How I got sponsored - Page 1
Forum section: electronics / projects

author: IceEstonia
author_rank: Newbie
timestamp: February 26, 2025, 12:17:09 pm
content: Hi,couple of years back my little brother asked me about logic gates, what are they. Of course you could give the obv answer that for example AND gate it when you have the both inputs high and then the output is high but you could see from he´s face.... what are input/output, whats the AND gate etc. The idea behind it is quite simple but explaining that to someone who has any idea about it turned out to be quite difficult.Rather than develop my explanation skills I took the engineer route and made a board to help him out. A product was born:And of course the only feedback I got from him was : "That’s cool, I guess".But at least I had fun desigin it, and I have never worked upon something where a lot of effort is put into the appearance of the PCB.Then one day I noticed that PCBWay have their yearly design contest, and I put it up there. All of a sudden, an email for their sponsorship came. I was ofcourse quite delighter that this kind of project could even achive something like that. So I guess educational stuff gets sponored qutie easily (n=1).I have made the project open soruce, find all of the files/guides etc fromwww.logicgat.es.

author: passedpawn
author_rank: Contributor
timestamp: February 27, 2025, 02:02:32 am
content: Nifty. So, being old, I don't need such a learning tool. I'd still like one. Can I buy it on pcbway with my zillion "beans" that I've never used?

author: IceEstonia
author_rank: Newbie
timestamp: February 27, 2025, 10:04:22 am
content: Most defenetly you can buy one with your zillion beans from PCBWay. I have it up, athttps://www.pcbway.com/project/shareproject/Logic_Gates_f5d0cca7.htmljust couple of clicks and you have one made for yourself. But bare in mind that, if you order from pcbway, you have to program the board aswell. The codes an everything are up on my gitlab, but you still need to have the neccecery tools to program the STM32 board.Also you can buy one from me aswellhttps://www.ebay.com/itm/197035330860

author: kripton2035
author_rank: Super Contributor
timestamp: February 27, 2025, 11:20:57 am
content: cool design !may be you could add in the github a pdf of the schematic and the gerber of the pcb for people who do not want (or can't) install altium ?

author: squadchannel
author_rank: Frequent Contributor
timestamp: February 27, 2025, 11:37:42 am
content: Nice project.But why did you use STM32? I would like to know why you did not use single channel logic gates.

author: langwadt
author_rank: Super Contributor
timestamp: February 27, 2025, 12:30:17 pm
content: Quote from: squadchannel on February 27, 2025, 11:37:42 amor if you want a short simple BOM some quad NAND

author: IceEstonia
author_rank: Newbie
timestamp: February 27, 2025, 01:00:33 pm
content: I will add the schematic as a PDF as soon as possible.For this project, I initially used NAND gates, thinking they would be a cost-effective way to implement logic gates. However, contrary to my initial belief, the manufacturing cost ended up being just as high as using an STM32, without offering the flexibility of an MCU.Another issue with NAND gates was the routing. While it was possible to route the board, the result was visually unappealing. Given that aesthetics were a key focus in this project, I decided to abandon the NAND gate approach.Using separate logic gates would have further increased the component count in my BOM, leading to higher manufacturing costs. I aimed to keep the BOM as minimal as possible.

author: Nominal Animal
author_rank: Super Contributor
timestamp: February 27, 2025, 01:08:35 pm
content: Nice!While I'm more of a software person and just a hobbyist in electronics, I would've used 74LVC1G57W6-7 or SN74LVC1G57DBVR, and SN74LVC1G58DBVR instead. These are multifunction single logic gates with three inputs and one output, in SOT23-6; hand-solderable and cheap, and can handle the 1mA .. 10mA of current you might want to light the LED with. For higher current, I'd use NX138AK or BSS138 N-channel MOSFETs as a low-side switch.By picking which input to use, and tying the two others to GND/VCC, they can implement most of the different logic gate types. The two have different truth tables, so that among the two types, you get all different logic gates.And I'd use tactile buttons instead of slide switches –– the 12mm × 12mm kind, not the 6mm × 6mm dinky kind. Just because how they feel when pushing with a finger.But most importantly: it never even crossedmymind to do something like this. For OP, it did!Now, I think that after verifying one it, I'd havethe askersolder their own, providing just the boards, components, and a CR2032 battery. LEDs and buttons on the nice side, logic, current-limiting resistors and CR2032 holder on the other side with rubber feet.In any case, brilliant idea. I like it.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 27, 2025, 01:22:28 pm
content: Using a small MCU certainly lowers costs here to an insignificant amount compared to using single-gate ICs. The OP mentioned STM32, I don't know which one, but going for a CH32V003 would get it to an even lower price point.From an educational standpoint, it may make more sense to use discrete logic. But from a cost standpoint, the MCU wins.

author: langwadt
author_rank: Super Contributor
timestamp: February 27, 2025, 03:35:24 pm
content: Quote from: SiliconWizard on February 27, 2025, 01:22:28 pmwith a cheat a few 3 cent logic gates will do

author: Nominal Animal
author_rank: Super Contributor
timestamp: February 27, 2025, 05:08:51 pm
content: Quote from: SiliconWizard on February 27, 2025, 01:22:28 pmYep, definitely. And if you don't make them (at least some of them) solder one themselves, the implementation does not matter.Except for the buttons. My fingers don't like slide switches. They like the larger 12mm tactiles buttons.

author: Zero999
author_rank: Super Contributor
timestamp: February 28, 2025, 11:01:23 am
content: I'm a bit perplexed as to why you need an MCU or even logic gates. The only semiconductors you need are the LEDs.Put the switches in series or parallel for AND and OR. If it's inverting, just flip the switch over.For XOR, use SPDT switches, which going by the photographs, those PCB mount toggle switches usually are.

author: langwadt
author_rank: Super Contributor
timestamp: February 28, 2025, 11:45:59 am
content: Quote from: Zero999 on February 28, 2025, 11:01:23 ammissing LEDs on the inputs, easily done with DPDT~$0.05,https://jlcpcb.com/partdetail/Hanxia-HXMSS22D18G2/C5149820

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 28, 2025, 02:02:26 pm
content: Quote from: Nominal Animal on February 27, 2025, 05:08:51 pmThat's a good idea. Pushbuttons would be nicer than slide switches here, and since there are LEDs to show the state of the inputs, that would be fine.Would be every bit as easy to implement in firmware too and a benefit for having a MCU (doing this with discrete logic would require more gates for implementing SR latches).

author: Faranight
author_rank: Unknown
timestamp: February 28, 2025, 04:00:41 pm
content: Very nice and educational project. Do you think you could also make a version with latch circuits like SR latch, D-latch, JK flip-flop, T flip-flop and similar?

author: Zero999
author_rank: Super Contributor
timestamp: February 28, 2025, 06:39:43 pm
content: Quote from: langwadt on February 28, 2025, 11:45:59 amOh, I forgot about the LEDs on the input. Yes, DPDT switches are the answer for indicating the input status.Quote from: Faranight on February 28, 2025, 04:00:41 pmIf you go for a flip-flops, please use relays. It makes it easier to understand. Here's a T flio-flop which only uses relays.

author: Nominal Animal
author_rank: Super Contributor
timestamp: March 01, 2025, 10:22:45 am
content: Just to reiterate and make it absolutely clear to OP we're supportive, not not being negative here: this is how engineers and scientists show support, by discussing alternatives and further development. If we didn't care, we wouldn't respond at all. Just so you know, being a new member an all, okay?