I am making a balloon cut off mechanism using Arduino. The Arduino uses GPS data to find the height of the balloon. So when a certain height is reached it has to allow current to pass through a nichrome wire to burn the nylon rope.
How do I use Arduino to act as a switch? That is, when a condition is reached, Arduino has to allow current to pass through. Can it be done using Arduino?
Is there a digital switch I can buy and control via Arduino? My search gave me suggestions to use a Triac. Is there a easier way?
Not really a SO question... but I've used this TIP-120 circuit in many projects with success. It's tolerant of abuse (handles high current, etc) and easy to put together with parts from Radio Shack costing a few dollars. (for your usage, the diode is not required).
Turning it on is as simple as digitalWrite(pinNum, HIGH);
Personally, I would use a mechanical solution as a release mechanism rather than trusting the vagaries of heating at high altitude and the higher power reqs.
Related
I'm trying to find a fitting module/component for a project, but have a hard time finding the right thing.
I need a PWM module/component that can provide a PWM signal and can be controlled via Arduino, preferably TX/RX.
I've used this one previously, and it works great, but it is bulky due to the screen and buttons which I don't really need.
It would be perfect to find the same module but without the screen and buttons.
What it needs to do:
Duty cycle 0-100%
Frequency 1-10 kHz
5 V preferably
Communication via tx/rx or other Arduino compatible protocol
1-2 channels
As small as possible
I've seen some Adafruit modules, but they have at least 16 channels which is not necessary. Would also work, but if I can find an even smaller alternative that would be great.
Any suggestions?
(And no, the Arduino's PWM signals do not work in my case.)
The standard Arduino analogWrite() can't do what you want without trickery, but most Arduino hardware can, so there's no real need for a separate PWM IC or module; you just need to code the Arduino's MCU's timer peripheral to do what you want.
You can do that "by hand", but I would try first to see if an alternative library like TimerOne can get you the PWM you specify. For SAMD21-based Arduinos there is this library (that I wrote), among others.
If you insist on having a separate module for your PWM, just google around (modules exist, but recommendations are not done here), or simply use a second Arduino of your choice as a dedicated PWM generator.
I'm working with the efm32gg380f1024 on a project.
I currently use the BURTC timer (ULFRC clock) as tick source and I would like to use the normal RTC timer(LFRC clock) as well.
Do they exclude each other or can I use both the same time?
I was wondering if someone has already experience with the GG-series of silicon labs and give me some hints?
also what I'm wondering, I do have both LFXO and HFXO on my board currently not used. when I initialize the external clock setup, can I disable the interal rcos since they are not used (??) and just need energy.
the target is battery powered and each uWs counts..
thanks
You have a couple of questions here.
Yes you can use the LETIMER (which is what I think you mean when you say LERTC) peripheral independently of the RTC. They are separate peripherals, but note that the LETIMER is clocked from the same clock as the RTC.
As for using the external crystal oscillators, you need only enable the clocking sources that you actually use. However, clocking sources and entry/exit of the various low power energy modes interact. It can be rather tricky and complex. I suggest you use emlib to control these peripherals and in particular to enter and exit lower power energy modes.
If power consumption is important to you, note that high frequency clocking of the processor core consumes lots of power. Of course this must be traded off with how long you remain awake before going back to a lower power mode and with any real time requirements you might have for processing. Pushing off work to peripherals and using DMA to perform data movement is generally a win. Expect to do a good bit of tuning and you will need ways to accurately measure the power consumption. Using internal RC oscillators for clocking may be sufficient and a lower power approach. The low frequency external crystals tend to be 32 KHz clock crystals and don't consume that much power. They are a good alternative to the internal RC oscillators if you need better frequency stability.
In my project i'll use modbus protocol for serial communication. There are more than 320 slaves which seperated equally in 2 groups(see image). Every 16 slaves are powered from the same supply and isolated from others galvanically(Master'll be isolated from all the slaves).
My first question is if there is a problem in this design?
Secondly I want to synchronise all the slaves via 10ms period pulses that are derived from master microcontroller. How can i achieve a robust synchronisation(what type of bus, single or differential signal, where to isolate)?
Here is an alternative one:
see picture
Many things can go wrong here. For starters, it will take a looooooong time for you to poll each and every one of your slaves. And your isolators will easily introduce delays beyond 2us to your sync signal.
Can you briefly tell us what are you trying to do specifically, eg. synchronized motion control? There are other alternatives used in industrial solutions.
Most of the synchronized motion control used in industrial systems are used to replace mechanical cams and eccentric gears, and thus usually called "electronic camming" in this field. Here's a list of techniques I had come across in my last job
A PLC which outputs multiple pulse trains, each commands an individual servo/stepper motor driver. The PLC will have to store all the motion profiles and do all the interpolations, so relatively simple drives can be used. But each actuator will need it's own pulse train lines, and there's just too much in your system.
Motor drives stores motion profile & does interpolation, and the motion is advanced/reversed by an external pulse train. This is a technique used in Delta Automation ASDA and Schneider Electric Lexium 23 model industrial servo drives. The motion profiles are either burnt into the drive's EEPROM beforehand, or written in through MODBUS. This is very close to what you are trying to do, but the difference here is the external sync pulse train is on a separate wire.
Real Time Ethernet. The target positions are periodically written to each drives at a specific interval. This can be done very rapidly at 100Mbps. As for the latency that occurs when writing to different drives, there is a built in mechanism that measures the latency of each drives, and this is then compensated accordingly later. Cool eh? The one that I had saw, but never really used is EtherCAT by Beckhoff.
I worked mostly with method 2 in the past, and from those experience you needs might not need to be so stringent. Here are my recommendations.
It will be perfectly fine if your sync signal is delayed a little if your mechanism has no risk of collision if the timing is off by a little. But lost pulses cannot be tolerated as one of the actuators will be out of phase. Don't scrimp on your sync & communication cable quality, shielded twisted pair if possble, and connect them properly.
If the communication line is not too long, isolators are not needed. I had worked with lines up to 8 meters without the need for isolators or repeaters. Instead I am more worried about the number of spur (branch) connection on your RS485 bus. If possible, connect everything to your 2 main buses directly.
If this is a production system, there might be a problem. When the system is running in sync motion mode, there is no way to monitor the actuators as the communication lines are now occupied. This will not be acceptable on a real world application, but if this is just a proof of concept design, go for it.
I am trying for some time to make my own rfid reader following the ideas on the DIY FSK RFID Reader. My primary problem now is that i do not have a specific rfid tag to test the reader so i decided to make my own using also an arduino uno. The only information on the internet which i found is at FSK MODULATED SIGNAL.
I really need to know how to write the code to transmit the id from the tag to the reader. I mention again that the tag needs to work at a 125 kHz frequency and needs to use FSK modulation.
You won't be able to send data to the Reader without special hardware, just adding a wave on some antenna doesnt work for RFID systems with passive tags.
Reason is, RFID-Tags do not actively 'send' waves to the reader, instead they 'modify' (modulate) the reader's field by producing load on the antenna.
Imagine when the tag had an LED switching on and off while receives energy from the reader's RF field by inductive coupling. The reader will notice a change in it's own field when the LED on the TAG turns on/off as the more/less power is drained from the RF field.
This method is used for the TAG -> Reader communication, which is nice for several reasons:
TAG gets power from inductive coupling anyways, modulating the signal through load is alot more power efficient than using power for actively sending.
Smaller/Easier/Cheaper, needs less hardware on the TAG, might even need a separate antenna for sending
Harder to snoop communication as the modulation is harder to detect from distance
tl;dr
A bare ardouino doesn't have the required hardware onboard to modulate the reader's RF field.
Sidenote: transponders are not expensive, you get them for a few bucks. The LF transponders based on T55x7 are really nice for playing around as the can be configured for various modulations (PSK/FSK/etc in different modes), bitrates and more, however the usually come with Manchester modulation enabled by default.
I have some old relays that controlls an hydraulic motor.
I want to control it with my Arduino. Is this possible?
The relays used are:
DIL 00 52 from klockner moeller.
this is the situation:
I have experience with the arduino but not that much about electrical schemas?
Is there someone that can help me?
Is this equipment functional now?
The part you have pictured looks like it is for an engine lathe, not a pump.
The amount of rust in the box and corrosion on the overloads and relay would make me think that it has run either outdoors, or in a corrosive environment for quite a while with the door open. Why would you run it with the door open?
Because you have to continually reset the overload and or adjust the timer, or tap on the contacts to get them to engage. Either way, this thing is a mess.
The relays you have shown will interface easily with your arduino, but I WOULD NOT replace what's in the cabinet with these.
The set up in this cabinet is for three phase power. The one on top is the main contactor, and the two side by side units are for reversing the motor. Something you don't want to do with a pump.
My advice to you is to find an electrician before going any further with the power end of this project.
it is possible but probably that relay won't fit the load.
You have to be sure to use relay that can sustain at least the same load and spike current (and voltage), or you many bad thing may happen, like melting togheder the relay contact or burn your house down.
i can't see the code on the relay in the second picture, neiter you had given the load information, so i can't help you more.