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| amabelgokey:
I think it's OK only if you don't do it as an open advertisement. |
| SomeGuy:
--- Quote from: tautech on March 06, 2022, 08:16:30 am --- --- Quote from: SomeGuy on January 22, 2022, 01:51:37 am ---Hey everyone, new here but have been reading for a little while. I've started working on an RC project (building a wheeled RC tank from scratch) and was researching some electronics equipment and came across this place, impressed with just how much information there is here. Helped me decide on getting a Siglent SPD3303X-E bench power supply and Siglent SDS1104X-E scope. The bench supply was pretty much a no brainer that I needed one, lots of low voltage DC equipment to power up and test and a lot easier/less risky than plugging in big battery packs. The scope I ended up getting because I ran into some issues with the RC receiver and motor drivers not talking nice to each other. Helped me understand what was going on with them. Anyway, I hope this isn't against the rules, but I am documenting the build on YouTube if you want to check it out: https://www.youtube.com/channel/UCBwA36YGRBRyjJd-ZZM7qLw I have part 1 up now, and explains that RC/driver problem I ran into. I'll probably get part 2 up this weekend as my new motor drivers arrived today. Also a couple "shorts" (less than 1 minute videos) of unboxing of both pieces of Siglent gear I just got, nowhere near as good as some of the deep dive videos the guys here have done, but I'm also new to this YouTube thing...I'm actually learning electronics, YouTube, and machining (recently got a metal lathe) all at once for this project :) Anyway, nice to be here and I'm sure I'll be using this place for more research as I work through this project. Cheers! :-+ --- End quote --- FYI SPD3303X-E have a susceptibility when powering motors that provide regenerative braking that might exceed their reverse voltage protection so best advice is to install a beefy series diode to protect the PSU. It's not a common problem and only one unit I'm aware of has suffered in this way but this is something the novice can easily overlook. ;) --- End quote --- I haven't used the PSU to power the actual motors for this project and definitely won't. The motor drivers I'm using specifically say to use a battery as well. |
| RJSV:
Hello someguy: Hope folks here are helping! One good rule, (IMO), for criticism, is that NOW, one is obligated to see that person benefit. So, took a second, before I start my own day, to illustrate the response (from Kleinstein). Please see diagram, of basic low resistance in the supply line. SHUNTS, I think of more like less than one tenth (ohm)...but that's just me. How about, we look at just TWO cases, as you've outlined. Suppose the uP sleep mode is at 200 uAmps, and suppose running at ave. 85 mA... That's, maybe your best quick guess, before starting anything. Grab your 0.58 ohm and do first glance, at the PC Board waveform, maybe some noise on that but the PC circuit generally has cap. and then regulator, so that input point shouldn't be wildly noisey (?) So, a half-ohm, try expecting a drop of: At 85 mA, that's an easy 85/2 = about 43 mV Notice that has fairly good resolution...(Don't get all hung up on wanting an A to D converter show 'full scale' for best accuracy. I believe it's easy to get into false 'overconfidence', that lots of digits equates to 'lots of accuracy... On the low end, that nominal 200 uAmps load current brings a (less accurate) voltage reading, of 100 uV. My (Velleman) DMM appears to only show the first digit, on the '100 mV' scale. (The low 00.1 mA is what you see on meter display.) But you can see, the point Kleinstein had, about not putting in too much supply drop, or the usual regulator does not get sufficient input voltage. Here, you get something like a tenth volt drop...less than what normal battery use involves. (More response later) |
| SomeGuy:
--- Quote from: RJHayward on March 06, 2022, 08:16:02 pm ---Hello someguy: Hope folks here are helping! One good rule, (IMO), for criticism, is that NOW, one is obligated to see that person benefit. So, took a second, before I start my own day, to illustrate the response (from Kleinstein). Please see diagram, of basic low resistance in the supply line. SHUNTS, I think of more like less than one tenth (ohm)...but that's just me. How about, we look at just TWO cases, as you've outlined. Suppose the uP sleep mode is at 200 uAmps, and suppose running at ave. 85 mA... That's, maybe your best quick guess, before starting anything. Grab your 0.58 ohm and do first glance, at the PC Board waveform, maybe some noise on that but the PC circuit generally has cap. and then regulator, so that input point shouldn't be wildly noisey (?) So, a half-ohm, try expecting a drop of: At 85 mA, that's an easy 85/2 = about 43 mV Notice that has fairly good resolution...(Don't get all hung up on wanting an A to D converter show 'full scale' for best accuracy. I believe it's easy to get into false 'overconfidence', that lots of digits equates to 'lots of accuracy... On the low end, that nominal 200 uAmps load current brings a (less accurate) voltage reading, of 100 uV. My (Velleman) DMM appears to only show the first digit, on the '100 mV' scale. (The low 00.1 mA is what you see on meter display.) But you can see, the point Kleinstein had, about not putting in too much supply drop, or the usual regulator does not get sufficient input voltage. Here, you get something like a tenth volt drop...less than what normal battery use involves. (More response later) --- End quote --- I have literally no idea what you just said :( |
| RJSV:
MY BAD, sorry. That was a misfired post, was supposed to send to the fellow doing processor current sensing... sorrysorry |
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