Author Topic: Components you wish existed.  (Read 60453 times)

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Offline Richard Crowley

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Re: Components you wish existed.
« Reply #150 on: May 27, 2017, 07:06:38 am »
Replacement for LM3915/3916  Might be able to identify a tiny microcontroller that could be programmed to almost provide the same functionality(?)
 

Online Kjelt

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Re: Components you wish existed.
« Reply #151 on: May 27, 2017, 07:17:44 am »
Quote
A MCU with integrated RS485 PHY
The ST Uarts do have a RS485 data enable signal but the driver it self is always extern. Because RS485 is often used in long distances and industrial environments it is not uncommon to see in industrial device this driver as a dip package in a socket so with damage it can be replaced.
 

Offline ali_asadzadeh

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Re: Components you wish existed.
« Reply #152 on: May 27, 2017, 08:36:16 am »
technix
Thanks, but did you even read it carefully? STM32F373 it's not bipolar input!

Quote
I have never heard of this.
it's a wish list and I'm sure you never heard of it,

Quote
WCH CH563
Can we see the datasheet in English?

Quote
Cyclone IV?
Not affordable enough.

Quote
3D printing.
a plastic  injection is far superior to 3D printing rubbish ;)

Quote
Ditto for display modules.
what's Ditto? do you have a link? we need image sensors with real datasheet and availability
ASiDesigner, Stands for Application specific intelligent devices
I'm a Digital Expert from 8-bits to 64-bits
 

Offline SeanB

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Re: Components you wish existed.
« Reply #153 on: May 27, 2017, 09:52:39 am »
Large-value (~10 uF) *medium* ESR ceramic capacitors. Most existing ones have frustratingly low ESR for bypassing applications.

Not if your control loop is properly designed. There are tons of LDO/SMPS controllers that can operate at nearly zero ESR, as long as they're designed properly.

What's that got to do with the price of fish? There are plenty of places one needs some bypassing (with the damping of moderate ESR) that are nowhere near a PSU or its control loop, or a control loop of any kind.

simply put a space for a zero ohm or whatever desired ESR value SMD resistor in series with the capacitor. Instant controllable ESR and also a test point, just costs a single resistor.
 

Offline David Hess

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Re: Components you wish existed.
« Reply #154 on: May 27, 2017, 12:33:18 pm »
A MCU with integrated true bipolar ADC inputs, say +-10V and 16Bit plus and 500KSPS+ of course single supply device say 3.3V

That kind of resolution in a sampling ADC conflicts with having a noisy microcontroller in the same package.

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A MCU with integrated RS485 PHY, with integrated  CAN PHY

It is less expensive to have a separate PHY because the most economical IC processes for microcontrollers do not support the interface voltages required.

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A MCU with integrated Audio Codec

I thought they have these but I guess not.  Still, lots of microcontrollers can directly interface with cheap external audio codecs.

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An ARM Cortex A with integrated  DRAM (more than 1GB) and from a know good brand not bullishit parts from Allwinner with out the real good support

Because high density DRAM processes are specialized, it is more economical to include the DRAM as a separate die in the same package like with the Raspberry Pi processor.
 
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Offline technix

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Re: Components you wish existed.
« Reply #155 on: May 27, 2017, 03:28:16 pm »
technix
Thanks, but did you even read it carefully? STM32F373 it's not bipolar input!
I know. Sore point. Ouch.
Quote
I have never heard of this.
it's a wish list and I'm sure you never heard of it,
You get me.
Quote
WCH CH563
Can we see the datasheet in English?
I don't think they have one. If you need one I can ccok one up for you, but allow me to first cook up a board and give it a jog (I do have samples but not eval kits.)
Quote
Cyclone IV?
Not affordable enough.
Sadly. Maybe a Cyclone IV coupled to a STM32F103VE/Allwinner V3s?
Quote
3D printing.
a plastic  injection is far superior to 3D printing rubbish ;)
Making the mold costs a crazy lot of $$$. For one-off products you are more likely than not stuck to CNC and 3D printing.
Quote
Ditto for display modules.
what's Ditto? do you have a link? we need image sensors with real datasheet and availability
I mean that display module manufacturers have the same nasty habit of keeping their products shrouded in NDA. A lot of nice chips suffer from the same NDA problem (I am looking at you sir, ATECC508A.)
 

Offline helius

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Re: Components you wish existed.
« Reply #156 on: May 27, 2017, 04:01:42 pm »
a plastic  injection is far superior to 3D printing rubbish ;)
Making the mold costs a crazy lot of $$$. For one-off products you are more likely than not stuck to CNC and 3D printing.
You can sometimes 3d-print a mold when using spin casting. See http://www.stratasys.com/solutions/additive-manufacturing/tooling/spin-casting
It is not quite as flexible as injection molding but much cheaper.
 

Online BrianHG

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Re: Components you wish existed.
« Reply #157 on: May 28, 2017, 03:17:53 am »
A MCU with integrated RS485 PHY, with integrated  CAN PHY

I used a PIC with comparitor inputs with series & termination resistors to protect the IOs from surge.  When in input mode, the 2 comparitor inputs act as a true authentic differential receiver, then to transmit, I switch the 2 comparitor inputs to outputs to create a differential line driver with microchip's +/-50ma per pin output drive.  Of course, I had to use a software serializer/de-serializer, but, with this, I had an 8 story apartment building with 20 shared addressable nodes temperature sensor/light control/alarm buttons running on phone wires at 19200 baud error free.
 

Offline jonovid

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Re: Components you wish existed.
« Reply #158 on: July 05, 2017, 11:18:44 am »
convex OLED video screens for retro or reproduction video arcade machines.
the need for a 29” CRT Monitor emulator using convex 25"  - 29” OLED 800 x 600 video screen.
the OLED retro video screen needs to have the look and feel of a convex CRT Monitor without the weight or 1980s power consumption.

original CRT Monitor is preferred in a true reproduction of a arcade machine.

« Last Edit: July 05, 2017, 03:24:48 pm by jonovid »
Hobbyist with a basic knowledge of electronics
 

Offline coppice

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Re: Components you wish existed.
« Reply #159 on: July 05, 2017, 01:43:06 pm »
Electrolytic Capacitors (i.e. low cost, relatively high capacitance value) which DON'T leak and/or significantly deteriorate, over a large number of years.

Tantalum and aluminum capacitors with solid polymer electrolyte are available. Well known types include Sanyo OS-CON and others.

Solid polymer electrolytic capacitors have their own wearout mechanism; the polymer degrades following the usual Arrhenius equation halving their operating lifetime for every 10C temperature rise.  Their big advantage is lower ESR yielding lower power dissipation and operating temperature.
Most motherboards using solid aluminium capacitors claim an operating life of 50k to 100k hours (5 to 10 years). I don't know what temperatures they are basing those estimates on. They don't seem to say.

When we first started using Philips solid aluminium caps for telecoms equipment, in the 80s, we were building for a minimum life of 15 years continuous operation with only passive cooling. Things could get pretty warm in some telephone exchanges.
The closest thing to an electrolytic capacitor which does not wear out is a solid or wet tantalum capacitor (1) but these have their own issues and high price.  In practice an almost arbitrarily long operating life can be gained using normal aluminum electrolytic or polymer electrolytic capacitors with suitable derating.

(1) And niobium oxide capacitors?
Tantalums have a long overall life, but both solid and wet ones are subject to occasional whisker shorts. With a beefy power supply these will self correct. With a very low capacity supply they may form a permanent short. Either way, they can make a telephone exchange crash, and were in fact found to be the main cause of such crashes. We first adopted solid aluminiums to avoid our exchange equipment hiccuping like that, and it did seem to be an effective cure.
 
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Offline mariush

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Re: Components you wish existed.
« Reply #160 on: July 05, 2017, 02:45:31 pm »
There's a different formula used to approximate life of polymer capacitors.  Can't use the electrolytic formula (double life for every 10c less)

Here's a link : http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx

Polymer caps:



Radial/SMD electrolytic  (but like i said, you can simplify it to double life every 10c decrease):



 
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Offline technix

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Re: Components you wish existed.
« Reply #161 on: July 07, 2017, 02:40:06 am »
I'd like to see a Zynq in a stacked RAM package.
Seconded. Accepting PoP packages or embedding chips as MCM isn't that hard, and thermals can be managed by embedding the RAM dies in the same way as those GPU chips with HBM memory.
 

Offline RobK_NL

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Re: Components you wish existed.
« Reply #162 on: July 07, 2017, 02:26:11 pm »
4. CdS cells - Is there really a problem with hermetically sealed CdS?
Plenty of them available
All the "NSL" types are hermetically sealed.
Tell us what problem you want to solve, not what solution you're having problems with
 

Offline GarthyD

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Re: Components you wish existed.
« Reply #163 on: July 09, 2017, 02:57:19 am »
A few rambling thoughts:

- A runtime-reconfigurable CPLD. It starts up with the image last flashed via a dedicated programming connection (say, JTAG) to its internal flash. Groups of pins and cells can be locked into fixed configurations via security bits in the flash. It is through this initial image and a non-programming connection that you reconfigure the remaining cells (say, via SPI). The locking protects the runtime changes from being destructive, such as outputting on a pin that on your board goes to another output. Specification is open enough that you don't need a specialised tool to make these runtime changes.

- A conductor/insulator/conductor "sandwich" with a module coming out of the side that you could attach two jumper wires to. To use, you desolder an IC lead from its pad, insert the "sandwich", resolder, and now you can insert something in series between the IC lead and the pad (eg. to measure current). Bonus points if it comes with a tiny DIP switch that you can switch to keep it connected when not in use.

- Readily available extremely short 2.54mm female/female headers to adapt male headers/jumpers to male headers/jumpers, as well as allowing you to adapt a through-hole component to a male header pin where distance matters (eg. crystal, cap on a breakout board).

- A Surface mount 2.54mm male/female header that is insulated underneath, with a small side tab that you could solder to an existing populated SMT pad on a PCB, to add jumper-wire-friendly connection to a prototype PCB that you left out. I have no idea how you'd secure it for disconnections though.

- Minimal through-hole breakouts customised for each MCU produced with space to put caps and crystals optimally as standard. The design is released so anyone can make them. Purchasable assembled and unassembled.

- Some of the more interesting battery charger plus voltage regulator ICs with proper leads rather than being mostly leadless.

- Fully-assembled boost converter module as a through-hole component with no layout requirements. Five pins: In, out, ground, enable, and a resistor to set voltage.

- Small breadboard with no valley so that you can plug a two row 2.54mm connector directly into the middle via male headers and have connections heading outward from each individual pin.

- A breadboard that can grasp short pins.

- Jumper wire with small (eg. 22 ohm) series resistors located near either one or both ends.

- A small inexpensive reprogrammable eight-pin device that does nothing but apply a lookup table to a fixed number of input pins to produce output for a fixed number of output pins. Pins might be VCC, GND, three inputs, two outputs, programming pin. Like a small primitive CPLD.

- Power-pooling IC that accepts a few power sources and outputs uninterrupted power even as the sources are connected and disconnected. One source assumes a single-cell Li-Po and minimises the voltage drop. The battery source is isolated if the other sources are providing power. An output pin indicates if we are running from battery or not.

- An external power detect/LED IC for projects that use a battery. Overvoltage-protected input detects external power. Output (eg. to MCU) to indicate when external power is detected. Open drain output to connect to a LED. Input (eg. from MCU) that overrides the LED output, either on or off. IC is ultra-low-power when LED off and no external power.

- Shift register where every two bits controls what is connected to one pin: Either nothing, a weak pullup, or a weak pulldown.

- Inexpensive through-hole P-channel MOSFETS (if it's 6c for SOT-23, why am I paying $1.60 for something comparable through-hole?).

- A micro USB B connector with long leads for hand-soldering that is actually sold anywhere.

- Small SMT crystals with leads or at the very least hand-solderable pads on the side of decent size.

- A small surface-mount component (0603 or much smaller) that conducts as shipped but you can deliberately break the connection with a small tool, magnifier, and steady hand. Essentially a tiny dip switch with default on.

- A module that you can solder on to standard footprints that contains an upper module with the same footprint but with longer pads. ;)

- An adapter that has 2.54mm male header pins on one side (say, 2x5) and individually spring-loaded pins on the other that will make contact with a wide range of PCB hole sizes. The header pins then go to a cable. For testing before soldering real headers on.

- Jumper wire with one end having some kind of connector that lets you make secure, but temporary connections with a plated through-hole of various sizes *vertically* at most points on a PCB.

That was actually quite fun to write up. :) I'm sure quite a few of these exist already.
 

Offline technix

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Re: Components you wish existed.
« Reply #164 on: July 09, 2017, 03:59:40 am »
A few rambling thoughts:

- A runtime-reconfigurable CPLD. It starts up with the image last flashed via a dedicated programming connection (say, JTAG) to its internal flash. Groups of pins and cells can be locked into fixed configurations via security bits in the flash. It is through this initial image and a non-programming connection that you reconfigure the remaining cells (say, via SPI). The locking protects the runtime changes from being destructive, such as outputting on a pin that on your board goes to another output. Specification is open enough that you don't need a specialised tool to make these runtime changes.

- A conductor/insulator/conductor "sandwich" with a module coming out of the side that you could attach two jumper wires to. To use, you desolder an IC lead from its pad, insert the "sandwich", resolder, and now you can insert something in series between the IC lead and the pad (eg. to measure current). Bonus points if it comes with a tiny DIP switch that you can switch to keep it connected when not in use.

- Readily available extremely short 2.54mm female/female headers to adapt male headers/jumpers to male headers/jumpers, as well as allowing you to adapt a through-hole component to a male header pin where distance matters (eg. crystal, cap on a breakout board).

- A Surface mount 2.54mm male/female header that is insulated underneath, with a small side tab that you could solder to an existing populated SMT pad on a PCB, to add jumper-wire-friendly connection to a prototype PCB that you left out. I have no idea how you'd secure it for disconnections though.

- Minimal through-hole breakouts customised for each MCU produced with space to put caps and crystals optimally as standard. The design is released so anyone can make them. Purchasable assembled and unassembled.

- Some of the more interesting battery charger plus voltage regulator ICs with proper leads rather than being mostly leadless.

- Fully-assembled boost converter module as a through-hole component with no layout requirements. Five pins: In, out, ground, enable, and a resistor to set voltage.

- Small breadboard with no valley so that you can plug a two row 2.54mm connector directly into the middle via male headers and have connections heading outward from each individual pin.

- A breadboard that can grasp short pins.

- Jumper wire with small (eg. 22 ohm) series resistors located near either one or both ends.

- A small inexpensive reprogrammable eight-pin device that does nothing but apply a lookup table to a fixed number of input pins to produce output for a fixed number of output pins. Pins might be VCC, GND, three inputs, two outputs, programming pin. Like a small primitive CPLD.

- Power-pooling IC that accepts a few power sources and outputs uninterrupted power even as the sources are connected and disconnected. One source assumes a single-cell Li-Po and minimises the voltage drop. The battery source is isolated if the other sources are providing power. An output pin indicates if we are running from battery or not.

- An external power detect/LED IC for projects that use a battery. Overvoltage-protected input detects external power. Output (eg. to MCU) to indicate when external power is detected. Open drain output to connect to a LED. Input (eg. from MCU) that overrides the LED output, either on or off. IC is ultra-low-power when LED off and no external power.

- Shift register where every two bits controls what is connected to one pin: Either nothing, a weak pullup, or a weak pulldown.

- Inexpensive through-hole P-channel MOSFETS (if it's 6c for SOT-23, why am I paying $1.60 for something comparable through-hole?).

- A micro USB B connector with long leads for hand-soldering that is actually sold anywhere.

- Small SMT crystals with leads or at the very least hand-solderable pads on the side of decent size.

- A small surface-mount component (0603 or much smaller) that conducts as shipped but you can deliberately break the connection with a small tool, magnifier, and steady hand. Essentially a tiny dip switch with default on.

- A module that you can solder on to standard footprints that contains an upper module with the same footprint but with longer pads. ;)

- An adapter that has 2.54mm male header pins on one side (say, 2x5) and individually spring-loaded pins on the other that will make contact with a wide range of PCB hole sizes. The header pins then go to a cable. For testing before soldering real headers on.

- Jumper wire with one end having some kind of connector that lets you make secure, but temporary connections with a plated through-hole of various sizes *vertically* at most points on a PCB.

That was actually quite fun to write up. :) I'm sure quite a few of these exist already.
I wonder if the MCP23S17 counts as a shift register with pin I/O controls? It is effectively two PIC16 parallel I/O blocks hooked to a SPI bus.
 
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Offline bjcuizon

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Re: Components you wish existed.
« Reply #165 on: July 09, 2017, 04:39:59 am »
An 0805 smd resistor with 2W power handling and an electrolytic cap that doesn't die in any way possible.
Don't mess with an Electronics Engineer, it Megahertz!
 

Offline technix

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Re: Components you wish existed.
« Reply #166 on: July 09, 2017, 04:56:30 am »
An 0805 smd resistor with 2W power handling and an electrolytic cap that doesn't die in any way possible.
Just add heatsinks.
 

Offline GarthyD

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Re: Components you wish existed.
« Reply #167 on: July 09, 2017, 05:25:58 am »
- Shift register where every two bits controls what is connected to one pin: Either nothing, a weak pullup, or a weak pulldown.
I wonder if the MCP23S17 counts as a shift register with pin I/O controls? It is effectively two PIC16 parallel I/O blocks hooked to a SPI bus.

Thanks for the suggestion. A GPIO expander would certainly solve the same problems, and the MCP23S17 certainly covers the pull-up side of the equation. Or, use the outputs and add a suitable resistor and use it to pull in either direction.

I think my ideal component in this case would be one that just had configurable pull-ups and pull-downs and had a price to match. Something simpler and cheaper than a full GPIO expander but a bit more flexible than a fixed pullup/down resistor.

 

Offline bjcuizon

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Re: Components you wish existed.
« Reply #168 on: July 09, 2017, 05:48:53 am »
Just add heatsinks.

Could be, but how about space restraints? ???
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Offline Cerebus

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Re: Components you wish existed.
« Reply #169 on: July 09, 2017, 10:01:17 pm »
- A runtime-reconfigurable CPLD. It starts up with the image last flashed via a dedicated programming connection (say, JTAG) to its internal flash. Groups of pins and cells can be locked into fixed configurations via security bits in the flash. It is through this initial image and a non-programming connection that you reconfigure the remaining cells (say, via SPI). The locking protects the runtime changes from being destructive, such as outputting on a pin that on your board goes to another output. Specification is open enough that you don't need a specialised tool to make these runtime changes.

Something quite close to what you describe could be realised with the 'warmboot' feature of Lattice' iCE40 FPGAs.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline MLXXXp

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Re: Components you wish existed.
« Reply #170 on: July 09, 2017, 10:50:38 pm »
- An adapter that has 2.54mm male header pins on one side (say, 2x5) and individually spring-loaded pins on the other that will make contact with a wide range of PCB hole sizes. The header pins then go to a cable. For testing before soldering real headers on.

- Jumper wire with one end having some kind of connector that lets you make secure, but temporary connections with a plated through-hole of various sizes *vertically* at most points on a PCB.

These ideas are similar to the reusable solderless headers that I wish existed.
https://www.eevblog.com/forum/projects/components-you-wish-existed-88167/msg1206329/?topicseen#msg1206329
 

Offline forrestc

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Re: Components you wish existed.
« Reply #171 on: July 09, 2017, 11:43:35 pm »
I'd like an input protection IC with a circuit like the following:

Back to back depletion-mode mosfets for active current limiting.   Aka the circuit in figure 4.  http://ww1.microchip.com/downloads/en/AppNotes/AN-D66.pdf
and on the 'protected' side:
Transisitor clamps to VCC and GND arranged to burn the excess voltage/current off as heat instead of just shunting the current to the rails.     

All in one package:  In, Out, Vcc, Gnd. 

I can do the above with discretes, but there are numerous reasons why it would be better all in one package.

Bonus for multiple circuits in the same package.

 

Offline GarthyD

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Re: Components you wish existed.
« Reply #172 on: July 10, 2017, 12:00:55 am »
- A runtime-reconfigurable CPLD. It starts up with the image last flashed via a dedicated programming connection (say, JTAG) to its internal flash. Groups of pins and cells can be locked into fixed configurations via security bits in the flash. It is through this initial image and a non-programming connection that you reconfigure the remaining cells (say, via SPI). The locking protects the runtime changes from being destructive, such as outputting on a pin that on your board goes to another output. Specification is open enough that you don't need a specialised tool to make these runtime changes.

Something quite close to what you describe could be realised with the 'warmboot' feature of Lattice' iCE40 FPGAs.

The iCE40 FPGAs are seriously close to ticking all of the boxes here. Thankyou for the excellent suggestion. :) I was wondering if I needed to start wandering into FPGA territory for this sort of functionality.

I was thinking they'd have no leaded variants or would be way too expensive to justify, but I was wrong on both counts: A iCE40HX1K-VQ100 TQFP-100 is about AUD$6.83/USD$5.19 (Mouser). Or AU$8.54 (RS) if I get impatient.

There is an application I'm looking at for the future the could use this and I absolutely will be looking at these when the time comes. For the cost, I might even throw one in my next order just to play with for fun.

In the meantime I've got some interesting reading to do. :)

- An adapter that has 2.54mm male header pins on one side (say, 2x5) and individually spring-loaded pins on the other that will make contact with a wide range of PCB hole sizes. The header pins then go to a cable. For testing before soldering real headers on.

- Jumper wire with one end having some kind of connector that lets you make secure, but temporary connections with a plated through-hole of various sizes *vertically* at most points on a PCB.

These ideas are similar to the reusable solderless headers that I wish existed.
https://www.eevblog.com/forum/projects/components-you-wish-existed-88167/msg1206329/?topicseen#msg1206329


They sound fantastic. I'd love to have had a few of your reusable headers in the prototype board I've just built. Snap in to do testing and measurements, snap out to do some component soldering, and repeat until board is built and the real headers are in.
« Last Edit: July 10, 2017, 01:42:06 am by GarthyD »
 

Offline PointyOintment

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Re: Components you wish existed.
« Reply #173 on: August 04, 2017, 04:46:54 am »
- A conductor/insulator/conductor "sandwich" with a module coming out of the side that you could attach two jumper wires to. To use, you desolder an IC lead from its pad, insert the "sandwich", resolder, and now you can insert something in series between the IC lead and the pad (eg. to measure current). Bonus points if it comes with a tiny DIP switch that you can switch to keep it connected when not in use.
Are there FFCs with double-sided ends? What I mean by that is that the contacts on one side of the end of the FFC go to different traces than the contacts on the other side of the same end. If those exist, you could cut them up and use them for that purpose.

- Fully-assembled boost converter module as a through-hole component with no layout requirements. Five pins: In, out, ground, enable, and a resistor to set voltage.
https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922

- Power-pooling IC that accepts a few power sources and outputs uninterrupted power even as the sources are connected and disconnected. One source assumes a single-cell Li-Po and minimises the voltage drop. The battery source is isolated if the other sources are providing power. An output pin indicates if we are running from battery or not.
Those are called "power multiplexers", I think. Pololu sells one or two on breakout boards.

- Shift register where every two bits controls what is connected to one pin: Either nothing, a weak pullup, or a weak pulldown.
Use a tri-state shift register, and put resistors in series with its outputs?

- A small surface-mount component (0603 or much smaller) that conducts as shipped but you can deliberately break the connection with a small tool, magnifier, and steady hand. Essentially a tiny dip switch with default on.
Solder jumper?

- An adapter that has 2.54mm male header pins on one side (say, 2x5) and individually spring-loaded pins on the other that will make contact with a wide range of PCB hole sizes. The header pins then go to a cable. For testing before soldering real headers on.

- Jumper wire with one end having some kind of connector that lets you make secure, but temporary connections with a plated through-hole of various sizes *vertically* at most points on a PCB.
Tag Connect or Tag-Connect—seems they can't decide if it should be hyphenated or not—is the closest thing I know of to those ideas.
I refuse to use AD's LTspice or any other "free" software whose license agreement prohibits benchmarking it (which implies it's really bad) or publicly disclosing the existence of the agreement. Fortunately, I haven't agreed to that one, and those terms are public already.
 
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Offline GarthyD

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    • Adventures in Electronics
Re: Components you wish existed.
« Reply #174 on: August 04, 2017, 08:31:39 am »
- A conductor/insulator/conductor "sandwich" with a module coming out of the side that you could attach two jumper wires to. To use, you desolder an IC lead from its pad, insert the "sandwich", resolder, and now you can insert something in series between the IC lead and the pad (eg. to measure current). Bonus points if it comes with a tiny DIP switch that you can switch to keep it connected when not in use.
Are there FFCs with double-sided ends? What I mean by that is that the contacts on one side of the end of the FFC go to different traces than the contacts on the other side of the same end. If those exist, you could cut them up and use them for that purpose.

That's a really interesting idea. I've done little with the connectors on flat cables so I wouldn't be sure where to start, but perhaps such a connector exists that would somehow allow it to be attached in that way.

- Fully-assembled boost converter module as a through-hole component with no layout requirements. Five pins: In, out, ground, enable, and a resistor to set voltage.
https://www.digikey.com/products/en/power-supplies-board-mount/dc-dc-converters/922

I had a lot of trouble finding one that definitely converted voltage upward and thought you might have been mistaken. However, after some digging I was able to find some that definitely did. Some more digging in the higher price ranges yielded packages with both through-hole and surface mount (with leads). I didn't find one with every characteristic, but I found a few that were awfully close. I blame the search tools, the suggestion was great. :)

A search for "step-up" and "boost" in a few stores that do breakout boards yielded some results that ticks all the boxes apart from being a fully-assembled module (although the last point could be argued).

- Power-pooling IC that accepts a few power sources and outputs uninterrupted power even as the sources are connected and disconnected. One source assumes a single-cell Li-Po and minimises the voltage drop. The battery source is isolated if the other sources are providing power. An output pin indicates if we are running from battery or not.
Those are called "power multiplexers", I think. Pololu sells one or two on breakout boards.

And so they are! That's the problem I run into a lot. I can describe the type of thing I want but it's hard to find it without knowing what it is actually called. Thanks for pointing me in the right direction.

- Shift register where every two bits controls what is connected to one pin: Either nothing, a weak pullup, or a weak pulldown.
Use a tri-state shift register, and put resistors in series with its outputs?

Heck, that's seriously close. I didn't know there were tri-state shift registers. :O Now, an all that is left is an all-in-one package with the resistors included.

- A small surface-mount component (0603 or much smaller) that conducts as shipped but you can deliberately break the connection with a small tool, magnifier, and steady hand. Essentially a tiny dip switch with default on.
Solder jumper?

Do you mean solder over a point, and desolder to break? I was thinking more along the lines of something that someone without an iron could safely break if they wanted to. Perhaps like a surface mount resistor but with a conductive middle segment sitting on a nonconductive base that you can push out of the component. Or something with a tiny, tiny switch that you can flick maybe a dozen times before it breaks. Or something that comes with a small wire in it that you can slice with a small blade.

- An adapter that has 2.54mm male header pins on one side (say, 2x5) and individually spring-loaded pins on the other that will make contact with a wide range of PCB hole sizes. The header pins then go to a cable. For testing before soldering real headers on.

- Jumper wire with one end having some kind of connector that lets you make secure, but temporary connections with a plated through-hole of various sizes *vertically* at most points on a PCB.
Tag Connect or Tag-Connect—seems they can't decide if it should be hyphenated or not—is the closest thing I know of to those ideas.

Kind of, but without the requirement of putting in extra holes to match the connector. The sort of thing which you could build yourself by attaching ribbon wires to a set of pogo pins offset by 2.54mm with pointy or mildly-rounded ends (matching any hole size) and attach the other end to an IDC cable. Except without the building it yourself part, just jump straight to the part where I buy the already-assembled cable. :)

...

Thankyou, wish-granting electronics genie. :)

Seriously: Thankyou for the excellent suggestions and starting points. :)
 


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