I see several choices for the switches: - Analog resistor ladder (probably 6-bit at most, so 4 ADC inputs) - Individual-scan (which can only scan one switch per display refresh) - Dedicated shift registers (most expensive, but neatest in software) - A compromise with one shift register, using spare outputs to decode rows of a 3x8 matrix. - A compromise with two shift registers, using a resistor ladder, or even dedicated GPIOs for the remaining 6 switches. Looking forward to the result in any case!
You could read all the switches by connecting them to the LEDs, selectively turning the LEDs on, and reading a single common sense line. That is - if you don't want to put another set of shift registers for the switches
Maybe you should collaborate with the folks at Hackerboxes? Seems like you come up with a lot of unique educational gadgets that might work for one or more of their monthly project boxes.
I don't want to sound negative, but the amount of IO you have here, as well as all those shift registers and the tiny makes me disappointed it's not a little more to it. Now if you used the 595s to make a Linear Feedback Shift Register using the switches as the inputs that would be cool, or as other have suggested implementing some kind of limited 8080 style computer or trainer board it would be a really cool project. It's so close to a *really* cool project.
The switches are junk and don’t have the correct function. Some need to be momentary up down. If someone can find me good switches I’ll consider a more functional one. In the meantime buy a clone from the high nibble.
Like me, my IMSAI 8080 must be getting really old. I'm thinking of pulling it out of storage and testing it. If it still runs, I might have to decide what to do with it.
Hi, I am the CEO of the National IMSAI and ALTAIR Disposal Group, NIADG for short. Please package your IMSAI unit and all accessories with documentation and ship it to me for proper disposal. No fees are charged ! LOL !! Kidding aside, I restore these old systems as a hobby/ side business. If you are interested in selling your IMSAI stuff, keep me in mind, Thanks Glenn
Nice pcb I alway double via on pcb... I use donut of 20mil and hole of 13mil, via cost nothing, double vias make sure you are never trouble contact between top and bottom. 7mil on data trace, 15mil on VCC chip trace for low power. 1206 smt for easy assembly, 0805 for more dense but easy (i use this size 90% of time), 0603 part for very high density on manuel assembly, under 0603 is this hard to do in manuel for project, is ok for repaire.
You've been honing your pcb design skills. How about designing pcb project for modern interpretation of the Tek curve tracers? Low power testers like dcapro can't test like the 577. The old tracers don't have data export and are huge. I realize there are simple curve tracer examples already out there.
that's a project I keep thinking about. I did this one: ua-cam.com/video/oFHTOQTIi30/v-deo.html and thought of making a PCB for that old design (pretty it up). getting all the functionality of the TEK would be a lot of engineering
@IMSAIGuy I just rewatched that series. Your version would have higher power ability than the dcapro, which I see as dcapro's main shortcoming. Creating user interface to automate the fiddling for doing diodes, npn and pnp would be a sizeable programming job. Relay controls, safety features, and error handling make that more than a hobbiest project.
The tektronix 571 is a 1990's version of curve tracer and works 20lb. Perhaps it's functionality would be a better model for new interpretation. I'll look for the schematics.
*Building a Fun Gadget: An MSI 8080 Microcomputer Replica* * *0:00:11** Project Overview:* The project involves creating a replica of an MSI 8080 microcomputer, designed primarily for aesthetic appeal rather than full functionality. * *0:00:30** Limited Functionality:* The replica will feature flashing LEDs and respond to select switch inputs, but it won't be a fully operational computer. * *0:00:37** LED Control:* An ATtiny 814 microcontroller will manage all the LEDs, allowing individual control over each one. * *0:00:41** Switch Input:* The replica will incorporate functional power and run switches, along with three address line switches for selecting different operational modes. * *0:02:07** Power and Components:* Power will be supplied externally, and the back of the device will house the microcontroller, resistors for the LEDs, and shift registers for controlling the LEDs. * *0:02:28** Schematic Details:* The schematic reveals the use of an ATtiny 814 microcontroller, 595 shift registers for LED control, and connections for select switches. * *0:03:16** Programming Access:* A dedicated pin will be included for programming the microcontroller. * *0:03:24** Power Switch Functionality:* The power switch on the replica will function as a true power switch, controlling the flow of VCC (power supply voltage). * *0:03:31** Project Goal:* The main objective is to create an enjoyable, visually appealing toy that resembles the MSI 8080 microcomputer. I used gemini-1.5-pro-exp-0827 on rocketrecap dot com to summarize the transcript. Cost (if I didn't use the free tier): $0.0188 Input tokens: 13574 Output tokens: 364
Cool, but after this much effort and adding functional bits, I'd be tempted to go the extra step and make it a functioning emulator.
ua-cam.com/video/VBEgPC2zSLc/v-deo.htmlsi=lOUGRcdUSKHyT1vM
I see several choices for the switches:
- Analog resistor ladder (probably 6-bit at most, so 4 ADC inputs)
- Individual-scan (which can only scan one switch per display refresh)
- Dedicated shift registers (most expensive, but neatest in software)
- A compromise with one shift register, using spare outputs to decode rows of a 3x8 matrix.
- A compromise with two shift registers, using a resistor ladder, or even dedicated GPIOs for the remaining 6 switches.
Looking forward to the result in any case!
ua-cam.com/video/VBEgPC2zSLc/v-deo.htmlsi=lOUGRcdUSKHyT1vM
You could read all the switches by connecting them to the LEDs, selectively turning the LEDs on, and reading a single common sense line. That is - if you don't want to put another set of shift registers for the switches
that's a clever idea
IMSAI Guy making an IMSAI.... awesome!
Maybe you should collaborate with the folks at Hackerboxes? Seems like you come up with a lot of unique educational gadgets that might work for one or more of their monthly project boxes.
I don't want to sound negative, but the amount of IO you have here, as well as all those shift registers and the tiny makes me disappointed it's not a little more to it.
Now if you used the 595s to make a Linear Feedback Shift Register using the switches as the inputs that would be cool, or as other have suggested implementing some kind of limited 8080 style computer or trainer board it would be a really cool project.
It's so close to a *really* cool project.
The switches are junk and don’t have the correct function. Some need to be momentary up down. If someone can find me good switches I’ll consider a more functional one. In the meantime buy a clone from the high nibble.
@IMSAIGuy entirely fair. Love the channel and chip of the day!
Looks more like a Gonculator rather than a Gadget ;)
It possible to use ESP32 instead of AtTiny, and run 8080 software emulation...
build one: ua-cam.com/video/_YcnYG_SSnE/v-deo.htmlsi=xIYtZZKtyQlvz_uq
It runs DOOM, right?
No, just “Hello world.”
I saw 8080, and thought, oh, an old Intel Microprocessor, so of course DOOM!!
Real men build 8008 systems. 🙂
Like me, my IMSAI 8080 must be getting really old. I'm thinking of pulling it out of storage and testing it. If it still runs, I might have to decide what to do with it.
Hi, I am the CEO of the National IMSAI and ALTAIR Disposal Group, NIADG for short. Please package your IMSAI unit and all accessories with documentation and ship it to me for proper disposal. No fees are charged ! LOL !!
Kidding aside, I restore these old systems as a hobby/ side business. If you are interested in selling your IMSAI stuff, keep me in mind, Thanks Glenn
Right. If you have an original IKB-1 I've got a couple K USD. Care to swap?
Nice pcb
I alway double via on pcb...
I use donut of 20mil and hole of 13mil, via cost nothing, double vias make sure you are never trouble contact between top and bottom.
7mil on data trace, 15mil on VCC chip trace for low power.
1206 smt for easy assembly, 0805 for more dense but easy (i use this size 90% of time), 0603 part for very high density on manuel assembly, under 0603 is this hard to do in manuel for project, is ok for repaire.
can it make julienne fries?
Why not make it fully functional? With modern technology that should be possible.
ua-cam.com/video/VBEgPC2zSLc/v-deo.htmlsi=lOUGRcdUSKHyT1vM
You've been honing your pcb design skills. How about designing pcb project for modern interpretation of the Tek curve tracers? Low power testers like dcapro can't test like the 577. The old tracers don't have data export and are huge.
I realize there are simple curve tracer examples already out there.
that's a project I keep thinking about. I did this one: ua-cam.com/video/oFHTOQTIi30/v-deo.html and thought of making a PCB for that old design (pretty it up). getting all the functionality of the TEK would be a lot of engineering
@IMSAIGuy I just rewatched that series. Your version would have higher power ability than the dcapro, which I see as dcapro's main shortcoming. Creating user interface to automate the fiddling for doing diodes, npn and pnp would be a sizeable programming job. Relay controls, safety features, and error handling make that more than a hobbiest project.
The tektronix 571 is a 1990's version of curve tracer and works 20lb. Perhaps it's functionality would be a better model for new interpretation. I'll look for the schematics.
*Building a Fun Gadget: An MSI 8080 Microcomputer Replica*
* *0:00:11** Project Overview:* The project involves creating a replica of an MSI 8080 microcomputer, designed primarily for aesthetic appeal rather than full functionality.
* *0:00:30** Limited Functionality:* The replica will feature flashing LEDs and respond to select switch inputs, but it won't be a fully operational computer.
* *0:00:37** LED Control:* An ATtiny 814 microcontroller will manage all the LEDs, allowing individual control over each one.
* *0:00:41** Switch Input:* The replica will incorporate functional power and run switches, along with three address line switches for selecting different operational modes.
* *0:02:07** Power and Components:* Power will be supplied externally, and the back of the device will house the microcontroller, resistors for the LEDs, and shift registers for controlling the LEDs.
* *0:02:28** Schematic Details:* The schematic reveals the use of an ATtiny 814 microcontroller, 595 shift registers for LED control, and connections for select switches.
* *0:03:16** Programming Access:* A dedicated pin will be included for programming the microcontroller.
* *0:03:24** Power Switch Functionality:* The power switch on the replica will function as a true power switch, controlling the flow of VCC (power supply voltage).
* *0:03:31** Project Goal:* The main objective is to create an enjoyable, visually appealing toy that resembles the MSI 8080 microcomputer.
I used gemini-1.5-pro-exp-0827 on rocketrecap dot com to summarize the transcript.
Cost (if I didn't use the free tier): $0.0188
Input tokens: 13574
Output tokens: 364
nice
it had a hard time with IMSAI got MSI
Fake switches? Lazy and lame. You have a micro! Make it work.
ua-cam.com/video/VBEgPC2zSLc/v-deo.htmlsi=lOUGRcdUSKHyT1vM