Recent Posts

91

Test Equipment / Re: Siglent SDS3000X HD and upgraded SDS1000X HD

« Last post by DaneLaw on Today at 02:30:22 am »

24h later.....
Unpacked, more pictures will follow in the days to come.
The fact that the display foil is not present and neither are the front dust caps is not a problem, but it was different with the 2104XHD.

As it turned out today, I wouldn't have been able to get one either, despite ordering over 3 months ago.
They sent me their own demonstration device by mistake (hence the missing display foil and dust caps), but I can keep it until a new one is actually sent out.

This Batronix "mistake" where they seem to ship you their own demo-unit as your new retail unit..
Was it you, that asked Batronix why your SDS3000X HD were missing certain new clothing factors, like screen-foil etc, and then they explained you, that "ups we made a mistake  and shipped you our demo unit" or was it Batronix that gave that info without any inquiry and we made a mistake and its only a temporary and you will get a brand new model when its in stock?

92

Manufacturing & Assembly / Re: LPKF Protomat S42: Machine "shock absorber"/"stroke limiter" tuning

« Last post by rsaxvc on Today at 02:27:27 am »

I think I found it! Stashed away in a different bit-box, there was one unmarked drill bit with a pink ring around it, 43mm long, 2.95mm diameter. The reference strips are 4.5mm thick, the reference strip slot is 5mm deep past the bed surface, so if a 38mm bit is almost touching the bed, a 43mm bit would leave at least .5mm clearance from the bottom of the slot, without adjusting the Z-stage-limiter. I've also found a short piece of old reference strip with a hole in it! What a find! A short bit of plastic! But the hole in there is ~3.4mm deep, and when I drilled with the 43mm bit, I got a ~3.3mm deep hole that matches the reference pin well. I think I'm all set. Thanks!

93

Beginners / Re: LM317 Based Digitally Controlled Power Supply

« Last post by EthannCraftt on Today at 02:25:23 am »

Thanks all for replying!! I got caught up in my high voltage work and was a little busy with that.

I'm not necessarily opposed to replacing the lm317 with discrete components, I just thought it would be a fun design challenge and a nice way to use the ones I had on hand

I did plan on adding a feedback on the output to the microcontroller (and one across the 1ohm resistor from the current limiter circuit), I just didn't know how to integrate that into a digital schematic.

The main problem that I've noticed based on the replies was the fact that inputing a voltage puts the internal voltage refrence in series, and to be frank I doubt the accuracy of my own voltage input. How would I go about voltage regulation with PWM another way that doesn't have this issue? I couldn't figure it out with my tinkering in simulation software. Can it even be done while maintaining use of the LM317?

Again, I would be perfectly okay with changing out the voltage regulator with discrete circuitry, so long as it's accurate(ish). Thanks!

94

Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement

« Last post by BrianHG on Today at 02:22:16 am »

Hi, are you saing my current PC74hct4046ap is a little less noise than 74HC4046? If so is the SN74LV4046AN even less noisy?   

HC4046 should be a little less noisy.
LV4046 isn't designed for 5v supply, it's designed for 3.3v supply and below.  (Don't quote me here, double check the data sheet.)

95

Microcontrollers / Re: Routines to convert binary to BCD in C code

« Last post by Nominal Animal on Today at 02:15:52 am »

Is there an actual problem that's trying to be solved here?

Not really.  Binary to decimal conversion is considered "slow" and requiring "surprisingly much" machine-level code, compared to arithmetic operations, so these can be useful in some cases, but that's about it.

Library implementations, especially various printf() implementations, are written for correctness and not for efficiency, so when you work with smaller microcontrollers, especially 8-bit ones (AVRs, PICs, 8051s), a custom implementation can be useful.  More annoyingly, most standard library functions use arbitrary precision arithmetic and dynamic memory allocation during conversion of floating-point numbers.

Even on fully hosted C environments, it turns out that if you read numeric data from text files, the standard C library string-to-number conversions (strtod(), strtol(), scanf() and their variants) become the bottleneck, when you have enough (megabytes) of data.  Then, too, "optimized" conversion functions can reduce the load times to a fraction of what they would be using standard C conversion functions.

96

RF, Microwave, Ham Radio / Re: WSJT-X on Pi

« Last post by tatel on Today at 02:10:21 am »

Glad you achieved it. Enjoy.

97

Beginners / Re: Replacing SRAM IC with Flash

« Last post by Nominal Animal on Today at 02:05:13 am »

I noticed LCSC and JLCPCB do not have many parallel SRAM IC's in stock; currently only 7 different models, of which only two are suitable, and cost 30€+.  Ouch.

I thought of pulldown the 4 pins to have initial address bank of 0

Sure.

please check attached initial rough drawing for the whole suggested system.

Displaying the bank number in anything except binary is a bit of a chore.  CD4511 and similar can do 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 using 7 LEDs (7-segment display) based on the four address lines, but would be blank for the last five.  Decoders like 74'138D can decode three address lines into 8 LEDs, so you'd need two of those, and one logic inverter (for the extra bit, a single MOSFET will do).

Hmmm....

The access time of the Sharp LH52256C/CH is 70ns, which corresponds to slightly over 9 clock cycles at 133 MHz.  It seems to me you might be able to use an RP2040 (C2040 at LCSC, about 1€ at LCSC and JLCPCB) to emulate parallel SRAM using PIO via (15+8+3) 26 I/O pins, two pins for I2C (128×32 OLED display), and two pins for buttons – perhaps an I2C slave, shift register, or something.  See various "PicoRAM" projects.

The 26 I/O pins do need (unidirectional) level shifting between 5V (N64) and 3.3V (RP2040) – perhaps four 74LVC4245APW,118 (C6091 at LCSC).

RP2040 uses an external QSPI Flash chip, up to 16 MBytes (Winbond W25Q128JVS is used in examples, C97521 at LCSC; minimum 100,000 erase cycles); some of this would be reserved for code and bootloader, but we're talking a three to five hundred "banks", easy.  And since it has an USB connection, you could transfer the saved states to/from a computer, each 32k long and corresponding to a separate Pak.

The Hardware Design with RP2040 includes a minimal example.  The power section would differ in that you'd use two diodes or a dual common-cathode diode in front of the 3.3V regulator, to select between USB and N64 5V sources.  (Some '1117 series regulators fail short circuit, so I'd suggest carefully selecting which one to use.)  The level translators would be powered from the N64 5V.  You also need a 12 MHz crystal (Abracon ABM8-272-T3, C20625731 at LCSC).  The USB D+ and D- lines need 27.4Ω resistors in series, between RP2040 and the USB connector.  So, in addition to the minimal example schematic (page 25), we'd need the voltage translators, I2C pull-up resistors (two 2.2kΩ, or at least pads for two 0603 resistors), and say a TI TCA6408A (C181499 at LCSC) or TCA9555PWR (C465732 at LCSC) as an I2C expander, providing 8 or 16 additional I/O pins that you could use for buttons or LEDs.

Essentially, the RP2040 would keep a single Pak (32kbytes of RAM) in memory as long as it was powered on, but whenever a button is pressed, copy it to Flash.  (Another option would be to use another PIO to observe the /WR pin, to auto-trigger a save a half a second to second after the last write.)
Additional buttons would be used to select which Pak is currently active.  Since there are so many Paks to choose from, you probably want at least three buttons (next, previous, select), but note that additional modes like "read-only Pak, changes not saved to Flash" and auto-allocating a Pak to a new slot whenever changed, would be easy to implement in software, so at least one more button to select between configuration and Pak is needed.  So, say five buttons.  A TCA6408A provides eight additional I/O pins, perfect for buttons.

going MCU is a no-go for me since i won't be getting the production boards here to my country (Jordan) due to excessive customs charging and the complicated stuff I need to do. All my other products which are being sold now come from PCBway directly to my shipment and fulfillment company (Next Smart Ship) which is linked to my store... then I ship with press of a button.

Ah, okay.

how much bom cost do you expect after this?

I'd expect under 10€ in any case, but that assumes you could get the SRAM chip at Mouser prices (~ 6€ or less) somehow.

98

Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement

« Last post by dj_holmes on Today at 01:53:42 am »

Hi, are you saing my current PC74hct4046ap is a little less noise than 74HC4046? If so is the SN74LV4046AN even less noisy?   

99

Manufacturing & Assembly / Re: LPKF Protomat S42: Machine "shock absorber"/"stroke limiter" tuning

« Last post by rsaxvc on Today at 01:53:31 am »

I'm afraid I may not have explained my challenge accurately enough. I'm trying to drill reference holes in the plastic strips the non-camera S42 uses for PCB registration. Once I'm able to do so, I should be able to install a pair of reference pins in the strips, then fit PCB with corresponding holds over the pins, mill one side of a PCB, flip it, and mill the other, then drill and slip a bit of wire through, solder on both ends.

The bit for drilling the reference specified in the manual and software, as a 2.95mm drilling bit I couldn't find on LPKF's website. My machine came with two 38mm 2.95mm drill bits, but they're short enough that the Z-stroke-limiter just barely prevents contact with the bed or reference strips.

You've got me thinking that a longer 2.95mm drill bit is probably what the machine originally came with from LPKF, and I'd like to replace it, but I'd need to know the length required for the right depth. Too shallow and the pins are likely to loosen prematurely, too deep and it might drill fully through the reference strip into the aluminum bed.

I've attached a photo of my machine that I hope shows this better.

100

Power/Renewable Energy/EV's / Re: Why are all Vicor PI3 modules suddenly out of stock or obsolete?

« Last post by jbb on Today at 01:50:06 am »

It’s a long shot, but could be clerical error at Digikey end. Suggest you cross your fingers and check with Victor directly.