General > General Technical Chat
are drawing normal schematics a dying art?
Zero999:
--- Quote from: Berni on November 29, 2021, 06:50:26 am ---So as long as you need anything more than just a constant frequency blink it will actually be cheaper to use a tiny 6 pin MCU, also its more compact. I went down the path of designing an analog circuit for a easy task, only to get half way there, realize this takes a lot of components to do properly, then throw it away and replace it with a MCU.
--- End quote ---
You can't get much cheaper than a Schmitt trigger IC, such as the 74HC1G14 + RC circuit and costs less than the cheapest MCU, in small quantities.
If all I wanted was a flashing LED, just use a self-flashing LED: no discrete components, or coding required!
eti:
--- Quote from: Zero999 on November 29, 2021, 09:50:45 am ---
--- Quote from: Berni on November 29, 2021, 06:50:26 am ---So as long as you need anything more than just a constant frequency blink it will actually be cheaper to use a tiny 6 pin MCU, also its more compact. I went down the path of designing an analog circuit for a easy task, only to get half way there, realize this takes a lot of components to do properly, then throw it away and replace it with a MCU.
--- End quote ---
You can't get much cheaper than a Schmitt trigger IC, such as the 74HC1G14 + RC circuit and costs less than the cheapest MCU, in small quantities.
If all I wanted was a flashing LED, just use a self-flashing LED: no discrete components, or coding required!
--- End quote ---
I remember seeing flashing red LEDs in “Tandy” in the UK, back in the 90s, for about £4, and I recall thinking what a ripoff it was 😁
It was, but they’re great.
Berni:
--- Quote from: Zero999 on November 29, 2021, 09:50:45 am ---
--- Quote from: Berni on November 29, 2021, 06:50:26 am ---So as long as you need anything more than just a constant frequency blink it will actually be cheaper to use a tiny 6 pin MCU, also its more compact. I went down the path of designing an analog circuit for a easy task, only to get half way there, realize this takes a lot of components to do properly, then throw it away and replace it with a MCU.
--- End quote ---
You can't get much cheaper than a Schmitt trigger IC, such as the 74HC1G14 + RC circuit and costs less than the cheapest MCU, in small quantities.
If all I wanted was a flashing LED, just use a self-flashing LED: no discrete components, or coding required!
--- End quote ---
Yes this is why i brought up flashing with something more than just a fixed frequency. Like you want it to flash 3 times upon seeing a rising edge on a input, or you want it to flash in a pattern of 2 flashes every x seconds. Or perhaps you also want a certain beep to accompany it. There are lots of these simple tasks that sound like a pretty dumb task for a MCU, yet still require a fair number of components to put together. The use of a MCU also provides easy communicability as sometimes when you first put together the prototype you find it doesn't work that well and needs to work slightly differently, no need to bodge circuitry onto it, just change a few lines of code.
It is indeed much less satisfying of a solution, but it gets the job done.
For example the task of turning on the lights when it gets dark is easy to do in analog, its one of the most basic projects. But i wanted this thing to be fairly robust, so i used a IR sensor that can't see light from the CFL bulbs (White LEDs ware not quite there yet back then), but it can see halogen car headlights, yet i don't want to unnecessarily cycle the CFL bulbs. So i needed a really slow low pass filter, it turned out to be annoying to make without huge capacitors or high impedance nodes (this is outside so i don't want high impedance) then i also need a schmitt tiger, then i also wanted to lock out changing state for 15 minute after a turn on, again requiring a slow timer. In the end a MCU with a A4 paper worth of code was the solution and its still running today. The 'cost saving' was made even more significant since it was a one off done on perfboard, so extra components mean more work to wire it all up.
Zero999:
--- Quote from: eti on November 29, 2021, 10:02:26 am ---
--- Quote from: Zero999 on November 29, 2021, 09:50:45 am ---
--- Quote from: Berni on November 29, 2021, 06:50:26 am ---So as long as you need anything more than just a constant frequency blink it will actually be cheaper to use a tiny 6 pin MCU, also its more compact. I went down the path of designing an analog circuit for a easy task, only to get half way there, realize this takes a lot of components to do properly, then throw it away and replace it with a MCU.
--- End quote ---
You can't get much cheaper than a Schmitt trigger IC, such as the 74HC1G14 + RC circuit and costs less than the cheapest MCU, in small quantities.
If all I wanted was a flashing LED, just use a self-flashing LED: no discrete components, or coding required!
--- End quote ---
I remember seeing flashing red LEDs in “Tandy” in the UK, back in the 90s, for about £4, and I recall thinking what a ripoff it was 😁
It was, but they’re great.
--- End quote ---
Everything was expensive in Tandy. Basic components, such as a plain old TO-92 BJT, 741, 555 timer etc. cost around £1 each. They used to be sold in blister packs with the component sealed inside a vacuum formed bubble, stuck to a piece of cardboard, with a basic datasheet printed on the back. Worse still, the packaging wasn't even ESD proof. I'm pretty sure I had bought faulty components from Tandy, but as I was only 12 at the time and a complete beginner, I didn't have the confidence to complain, as I thought it might've been my fault.
I remember seeing a few empty packets in the store. Either someone had stolen the components, or the glue had started to fail, allowing them to fall on the floor and presumably vacuumed up. They probably lost as many parts, as they sold.
I remember discovering Maplin, which was much cheaper and sold a greater range of components, but there wasn't one in my town, so my dad occasionally drove me 10 miles to go there. Eventually a Maplin did open near me, but by then Tandy had gone and it had deteriorated to the point of being useless, for most things.
eti:
--- Quote from: Zero999 on November 29, 2021, 11:56:17 am ---
--- Quote from: eti on November 29, 2021, 10:02:26 am ---
--- Quote from: Zero999 on November 29, 2021, 09:50:45 am ---
--- Quote from: Berni on November 29, 2021, 06:50:26 am ---So as long as you need anything more than just a constant frequency blink it will actually be cheaper to use a tiny 6 pin MCU, also its more compact. I went down the path of designing an analog circuit for a easy task, only to get half way there, realize this takes a lot of components to do properly, then throw it away and replace it with a MCU.
--- End quote ---
You can't get much cheaper than a Schmitt trigger IC, such as the 74HC1G14 + RC circuit and costs less than the cheapest MCU, in small quantities.
If all I wanted was a flashing LED, just use a self-flashing LED: no discrete components, or coding required!
--- End quote ---
I remember seeing flashing red LEDs in “Tandy” in the UK, back in the 90s, for about £4, and I recall thinking what a ripoff it was 😁
It was, but they’re great.
--- End quote ---
Everything was expensive in Tandy. Basic components, such as a plain old TO-92 BJT, 741, 555 timer etc. cost around £1 each. They used to be sold in blister packs with the component sealed inside a vacuum formed bubble, stuck to a piece of cardboard, with a basic datasheet printed on the back. Worse still, the packaging wasn't even ESD proof. I'm pretty sure I had bought faulty components from Tandy, but as I was only 12 at the time and a complete beginner, I didn't have the confidence to complain, as I thought it might've been my fault.
I remember seeing a few empty packets in the store. Either someone had stolen the components, or the glue had started to fail, allowing them to fall on the floor and presumably vacuumed up. They probably lost as many parts, as they sold.
I remember discovering Maplin, which was much cheaper and sold a greater range of components, but there wasn't one in my town, so my dad occasionally drove me 10 miles to go there. Eventually a Maplin did open near me, but by then Tandy had gone and it had deteriorated to the point of being useless, for most things.
--- End quote ---
Yeah I remember seeing the same poor old CPU sitting on their shelves for many years, cardboard fading. I can’t imagine anyone needing such a niche product or knowing what it was, in our rather basic, backwater town. 😂
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