DAQ - Arduino on Crack! - Page 1
Forum section: electronics / general

author: olsenn
author_rank: Frequent Contributor
timestamp: February 07, 2012, 12:05:04 am
content: Hi folks,I'm wondering if anyone here knows where I might find a cheap (less than $200) digital I/O DAQ with lots of input protection? Basically I'm looking for an Arduino that has a hard case and won't blow up if I manually force 60V into one of the pins (whether it's configured for input or output). It doesn't need to be any faster than the Arduino; in fact, even 1+ MHz will do fine. I want a device that won't blow up if I connect it across an inductive load without a flyback diode. Lastly, it doesn't need to source much power (10+ mA).It would be a big bonus if this device has support for LabView, but that's not a requirement.If only Fluke made microcontrollers!

author: amspire
author_rank: Super Contributor
timestamp: February 07, 2012, 12:58:01 am
content: You can use any DAC you like. It is just that after the DAC, you need an opamp buffer amplifier that has a series resistor between the opamp output and the board output terminal which is where the the feedback connection will also connect, and you have to add protection diodes or zeners to stop the opamp output or inverting input going outside the opamps supply rails. So it is a case of using any convenient labview friendly DAC, and adding a $2 protected buffer stage.It is hard to say anything more without more details like available supply voltages, DAC accuracy, DAC speed, DAC voltage range, is the DAC output bipolar (ie +/- output), the nature of the inductor spikes. Does the protection circuit still have to work when the buffer power supply is off? It is likely you will need more then a 5V supply to power the buffer opamp. A +/- 15V to the buffer circuit would be the easiest design.Richard

author: Jimmy
author_rank: Regular Contributor
timestamp: February 07, 2012, 01:03:09 am
content: this may helphttp://ruggedcircuits.com/html/products.html

author: olsenn
author_rank: Frequent Contributor
timestamp: February 07, 2012, 01:56:53 pm
content: That Ruggeduino looks pretty good for only $40. However, I am really looking for something a little more polished (must have a case for instance), professional and even more protected (optical isolation etc). That being said, I am also willing to pay for for it. I am not looking for a toy to add to any specific project right now, but rather I am looking for a tool that I can add to my bench and use whenever I need to stimulate a digital circuit or use to acquire data.Does anyone know how the myDAQ holds up to stress? The National Instruments USB-6525 in particular looks to be a pretty good contender, but a tad more expensive than I'd like

author: Genesisfactor
author_rank: Newbie
timestamp: March 02, 2012, 07:22:35 pm
content: There was an interesting site about using the arduino as a daqhttps://sites.google.com/site/measuringstuff/the-arduino#TOC-Yeah-Well-One-Hundred-Samples-SeemsHowever, you are correct that this is just not versatile to be used as a general purpose DAQ for NI (talking about input voltage, currents, and other things).Problem with the NI is that i experienced a complete loss of stability in the output signal when i started to record a previously working PID circuit in a lab with one of their $500 USB ones. Wasn't too thrilled with that--even though the software was acting like an o-scope, took in and replicated a 1V 1Hz square wave, and was recording-- because it was on an Intel i7 processor machine! I am not sure what could have been to run it on better to keep the stability. I wasn't alone in my finding of a class of 80.If DAQ is what you need, i'd say grab a decent one, and if you are a student, try to get the student discount!My two to choose from are the "MyDAQ",as deal with micrcontrollers had has a 200kSa/s, and available to students only, and you can get a host of software with it for $200, and the USB-6009, as it has 8 Analog in and 2 out, but runs at 48kSa/s and costs $279. There is a student's only version for the same price that comes "bundled" with LabView.