hybridfree/eevblog-posts huggingface dataset:
Rising and falling edge clocked data transfer - Page 1
Forum section: electronics / beginners

author: mriPaul
author_rank: Contributor
timestamp: September 09, 2019, 01:33:49 am
content: I was looking at some internal data transfer today on some equipment that is loading a register(s) and I see what looks like both rising edge keying and falling edge keying. For example, on one line, there is a clean clock running at about 4MHz. On other lines, there is data. At some times, the data is at the rising clock edge. (meaning all of the data values at the clock falling edges are zero. The data pin transitions between each clock cycle) At other times, the data is on a falling clock edge. Sometimes, the data appears mixed on the same line. (A packet of rising and a packet of falling on the same line.) Is this a standard protocol and if so, what is it called?

author: MosherIV
author_rank: Super Contributor
timestamp: September 09, 2019, 06:57:18 am
content: Hi. There is a standard serial bus called SPI.It does allow for data to be on rising edge or falling edge.

author: mriPaul
author_rank: Contributor
timestamp: September 09, 2019, 08:39:41 pm
content: I think the answer is as close as my RAM. It looks like a process called Double Data Rate (DDR).

author: helius
author_rank: Super Contributor
timestamp: September 09, 2019, 08:58:45 pm
content: Without knowing the setup and hold specifications for the dataand controllines you are shooting in the dark.Some lines may be sampled at the rising clock edge, which requires them to be driven at the falling edge. Others may have different timing requirements depending on other context, for example, writes are different from reads. This is all a far cry from double data rate.

author: ejeffrey
author_rank: Super Contributor
timestamp: September 09, 2019, 10:16:33 pm
content: Some scope captures would be helpful to illustrate what you are talking about.Generally DDR transfers data on both rising and falling edges to double the data rate for the same clock. It sounds like in your case each transaction is either on the rising or falling edge not both, which is not what you expect from DDR. It would also be a bit unusual to have a DDR interface at 4 MHz, although that can happen if you have an interface designed for much higher speed but run slower in this instance.SPI can operate on either edge but only uses one at a time. It is theoretically possible to have a bus with multiple slaves using different clock phases, and have the master switch for each transfer but I have to say that would be extremely unusual.
RJ45 LEDs - Page 1
Forum section: electronics / beginners

author: bhj99
author_rank: Contributor
timestamp: May 28, 2023, 02:03:07 pm
content: Hi all,I am seeking some advice on how to make use of the activity and speed LEDs that are integrated within an RJ45 connector on a PCB design I'm working on when I do not have access to the Ethernet PHY GPIO that would normally control these LEDs. I'm basically breaking out a 1000BASE-T interface from an single board computer (SBC) that has a PCIe-to GbE MAC/PHY that connects to the processor chip. All that is available from the SBC are GPIO from the processor itself and I have a local GPIO expander device used for status and control on my end. From my understanding, the LEDs should be controlled by the Ethernet PHY chip which communicates on the link. Should I simply no connect the LEDs, or can I purpose these in some useful manner? Any feedback is appreciated!

author: Whales
author_rank: Super Contributor
timestamp: May 28, 2023, 04:28:25 pm
content: If you're running Linux then yes it can flash LEDs on GPIO pins when network activity occurs.https://www.kernel.org/doc/html/latest/leds/leds-class.htmlhttps://openwrt.org/docs/guide-user/base-system/led_configuration<-- how I've interacted with this in the past, but you're probably not using OpenWRTAlso checkout /sys/class/leds/ on a computer running LinuxSidenote: every PHY chip I've seen uses these LEDs differently. There is no standard, other than at least one LED (typically but not always green) somehow flashing when data is sent and received.
RJ45 Modbus cable to D9 connector - Page 1
Forum section: electronics / beginners

author: Boardwalk
author_rank: Newbie
timestamp: June 06, 2016, 01:23:21 am
content: Hi people,I have a stripped RJ45 cable to whom i need know how to make the wire connection in a D9 connector, in order to match the pinout of a MPI-Bus adapter.How should i connect the wires from the RJ45 cable to the D9 connector?Thank you in advance,Boardwalk
RMS-DC converter LT1968 doesn't work properly - Page 1
Forum section: electronics / beginners

author: georgfour
author_rank: Newbie
timestamp: May 07, 2016, 05:49:37 pm
content: Hello!I faced with problem - RMS-DC converter LT1968 doesn't work properly as it should.I have scheme that is attached below.I connect input of J3 to 1kHz meandr with peak-to-peak 2.72V and switch on first voltage divider with SW1 and see weak 75mv at the output of LT1968At IN1 input i have properly 1.32V peak-to-peak signal that is raised at 2.5 voltage with help of divider at IN2 input.If I switch on SW2 (and switch off another two) I get 51mv.If I switch on SW3 (and switch off another two) I get 37mv.If I switch off all switches I get 30mv (what???).I simulated this scheme and it works great (screenshot below).All contact is fine and power too.Also attach photo of pcb.Thank you very much for help and sorry for my language.
RMS Ripple Current Rating (RRCR) Output Cap - Page 1
Forum section: electronics / beginners

author: chimera_786
author_rank: Regular Contributor
timestamp: April 04, 2012, 08:30:34 am
content: Well I am been designing a product at work and we've decieded to use an LM2576 ADJ. Everything is fine. However, I am not satisfied when it comes of to the RMS Current rating of the output/input caps. According to the data sheet of LM2576:1- Input Cap should have a RMS ripple current rating of 2.14 A (RMS) and 1000uF rating (overkill)2- Output cap should have a RMS ripple current rating of 1.65 A (RMS) and 1000uF rating (overkill)I figured I can use same rating for both the output cap and input cap (2.14 A-rms being the case).However, my question is:IF I parallel say, two 680uF (two on the input and two on the output), would they share the RMS ripple current requirement? As in, would the RMS requirement be split into two becaz now I have two "banks" for the circuits current requirement.OR should I just use 1000uF @ the required RMS current rating? (kind of an expensive option though)Price vs Reliability .. the age old dilemmaAll insight is appreciated!!

author: amyk
author_rank: Super Contributor
timestamp: April 04, 2012, 08:57:43 am
content: Yes, the ripple current will be divided between the two caps.The ESR will also be halved.

author: chimera_786
author_rank: Regular Contributor
timestamp: April 04, 2012, 10:15:31 am
content: Quote from: amyk on April 04, 2012, 08:57:43 amThanks and I also confirmed that with the following info. Even though I am using the LM2576, the same principle applies based on another family member of theSimple Switcherfamily of National Semi (now owned by TI).Excerpt from LM2676 data sheet:The RMS current flowing through the input capacitor is equal to one-half of the maximum dc load current so the capacitor should be rated to handle this.Paralleling multiple capacitors proportionally increases the current rating of the total capacitance. The voltage rating should also be selected to be 1.3 times the maximum input voltage. Depending on the unregulated input power source, under light load conditions the maximum input voltage could be significantly higher than normal operation and should be considered when selecting an input capacitor.The input capacitor should be placed very close to the input pin of the LM2676. Due to relative high current operation with fast transient changes, the series inductance of input connecting wires or PCB traces can create ringing signals at the input terminal which could possibly propagate to the output or other parts of the circuitry.
rms  week  owon - Page 1
Forum section: electronics / beginners

author: J4e8a16n
author_rank: Regular Contributor
timestamp: July 20, 2015, 02:54:23 pm
content: Hi I am trying to understand week rms from my oscilloscope.Cyrms is for the first cycle of the wave.And mean rms?What is week?Thanks for your attentionJPD
robomow lawnmower software robotools someone? - Page 1
Forum section: electronics / beginners

author: tjabas
author_rank: Newbie
timestamp: May 12, 2023, 07:37:51 pm
content: Hi!im looking for the robomow software called robotool, its a windows based software used for updating and programming the robomow lawnmowers.i cant seem to find it anywhere, but maybee someone here as a copy?

author: barshatriplee
author_rank: Regular Contributor
timestamp: May 13, 2023, 07:48:57 am
content: I only could find this app link.https://robomow-app.soft112.com/

author: agehall
author_rank: Frequent Contributor
timestamp: May 13, 2023, 09:14:03 am
content: Guess your google karma is pretty bad - third link took me to the ByggaHus forums that then linked me back to this thread here:https://www.eevblog.com/forum/projects/looking-for-robomow-rm-toolkit/
Robot encoder signals - Page 1
Forum section: electronics / beginners

author: jdolecki
author_rank: Contributor
timestamp: November 24, 2023, 05:07:30 pm
content: My Scorbot robot arm has encoders on each axis.The documation say it uses a phototransistor.The encoder is connected to 5v dc with a 39 ohm resistor to limit current.I have the a/b outputs connected to my scope.The robot manual says “ a clean square wave”So I’m not understanding why my signal looks the way it does and how to fix it.

author: rstofer
author_rank: Super Contributor
timestamp: November 24, 2023, 05:13:06 pm
content: Is your scope set for DC Coupling?

author: BeBuLamar
author_rank: Super Contributor
timestamp: November 24, 2023, 05:15:46 pm
content: Do you have the brand and model number of the encoder. It should be a quadrature encoder with A, B pulses plus the Z pulse.

author: jdolecki
author_rank: Contributor
timestamp: November 24, 2023, 05:27:16 pm
content: Yes sir

author: jdolecki
author_rank: Contributor
timestamp: November 24, 2023, 05:27:53 pm
content: Added data sheet

author: jdolecki
author_rank: Contributor
timestamp: November 24, 2023, 05:29:27 pm
content: Data sheet

author: jdolecki
author_rank: Contributor
timestamp: November 24, 2023, 05:32:13 pm
content: Pic of unit

author: MarkT
author_rank: Frequent Contributor
timestamp: November 24, 2023, 09:40:34 pm
content: That variant is open-collector NPN output so the outputs must have pull-up resistors for it to work at all.How have you wired it exactly?
Robotics  - Page 1
Forum section: electronics / beginners

author: electrolux
author_rank: Regular Contributor
timestamp: February 04, 2014, 11:15:11 am
content: Can anyone supply me with circuit diagram and code for a Arduino line following robot?

author: Rerouter
author_rank: Super Contributor
timestamp: February 04, 2014, 11:29:00 am
content: There should be plenty of examples online if you go searching, other than that it is as simple as a staggered if statement, you have 2 spaced sensors and your on a line with only 1 sensor getting a reading, if the second sensor sees the line it is curving one way, if the first sensor looses it without the second picking anything its either end of line or curving the other direction(a basic test like this is why so many spin in one direction when they loose the line)

author: Kohanbash
author_rank: Regular Contributor
timestamp: February 04, 2014, 03:03:41 pm
content: HiHere is a line following robot and its code from the Society of Robots using an Atmega.http://www.societyofrobots.com/robot_mobot_2007.shtmlhttp://www.societyofrobots.com/downloads/Mobot_2007_v1.zip

author: electrolux
author_rank: Regular Contributor
timestamp: February 11, 2014, 10:23:11 am
content: Quote from: sdk32285 on February 04, 2014, 03:03:41 pmThanks it's brilliant the robot even looks good. I don't really mind it being Atmega.
Robust Serial Communication - Page 1
Forum section: electronics / beginners

author: Md_Aslam
author_rank: Contributor
timestamp: November 18, 2022, 04:46:49 am
content: I have a device which communicates via RS-232 Port, there are some commands for reading and writing. To make the communication automatic I am using Python(PySerial Library) language, But I am facing a little problem while working, that is, initially everything works fine but after some time I get consistent error of communication failure. I searched a lot on the internet but did not found any relevant solution for that. Programming wise everything is correct from my side, maybe there are some issue with hardware I am not able to figure out.So please help me to make a robust serial communication system.Any SOP(Standard Operating Procedure) regarding serial communication programming would be highly appreciated.PS: I am using USB to RS-232 Cable to connect my RS-232 device and PC.

author: MrAl
author_rank: Super Contributor
timestamp: November 18, 2022, 11:28:34 am
content: Quote from: Md_Aslam on November 18, 2022, 04:46:49 amYou can roll your own RS232 but you'll need to study the protocol first. It is not that complicated though.Some of the USB to RS-232 cables do not work as well as they should that could be the issue. You may have to try a different brand. Make sure they are the type that follow the true specs as some of them only work with a limited output voltage range.

author: BeBuLamar
author_rank: Super Contributor
timestamp: November 18, 2022, 09:02:17 pm
content: Of course there could be problem with the software but as far as hardware wise if you use a USB to RS232 adapter the driver may go to sleep sometimes.
Rocket launcher rough design. - Page 1
Forum section: electronics / beginners

author: perfect_disturbance
author_rank: Regular Contributor
timestamp: May 11, 2013, 01:48:09 am
content: So I'm beginning a design for a launch controller for model rockets. I've developed this (https://www.circuitlab.com/circuit/6u556y/launcherrough/) basic design and wanted input. Mainly about the idea of using a large capacitor to handle the briefly high current demand during launch and using the analog pins to monitor all when the cap is charged enough. Keep in mind this is a rough design. The resistor and capacitor values are just roughly high and low. In comparison to each other. I'll have to calculate actual values to target charging times, acceptable leakage, etc probably based on some testing of the electrical limits of the igniter.

author: jmole
author_rank: Regular Contributor
timestamp: May 11, 2013, 02:11:24 am
content: My advice? Don't use an MCU to trigger a launch. Use a dedicated switch. Keeps the bugs from starting a fire. Don't know if that defeats the point of this, but that's just how I feel.Of course, I remember back in the day, my dad would launch model rockets from the back of his pickup with jumper cables to the battery on the truck. So really, who cares about safety, as long as you're using D or lower class engines.

author: perfect_disturbance
author_rank: Regular Contributor
timestamp: May 11, 2013, 02:29:39 am
content: The micro triggers the launch but (the thgought anyway was) it will only have the voltage/current to launch if sw1 is closed. So here is the basic launch proceedure: turn on the launcher by flipping toggle switch sw3 micro starts and monitors progress changing the state/color of rgb led d2 (yes I know that looks funny but I didn't imediatly see an rgb led in circuit lab so use your imagination). sw1 will be a key switch insert the key and turn it on to start arming the launcher (charging the cap). The micro will monitor the voltage across the cap and not allow launch until the launcher is armed. Then it will change the color of the led. to alert the user it has finished arming and then if you press sw1 it will launch the rocket. The rocket should be considered hot however any time after the key switch has been activaged for the exact reason you stated.
Rogowski coil - Page 1
Forum section: electronics / beginners

author: nForce
author_rank: Frequent Contributor
timestamp: November 24, 2018, 06:41:44 pm
content: I was reading about Rogowski coil on wikipedia:https://en.wikipedia.org/wiki/Rogowski_coilI don't understand under formulae where did this equation came:Doesn't Rogowski coil work from the principle of Faraday's induction law? U = d(psi)/dt?

author: orolo
author_rank: Frequent Contributor
timestamp: November 24, 2018, 08:55:20 pm
content: Yes, using Faraday + Ampère, and being a bit careful couting the number of turns involved.\$ \displaystyle \mathcal{E} \ = \ -\frac{\mathrm{d}\Phi}{\mathrm{d}t} \$The coil has N turns and you can approach the flux by A·B, so:\$ \displaystyle \mathcal{E} \ = \ -N\cdot A\cdot \frac{\mathrm{d}B}{\mathrm{d}t} \$Now use Ampère's law for the current of the wire you are measuring, assuming the wire passes along the centerof the ring and generates a perfectly radial magnetic field. Integrating along the center of the toroid:\$ \oint B \,\mathrm{d}\mathcal{l} \ = \ \mu_0\cdot I\$\$ \mathcal{l} \cdot B \ = \ \mu_0\cdot I \quad \Rightarrow \quad B \ = \ \frac{\mu_0 I}{\mathcal{l}} \$Introduce B into Faraday above, and you get the formula:\$ \displaystyle \mathcal{E} \ = \ -\frac{\mu_0\cdot N\cdot A}{\mathcal{l}} \cdot \frac{\mathrm{d}I}{\mathrm{d}t} \$Edit: added missing `dl´ in the path integral. Spotted by den. Thanks.

author: nForce
author_rank: Frequent Contributor
timestamp: January 19, 2019, 01:38:38 pm
content: I have one other question regarding Rogowski coil:How can we reduce the offset voltage at the integrator circuit? So we measure some voltage, and then we have to integrate to get the current. But how do we reduce the offset voltage before integration?

author: MrAl
author_rank: Super Contributor
timestamp: January 20, 2019, 09:22:14 pm
content: Quote from: nForce on January 19, 2019, 01:38:38 pmHi,Use a low input offset op amp and employ a feedback resistor to reduce DC gain.
Rohde & Schwarz NGRU 35 OVP - Page 1
Forum section: electronics / beginners

author: Ghitza
author_rank: Contributor
timestamp: August 31, 2021, 03:46:50 pm
content: Hi guys,I really need your help, please.I've bought this power supply a month ago. I've used it without problems till today.I cannot set more than 12V in it because the over voltage protection is activated. Sometimes when I power off it and thanpower on again, I can set maximum 15V and without any consumer after 1-2-3-4-5 minutes just goes in OVP.I've tried all the possible combinations of the switches and digital potentiometrs from OVP but absolutelly no change.It works without problems with maximum 12V with stability on voltage and current.What I did last time I used 2 resistors of 4 ohms/ 100w in paralel on it to check the ripple on different currents and voltages.It worked without problems and after I finished I simply turned it off. That was on Sunday and when I powered it on todaythis was the "surprise".Any idea of what could had happened?Thank you very much.
Rohde und Schwarz NGPV power supply! - Page 1
Forum section: electronics / beginners

author: Ghitza
author_rank: Contributor
timestamp: November 13, 2019, 02:09:50 pm
content: Hi guys,I need some help and some info's from you, please.I have 2 power supplies from R&S NGPV (8V/ 10A) and a recovered trafo from a NGPV 20V/ 10A.http://www.mediafire.com/file/tl3zixt9d9n6aci/ngpv.rar/fileIn the upper link there are 6 pics atached in a mediafire link.1- since I didn't found any manual or any kind of documentation for this, tell me please what is the purposeof that "on/ off capacitor" in the first picture and what is the purpose of that "monitoring" option.2- the second power supply is working fine but the only issue is with the fan. It makes a powerfull noise likeis touching something inside. What you recommend me to do for solving this issue? replace the fan with someseparate circuit?3 - in the las pic is the recovered transformer. I've received it exactly like this. Any idea about it's pinout andif I can use it in other application?Thank you very much!
Rokkie Question: what is the differences between thsese 2 layout placement? - Page 1
Forum section: electronics / beginners

author: Jian
author_rank: Newbie
timestamp: October 06, 2024, 09:40:17 pm
content: The rectified signal which go through diode and a cap will goes into LDO, i am kind of wondering what is the different between these two placement of capsschematic as follows,thank you very much for response~

author: PGPG
author_rank: Frequent Contributor
timestamp: October 07, 2024, 12:24:53 am
content: If both C13 and C14 are ceramic capacitors it is not the best idea to connect them paralel because of resonance between their parasitic serial inductances.If C14 is electrolytic capacitor it has bigger ESR (equivalent serial resistance) limiting this resonance quality factor.You should place capacitors in the place to make the circuit in which you consider pulses as small as possible.I suppose that C13 task was to filter out pulses going through D6 so that circuit area should be minimized and C14 task was to be a source for G1 so this circuit area should be minimized.I would probably replaced C13 and C14 with one capacitor or added some impedance between them (like ferryte bead).

author: Ice-Tea
author_rank: Super Contributor
timestamp: October 07, 2024, 08:43:07 am
content: On a somewhat unrelated note: fix your grid. That's an accident waiting to happen.

author: Jian
author_rank: Newbie
timestamp: October 07, 2024, 03:58:37 pm
content: stupied question maybe....schematic grid or pcb gird? im not kind of get it....what accident?

author: Ice-Tea
author_rank: Super Contributor
timestamp: October 07, 2024, 06:23:44 pm
content: Schematic grid. Firstly, it looks unproffesional. Secondly, it takes extra work for get Altium to connect stuff that is off grid. Thirdly, at some point in the future you're going to assume there's a connection on your schematic when there is none. Fourthly: Murphy is an asshole and will, without a doubt, expand on all of the above.
Roland Cube 40 transistor help - Page 1
Forum section: electronics / beginners

author: Supernaut
author_rank: Contributor
timestamp: March 09, 2024, 04:37:06 pm
content: Hoping to get some insight from users on here regarding some components I need to track down for my Roland Cube 40. Im looking for replacements for 2SD667C, 2SD666C and 2SB647C although when i try track down data sheets some don't include the letter "C" at the end of the part number. These components are obsolete so it also suggests some modern equivalents too but I cant find data sheets for my existing parts so I don't know if they compare.Ive tried to include two pictures but they don't seem to show when I click preview post, ,unsure if they will appear.https://pdf1.alldatasheet.com/datasheet-pdf/view/63045/HITACHI/2SD667.htmlhttps://www.alldatasheet.com/view_datasheet.jsp?Searchword=2SD666Chttps://pdf1.alldatasheet.com/datasheet-pdf/view/62848/HITACHI/2SB647A.html

author: Kim Christensen
author_rank: Super Contributor
timestamp: March 09, 2024, 04:53:00 pm
content: The B, C, or D suffix is the transistor Beta range. Otherwise they are the same:

author: CaptDon
author_rank: Super Contributor
timestamp: March 09, 2024, 05:19:41 pm
content: About 5 years back I was able to find exact part number replacements from Toshiba. Carver used similar transistors in the TFM-22 and many other amplifiers. They would develop leakage when they got warm and the idle bias on the outputs would go nuts.

author: Supernaut
author_rank: Contributor
timestamp: March 09, 2024, 06:00:49 pm
content: Thank you both for the replies, Im fairly new to silicon components so sometimes I find it difficult to compare information on data sheets without becoming snow-blind. On some items Ive seen one letter change and the values on the data sheet change drastically so I was uncertain on what to do here.Should hopefully have the amp repaired sometime next week
Role of SCR’s in capacitive discharge high current application  - Page 1
Forum section: electronics / beginners

author: zupta82
author_rank: Regular Contributor
timestamp: January 13, 2021, 05:42:56 pm
content: Hello I was wondering can a scr effect capacitive discharge in high power applications. The application is pulsed high current dc output with a gate drive transformer with a bank of MOSFETS. Also are there some some general basic testing I can perform not live. I already replaced 8 mosfets and 2 fast recovery diodes
Rolling boost auto-transformer from EI transfo (but need to estimate VA) - Page 1
Forum section: electronics / beginners

author: Cliff Matthews
author_rank: Unknown
timestamp: August 20, 2017, 12:58:15 am
content: I was gifted 3 Papst 10-blade 240vac turbine fans that I'm using for ventilation. I ran them on a 240v boost transformer and boy do they move air! But the noise was so bad I decided to insert my Variac to determine 144v will do just fine. My mains is 120v so I concluded I'd need a 24v EI-type transformer to do the boost. The fans are listed as 27-watts each with a DC winding resistance of 240 ohms. I have a 24v at 75VA (3amp) control transformer that I think will give me maximum 432VA as a boost auto transformer.I know the fans won't even use all that, but is (V-line+V-sec * max I-sec) how this calculation is generally done?

author: Zero999
author_rank: Super Contributor
timestamp: August 20, 2017, 08:49:23 am
content: Yes, it's the current rating of the transformer which is important, so your 3A 24V transformer can be used as a 432VA booster.Do you know how much current the fans take? It's likely to be higher than their power rating, because the power factor won't be unity, there again it will be much lower at 144V, than the rated 240V.
Rollmode for logging on Siglent SDS1202X-e - Page 1
Forum section: electronics / beginners

author: Raspy
author_rank: Newbie
timestamp: August 26, 2022, 03:57:01 pm
content: Hello!I have a Siglent SDS1202X-e scope, and am trying to use it to measure storage capacity on some NIMH batteries.To discharge the batterypack i have built a 500mA constant current circuit with a LM317t, that works nice. But i dont want to half to manually check the battery voltage efter 10 minutes, instead i have connected it to my oscilloscope, put it into ROLL MODE with a timefactor of 100s. Optiomally i would like to save 3-4hours of measurements.What happens though is that everytime the line has reached the left end of the screen, the hole things is erased. The same thing happens if i try to use the POSITION wheel to scroll.Does anyone know what i should do to get it to work? I am a total beginner with oscilloscopes, so it might not be a possible thing to do with a scope.

author: tautech
author_rank: Super Contributor
timestamp: August 27, 2022, 06:18:00 am
content: You’d be using auto Roll mode right ?Try dedicated Roll mode accessed by pressing the Roll button below the timebase control.

author: Raspy
author_rank: Newbie
timestamp: August 27, 2022, 04:16:37 pm
content: Yes, i am using the roll mode, but scrolling while in roll mode or when the signal reaches the left side of the screen, erases everything and starts over again.
rom 23C128 TO 27C128 ADAPTER - Page 1
Forum section: electronics / beginners

author: Daxxin
author_rank: Regular Contributor
timestamp: January 13, 2019, 08:06:10 am
content: Any schematic about this adapter?

author: johnkenyon
author_rank: Regular Contributor
timestamp: January 13, 2019, 02:47:39 pm
content: Might be an idea to tell us where/how you are planning to use the adaptor.Note that the chip select/enable(s) on 23C128 were defined active high or low along with the ROM mask, and can have more than one chip select. (For example:http://hardware.speccy.org/datasheet/23c128.pdf)One example is the ZX Spectrum - which effectively had two active low chip selects plus output enable - in this case it is better to mod the PCB to synthesise a nCE signal using a pair of diodes, and use the existing socket. (See:https://spectrumforeveryone.com/technical/fitting-eprom-48k-spectrum/).
Roomba motor Soft Start circuit   - Page 1
Forum section: electronics / beginners

author: Bakafish
author_rank: Contributor
timestamp: September 19, 2017, 11:46:49 am
content: This is my first time posting, so be gentle! Love watching the channel, and will be depending on you guys to help me ramp up my skills.There is a flaw with the 800 series Roomba where the main controller board will randomly kick a small voltage spike into the vacuum motor causing it to click randomly every few minutes 24/7. It is super annoying, like a dripping water faucet. Anyway, some nice individual not only identified the root cause, but he created a "Soft Start" compensation circuit that is supposed to delay the motor spinning up so that these random discharges no longer cause this annoyance. The circuit is quite simple, with one N-type MOSFET, two resistors and a capacitor. I will include his diagram.I built this circuit substituting the MOSFET with an STU13N65M2 n-channel MOSFET (which matched the specifications he said were important), A Panasonic 10uF 50v cap, and nice 1W 100K ohm resistors. The voltage of the motor circuit is 7.2V from NiMH batteries. The MOSFET he used was a BUK663R7-75C, which seems to have a lower Vgs(th) than the one I am using, and I am thinking this may be the problem, but I don't really have much of a clue. Can someone take a look and let me know how to debug this? I have a scope, multimeter and power supply.

author: macboy
author_rank: Super Contributor
timestamp: September 19, 2017, 10:50:50 pm
content: It looks like the run on 14.4 v battery packs. The two 100k resistors in that design effectively form a voltage divider at the MOSFET gate, so the maximum voltage is no more than 7.2 V, assuming the drive signal (grey wire) is at 14.4 V when the motor is on. That is a big assumption. You need over 6 V, more like 7 V to drive the MOSFET into saturation and pass high current, refer to figure 7 in the datasheet, not simply Vgsth. You probably aren't getting that voltage. Reduce R2 by half and/or double R1. This will also change the on/off switching delays, but those aren't critical anyway.

author: Bakafish
author_rank: Contributor
timestamp: September 20, 2017, 07:35:17 am
content: I tried various divider ratio's and kept getting odder and odder output results, then went back and looked at his physical example and realized I didn't understand the mosfet's pinout correctly. After correctly wiring the circuit with the indicated values it works fine. Thanks for taking a look.
rosin flux pen - need to puncture it first? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: May 20, 2017, 01:29:37 am
content: I have this rosin flux pen:http://www.mgchemicals.com/products/prototyping-and-circuit-repair/pens/rosin-flux-835-pRemoving the cap reveals a fibrous tip (which is removable), but it isn't wet.Do I need to puncture the top of the pen body to get the rosin to flow?

author: KE5FX
author_rank: Super Contributor
timestamp: May 20, 2017, 01:39:46 am
content: Push down on a hard surface with the tip to get the rosin action going.

author: ledtester
author_rank: Super Contributor
timestamp: May 20, 2017, 02:27:28 pm
content: Ah - I get it now - it's spring loaded! Thanks!
ROTARY ENCODER interfaced to LED up/down counter module - Page 1
Forum section: electronics / beginners

author: vk5po_John
author_rank: Newbie
timestamp: September 21, 2014, 09:44:13 am
content: Hi from southern Australia guys!Here is my "hopeful application"A Chinese made rotary encoder ( open collector A/B o/puts) attached to a rotating shaft (on a roller inductor in an antenna tuning unit) then interfaced via a LS 7183 QUADRATURE CLOCK CONVERTER IC that in turn ( I was hoping!!!) pulses a "Chinese" LED up / down counter module. (0-9999). The LED counter module "saves" the last known number when powered down, so very handy!This circuit will not work. RBias was set at 10 Mohms, but the pulses appear to be TOO SHORT to register. Another friend suggested sourcing a leading edge type decoder.The counter works a treat when I hit the u/d inputs with a pulse gen.The 7183 must not be suitable for what I was told it would do.The encoder is a 360 pulses per rev. So many applications I could use it on, aside from the one listed above. for instance, a VERY ACCURATE angle indicator as 1 pulse can be seen on a led counter as 1 degree. (for adjusting the elevation of my 50Mhz antennas to point accurately at the moon for bouncing radio waves back to earth.)I have been pulling my hair out for a year or more now, so I would appreciate ANY ADVICE... even another way to achieve what I wish to do.Over to some advice please.Thanks.John

author: max_torque
author_rank: Super Contributor
timestamp: September 21, 2014, 01:39:26 pm
content: Sounds like you need to measure how short a pulse the chinese pulse counter will reliably register, than say add 50%.Then you need a pulse stretcher to modify your "too short" pulses from your encoder i suspect. A bit of a Google around the subject should turn up plenty of circuits to do just that??

author: Precipice
author_rank: Frequent Contributor
timestamp: September 21, 2014, 01:45:14 pm
content: Hang on, are you saying you're pulling up your open collector outputs with 10MOhms? That would severely limit the maximum speed you can run the encoders...

author: German_EE
author_rank: Super Contributor
timestamp: September 21, 2014, 01:55:49 pm
content: The outputs of your encoder are open collector so you need pullup resistors (10K will be OK) from each output to the 5V supply. The Rbias resistor of 10M is a bit high as it is right at the edge of acceptable values so consider changing it to 750K.
Rotary Encoder? What part # and is there a datasheet? - Page 1
Forum section: electronics / beginners

author: monocharismatic
author_rank: Newbie
timestamp: October 10, 2018, 12:20:37 am
content: I've tried to search Google, both regular links and images. I've tried to search through EEVblog forum archives, but couldn't locate anything similar.Does anyone know what this component is? I've retrieved it from a dead MiniDV camcorder, where it was used as a menu selection jog wheel. As you can see from the pictures it has 6 (six) contacts soldered to the PCB and I managed to get continuity between a couple of them with a multi-meter while rotating the wheel one click at a time. But that didn't help me understand how it works as only a couple of contacts responded, the rest a silent.There is also one "leg" (pad/contact) on the other three sides, but they don't seem to be connected anywhere and must be only for helping to secure the component to the PCB, but I may be mistaken.Thank you in advance.
Route് Discovery Table Entries - Page 1
Forum section: electronics / beginners

author: Peili
author_rank: Regular Contributor
timestamp: June 26, 2019, 10:50:32 am
content: Hi !I would like to get something likeroute Discovery tableon LW_MESH 1.2.1 .To be more precise I would like to getLQI and RSSIfrom every node. There are somerouters ,coordinator and End Device.. I would like to get theRoute Discovery Table entries at the ED side. Using the WsnDemo application i would like to get that entries at Application level. Please Help me to solve this.

author: ataradov
author_rank: Super Contributor
timestamp: June 26, 2019, 05:29:40 pm
content: Entries in the real Route Discovery table only exist during the route discovery time. "LQI and RSSI from every node" makes no sense. They only apply to devices in a direct link range. If ED is multiple hops away from some device, then they will not apply to the ED.So you need to clarify what you actually want to get. In any event, those parameters can only be determined if devices send frames, so make all devices send frames to your target device. Each NWK_DataInd_t will have those parameters, so you can collect them in the application.
Router Data Receiving - Page 1
Forum section: electronics / beginners

author: Peili
author_rank: Regular Contributor
timestamp: May 30, 2019, 07:09:19 am
content: Hi,I'm using LWMESH 1.2.1 stack. I have Some End Devices sending data to Coordinator via Router.Data from ED is Unicasting.My application has to modify the data at router side and then route the data to Coordinator.. But at the Router side Nothing is receiving,it just route the packet to Coordinator..I want to receive the Data from End Device to nearest router and then modify the data at router side and then it should route the data..Where i can receive that forwarding packet. Here i'm attaching my code for both Router and ED. WSNDemoRouter.c is Router code and WSNDemoED.c is ED code.. please help me to solve this.

author: Peili
author_rank: Regular Contributor
timestamp: May 30, 2019, 07:12:21 am
content: Another scenario I used wasbroadcasting my data from ED..Then i realized from the document that"When broadcast frame has to be sent, destination MAC address is set to 0xffff (broadcast) and frame is transmitted.Route discovery is not performed for broadcast frames."SO now all the Routers receiving the data from ED and modifying the data packet and also it is routing to Coordinator.I don't want to modify the data by all the routers. It should onlymodified by the nearest Router of EDand all the others should route it to Coordinator.
Router packet Transmission - Page 1
Forum section: electronics / beginners

author: Peili
author_rank: Regular Contributor
timestamp: May 29, 2019, 08:33:02 am
content: Hi,I am using LWMESH 1.2.1 version and have oneCoordinator,some Routers and some End devices.The ED is sending data at every 2sec.I want to create a scenario like routers are placed in a corridor with some distance. ED send data(broadcast,ie, dstAddr=0xffff) and the Router will receive the Data from ED. The router analyze the received data and a decision checking should take place and modifying the data payload and sending the data to Coordinator(0).From the document i understand that, "When broadcast frame has to be sent, destination MAC address is set to 0xffff (broadcast) and frame is transmitted.Route discovery is not performed for broadcast frames."But when i'm using unicast(dstAddr=0) the message are not forwarding.I want an application such ED send data to coordinator via routing. At the router side there is one decision check and after that the data should route.How to do it?

author: soldar
author_rank: Super Contributor
timestamp: May 29, 2019, 03:21:52 pm
content: Maybe a diagram would help. Are we talking Ethernet LAN and IP?
Routing (am I doing it rite) - Page 1
Forum section: electronics / beginners

author: Ferroto
author_rank: Frequent Contributor
timestamp: April 26, 2010, 12:02:07 pm
content: I'm making an RC car. The motors will be suspended by a piece of wire that's going to be soldered through vias that I haven't created yet. It's still a work in progress, but in the end it'll have two tracks, and be controlled wirelessly.Also to show my awesomeness, I made the entire thing on one side of the PCB with no jumper wires

author: DavidDLC
author_rank: Frequent Contributor
timestamp: April 26, 2010, 04:16:13 pm
content: If you are not planning to use an IC socket for the PIC controller, then it will be a good idea to include the ICSP connections to modify the firmware.BR.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: April 26, 2010, 04:21:26 pm
content: mmm seems like the connector marked as "Controls" could be the ICSP, if that is the case I will change the Label to ICSP.Let us know.

author: RoelA
author_rank: Contributor
timestamp: April 26, 2010, 05:00:57 pm
content: How are you going to control your motors? An PIC can only supply a limited current before everything blows up. Normally, you shouldn't draw more then 15-20 mA per pin.And you still have a 90 degree bend above your pic, you should make a 45 degree turns there too.

author: TheDirty
author_rank: Frequent Contributor
timestamp: April 26, 2010, 07:50:08 pm
content: Try to connect to the pads at the ends rather than cutting into them at an angle. You might want to increase the 'isolate' value on your polygon as well. I try to keep it around 12 or 16 mils. Is C2 thru C4 input filtering? Move the caps closer to the PIC.

author: mkissin
author_rank: Regular Contributor
timestamp: April 26, 2010, 08:47:27 pm
content: Just to add to what the others have already mentioned, I always try to avoid routing traces underneath ICs. It's not the worst thing with DIP packages, but it will mean you get an unbroken ground plane under it.You could try bringing the track that connector to pin 4 of the PIC out and going around to the left of the controls connector, or perhaps change the pins entirely so that they route more neatly (that may not be possible depending on what the connector is for).

author: TheDirty
author_rank: Frequent Contributor
timestamp: April 26, 2010, 09:13:30 pm
content: Are you etching this yourself? I just thought that might be why you are trying to keep this single sided. If you are etching this yourself, you'll want the traces and mask on the bottom side rather than the top.

author: Ferroto
author_rank: Frequent Contributor
timestamp: April 27, 2010, 01:22:29 am
content: Quote from: DavidDLC on April 26, 2010, 04:21:26 pmThe controls header controls the motors, and can go into reverse by reversing the polarity.The signal is fed to a motor driver board that is the same dimensions as the RC_Control_Module and mounted below it by the vias on top and bottom.The finished product will be 3 wafers stacked. The board you're looking at is the middle wafer. the bottom has the motor drivers and the motors attached, and the top is the transmitter.
Routing the light from small SM LED's to a case - Page 1
Forum section: electronics / beginners

author: FearTec
author_rank: Regular Contributor
timestamp: April 17, 2016, 01:53:11 pm
content: HelloI would like to route the light from about 6 small LED's on a few boards (in this projecthttps://www.eevblog.com/forum/beginners/raspberry-pi-running-from-batteries-and-solar/) to a single area on a proto box. I have some plastic j shaped bits from an old router that bent the light to the top of a router but it wont work on my box (wrong shape).Is there such thing a fibre optic or flexible/shapable plastic that I can use to flexibly capture the light from 5 lights on the raspberry pi and wifi and route the light to an ordered panel?Thanks In advance.

author: uncle_bob
author_rank: Unknown
timestamp: April 17, 2016, 03:26:50 pm
content: HiThe most practical way to do this is with clear plastic rod. It comes in a variety of diameters and you can warm it up to bend it. Plexiglass is one fairly common material to use. There are others. The heat involved is not terribly high. More than most hair dryers, less than a stove burner set to full blast.Bob

author: Ice-Tea
author_rank: Super Contributor
timestamp: April 17, 2016, 04:02:02 pm
content: Think you're looking for something like this:http://www.mentor-bauelemente.de/de/bauelemente/ll-lichtleiter-vom-spezialisten/

author: madires
author_rank: Super Contributor
timestamp: April 17, 2016, 04:25:07 pm
content: Quote from: uncle_bob on April 17, 2016, 03:26:50 pmI'm using a hot air station to bend different thermoplastics. Works great.

author: max_torque
author_rank: Super Contributor
timestamp: April 17, 2016, 07:45:51 pm
content: Google for "Light pipes" Lots available, including flexible ones!i.e.

author: FearTec
author_rank: Regular Contributor
timestamp: April 18, 2016, 08:45:43 am
content: Thanks champs

author: Jeroen3
author_rank: Super Contributor
timestamp: April 18, 2016, 08:51:29 am
content: If you use bottom entry LED's you can glue in a piece of PMMA cable.One thing though, it seems like eBay only sells it on full >100m spools.
Routing tips? - Page 1
Forum section: electronics / beginners

author: s3c
author_rank: Contributor
timestamp: July 03, 2010, 09:48:40 pm
content: The EMC course I did had a short section about routing considerations, one thing that wasn't mentioned was the difference curved versus 45 deg lines make, can anyone provide some insight as well as any other random suggestions?

author: EEVblog
author_rank: Unknown
timestamp: July 03, 2010, 10:48:31 pm
content: Quote from: s3c on July 03, 2010, 09:48:40 pmThat's because it's essentially a myth, in all but the most extreme circumstances.One key is to keep your loop areas as small as possible.Dave.

author: jahonen
author_rank: Super Contributor
timestamp: July 04, 2010, 05:54:54 am
content: I would add that the loop area must be considered in 3D-fashion, including component leads and connectors/sockets (Mr. Maxwell sees it in this way in the final product!). This is often forgotten since layouts are usually examined as 2D drawings and Z-axis is not visible.Another one is that use source terminated transmission lines (series resistor at source end, contiguous ground plane below the trace, and trace width at least in same order than dielectric thickness, gives you ~75 ohms traces, double trace width gives 50 ohm traces) instead of just random p2p-traces. This won't hurt in EMC sense (even if you wouldn't actually need it), but might cost you more layers to your PCB (step from 2 to 4 is usually the most painful!).Regards,Janne

author: RayJones
author_rank: Frequent Contributor
timestamp: July 06, 2010, 09:48:24 pm
content: This reminds me of an addon, WAYYYYY BACk, you could get for Protel.Smartarcs.Yes, the name could get you in trouble.
Routing USB Between PCBs - Page 1
Forum section: electronics / beginners

author: braddrew0
author_rank: Regular Contributor
timestamp: October 13, 2019, 09:55:13 am
content: Hey All,I need to route a USB signal between two PCBs. The rough flow looks like USB port > board 1 > some plug > cable > some plug > board two > USB PHY. I'm planning to use standard 5 core USB cable for the cable, but I'm coming up short trying to find a suitable plug. Has anyone had to do this before, and/or can recommend something that might work? The signal is up to USB HS (480 MBps) - and yes, I understand this is probably well outside USB spec (although if there was an in spec answer that isn't using a hub/standard USB cable between the two) I'd be interested to hear.Thanks!

author: sokoloff
author_rank: Super Contributor
timestamp: October 13, 2019, 09:58:35 am
content: They come off millions of desktop motherboards worldwide on DuPont style headers, right?

author: tooki
author_rank: Super Contributor
timestamp: October 13, 2019, 10:35:04 am
content: Quote from: braddrew0 on October 13, 2019, 09:55:13 amWhynotuse a standard cable, e.g. micro USB?But as sokoloff said, you can just use any old headers for the connectors. While the cable itself really should be USB cable*, the connectors aren’t critical.*Internal USB is routed through PCB traces and all kinds of cables. For low-speed USB it probably isn’t critical at all. For full-speed and high-speed, chances are the design of the traces or cables matters, so it’s easier to just buy USB cable rather than to learn and try to implement the specs.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 13, 2019, 10:58:25 am
content: What do you mean by "two PCBs", are they stacked boards in an assembly? Different PCBs inside a common enclosure? Completely separate projects?In the first case, plain headers are fine, even for high speed.In the second case, the aforementioned Dupont style (or Molex SL, or...) is fine; a shielded cable is greatly preferred, but the shield termination into the connector probably doesn't need to betootight.In the third case, fully shielded connectors and cable should be used.Note that hybrid cases are common: a PC might have #2's solution from the motherboard to a front panel connector (which is grounded to the metal chassis), then #3's solution to the outside world (regular USB cables and devices). The key is having ground planes available for shielding. (The assumption in #1's solution, is that the boards are both ground plane based designs, and the headers have multiple ground pins to ensure those grounds are well bonded through the connector.)Tim

author: braddrew0
author_rank: Regular Contributor
timestamp: October 14, 2019, 07:00:42 pm
content: Thanks guys!