module? The load cell does have 5 wires instead of the usual 4 so the extra one does not get screwed into the weighing module but gets put to ground.
If you need to see my wiring I can provide a picture, I also have a multimeter at my disposal.
It sounds to be most likely like a problem with static charge to me. Try grounding yourself to something earthed like a radiator before touching any part of the circuit or use a conductive wrist strap.
When you say that you have connected the spare wire to ground what exactly do you mean. Ground on the Arduino, ground wire from your power distribution, something else?
It could be static charge, or more worryingly a problem with a defective mains power
supply. The latter possibility is potentially a serious risk to life and limb and needs checking
out. It could simply be a case of needing to earth your Arduino ground though.
I had my arduino shock me too. The USB connector metal case had 70V on it. Turns out it was a bad power supply unit. Switched to another one and it solved the problem. The USB outer case on the arduino has this peculiar wiring. However this saved my board from destruction i believe.
I used it but now when I hook it up it gives me a great shock!
If it's one quick "zap" when you first touch it and then it stops, that's a static discharge. And if that's the case, the static charge is on your body... You are shocking the Arduino, it's not shcking you! You can try different shoes, or try some anti-static spray on the carpet, or maybe try adding some humidity to the air.
If it's giving you continuous current until you let go, there is some high voltage leakage that shouldn't be there. Grounding the case to earth ground should git rid of it, but it' would be best to fix the root cause and ground it for safety.
Thank you for all of your responses! Attached is a picture of my circuit diagram, load cell, power source (9V battery), LCD screen with soldered header pins, weighing module and load cell hooked/unhooked up and a closeup view of the female ends of the wires that I am using.
As seen in the picture my load cell has 5 wires (E+, 2 E-, S+, S-) from it and the weighing module only has room for 4 so I put the other E- to a grounded wire on the arduino. This was working fine in the early stages and was performing as expected in ambient conditions with no vibrations or dust. When I put it in the conditions with vibrations and dust, the screen then flickers and the LCD screen shocks me when I would touch it. I would unplug the 9V power source and after minutes of sitting there the LCD would still give me a shock.
Could wires such as mine when disconnected cause this much of a shock? I could solder new wires on everything if that is the issue, they seem kind of wimpy and the connections could be made better. Or is the issue that the load cell is not compatible with the arduino/weighing module?
Is there a way to check if the load cell is the issue without risking my remaining equipment? I’ve already fried an arduino, 2 weighing modules and an LCD screen.
TomJohn:
This was working fine in the early stages and was performing as expected in ambient conditions with no vibrations or dust. When I put it in the conditions with vibrations and dust, the screen then flickers and the LCD screen shocks me when I would touch it. I would unplug the 9V power source and after minutes of sitting there the LCD would still give me a shock.
This is new information. It still sounds like static charge to me. Is there any way that the dust it is exposed to could be charged? Where does it come from?
It would be a good idea to connect the ground terminal of the Arduino to a real ground such as a the mains protective earth or a grounded water pipe. That should stop any charge building up on it.
sorry to say that no one photo offers and value. I can guarantee that a battery that is not connected has nothing to do with you getting shocked.
what is needed is a photo of the mess on the table. we all have a mess of wires so you should not be ashamed of a jumble.
we need to see the whole lot, all connected.
The photo you did not show was that of the load cell weigning the car batteries that have wires dangling and brushing the metal chairs while you are standing in salt water, next to the power plant.
Ok, hear you loud and clear. I will show some more pics of the actual set-up which is a jumble of wires. I have spent some time taping and soldering so it should help with seeing the connections.
(WiresToLCD): The red tape holds all of the voltages (soldered together), the black tape holds together the ground wires (soldered together) the yellow tape goes to A3 which is connected to SCK on the weighing module, the black tape at the bottom goes to A2 which is connected to DOUT on the weighing module.
(WiresToLoadCell): The black tape on the top is the incoming wires connected to DOUT on the module, the yellow at the bottom is the incoming wires attached to SCK on the weighing module. I soldered thicker wires onto the load cell to plug into the weighing module and I soldered the extra ground wire from the load cell into a wire in the yellow tape’s collection.
I couldn’t upload a video of the error that I am getting so I had to take several screenshots of it:
VideoScreenshot1) I plug the 9V battery into the arduino, the screen does not light up
VideoScreenshot2) I remove the voltage from the soldered header pin on the LCD, the screen lights up
VideoScreenshot3) The screen shows the proper text although it is not as bright as it should be. The voltage is still unplugged as seen.
VideoScreenshot4) When I plug the voltage back onto the header pin the screen powers off.
This is the same error that was happening before that leads to the shocking which has happened before, how can I avoid it?
TomJohn:
This is the same error that was happening before that leads to the shocking which has happened before, how can I avoid it?
As I have repeatedly said, it is damage due to static. How do you avoid it?:
Google "antistatic precautions" and learn a bit about the problems.
2 As I have said before, connect your Arduino ground to a real ground. If you don't want to do this directly you can do it via a high resistance, say 100 k. That will prevent charge building up on the circuit.
Don't use duct tape to hold it to a plastic container. When you pull it off the adhesive generates a static charge.
Make sure you don't get yourself charged up. Do you ever get a shock when touching a large metal object? If so that will kill the circuits.
OK, so it is not connected to the mains at all, either through a PC or anything else.
I suspect then you are in a very dry, perhaps cold environment. As Tom says, that plastic container could be the culprit for static electricity.
Love those garden gloves! Is that your static protection? That may be better or may be worse for production of static against the plastic container. Better move it elsewhere and stick to working on a (clean?) wooden bench. And keep your trousers away from it.
Now the discriminator between static and mains leakage, is that static goes "snap" when you touch it and is limited to that single impulse. Mains leakage "tickles" badly as long as you keep touching,
If there is any doubt, a multimeter on AC Volts range should be able to indicate troublesome mains voltage on anything compared to the copper water pipe. Of course, you do have a multimeter ...
You can try different shoes, or try some anti-static spray on the carpet, or maybe try adding some humidity to the air.
