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Emulator of Original Dell Charger Using ATTINY85

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Re: Emulator of Original Dell Charger Using ATTINY85

#21

Post by stavros »

tgflynn wrote: post #4

I assume the purpose of this would be to build a Dell compatible charger but this repo doesn't appear to provide much information on how to actually do that. I get that the microcontroller provides the signalling the laptop needs to identify the charger, but assuming you built this circuit, how would you actually use it to charge a laptop ?

Looks like you connect the data pin of the ATTiny to the data pin of the charger jack. The schematic only has two components, the ATTiny and a power regulator for it, then the input is charger power and the output is charger power + data.

Re: Emulator of Original Dell Charger Using ATTINY85

#22

Post by tgflynn »

zelon88 wrote: post #18
tgflynn wrote: post #4

I assume the purpose of this would be to build a Dell compatible charger but this repo doesn't appear to provide much information on how to actually do that. I get that the microcontroller provides the signalling the laptop needs to identify the charger, but assuming you built this circuit, how would you actually use it to charge a laptop ?

In schematic.png you can see on the left there are 3 pins and the right there are 2 pins. The 3 pins on the left represent the laptop and the two pins on the right represent the power supply. The chip in the middle attaches to the ID pin on the laptop and reports the charger to the laptop.

Yes, I was confused because my Dell laptop power input doesn't have 3 wires (unless there's somehow a third wire buried in the barrel connector), so I was assuming that the ID signal is somehow just combined with the actual input voltage.

Re: Emulator of Original Dell Charger Using ATTINY85

#23

Post by londons_explore »

tpmoney wrote: post #15
londons_explore wrote: post #12

I don't understand why people use the attiny85... The Atmega328 based boards have far wider software support in the arduino ecosystem, so you will typically be able to prototype a project in minutes instead of hours, and the dev boards cost the same, but the 328 ones have more of pretty much everything. The only benefit of the attiny seems to be that you can save a few millimeters of board space, but if that's your c…

The obvious answer would probably be the size and the dip formfactor. Sure you can get more capable BGA packaged chips, but how many hobbyists have the ability to properly solder in a BGA?

The 328 is also available in dip...

Re: Emulator of Original Dell Charger Using ATTINY85

#24

Post by tpmoney »

londons_explore wrote: post #23
tpmoney wrote: post #15

Earlier quoted context omitted.

The obvious answer would probably be the size and the dip formfactor. Sure you can get more capable BGA packaged chips, but how many hobbyists have the ability to properly solder in a BGA?

The 328 is also available in dip...

It’s also 10 pins longer, so as you point out saving space may be a requirement

Re: Emulator of Original Dell Charger Using ATTINY85

#25

Post by rektide »

I just learned this week that my old Dell Venue 11 Pro's will happily accept 19/20V if given, without any sideband communication. The laptop has a custom Dell charger, and usb-micro input, which could negotiate via a custom protocol to a higher power level.

But folks are reporting that if you make a 20V USB-micro, they'll charge. Sweet. Riskier than this links careful negotiation over 1-wire, but so convenient. I'll probably rip apart one of my usb-c to 20v barrel jacks & make a cable, in case I want to go back to these units. The need for a custom charger has been a huge barrier to ever wanting to use them again, very nice that these old systems will just work, when given power.

Re: Emulator of Original Dell Charger Using ATTINY85

#26

Post by jononor »

auxym wrote: post #11
bxparks wrote: post #7

The ATtiny85 is nice, with 8kB flash, 512 bytes RAM & EEPROM, 5-6 GPIO pins, they are just enough to do something interesting. But I don't use the ATtiny85 as much as I want to, because flashing requires a separate programmer hardware. It's enough friction to get in the way of rapid software iteration. I once made the mistake of inserting the ATtiny85 upside down into the programmer, and it promptly cooked it dead. L…

All micros require separate hardware to flash it, no? Some is cheap (stlink), some are a few hundred dollars, but still. Unless you have a USB bootloader programmed on the chip, but you still need the adapter to flash the bootloader in the first place.

Not at all! Many devices can be flashed over USB, for example. Many STM32 devices come with a bootloader factory programmed in a read only area that implement USB DFU. Many user-provided software bootloaders can do the same on many other devices. Including the attiny85 using bit banging!

And of course with wireless enabled microcontrollers one can update over the air. Nordic NRF5x over Bluetooth for example, or ESP32 over WiFi.

Re: Emulator of Original Dell Charger Using ATTINY85

#27

Post by danhor »

auxym wrote: post #11
bxparks wrote: post #7

The ATtiny85 is nice, with 8kB flash, 512 bytes RAM & EEPROM, 5-6 GPIO pins, they are just enough to do something interesting. But I don't use the ATtiny85 as much as I want to, because flashing requires a separate programmer hardware. It's enough friction to get in the way of rapid software iteration. I once made the mistake of inserting the ATtiny85 upside down into the programmer, and it promptly cooked it dead. L…

All micros require separate hardware to flash it, no? Some is cheap (stlink), some are a few hundred dollars, but still. Unless you have a USB bootloader programmed on the chip, but you still need the adapter to flash the bootloader in the first place.

Another exception is the esp32-c3, which includes a jtag debugger inside the chip (not on board, inside the same die)

Re: Emulator of Original Dell Charger Using ATTINY85

#28

Post by camtarn »

tgflynn wrote: post #22
zelon88 wrote: post #18

Earlier quoted context omitted.

In schematic.png you can see on the left there are 3 pins and the right there are 2 pins. The 3 pins on the left represent the laptop and the two pins on the right represent the power supply. The chip in the middle attaches to the ID pin on the laptop and reports the charger to the laptop.

Yes, I was confused because my Dell laptop power input doesn't have 3 wires (unless there's somehow a third wire buried in the barrel connector), so I was assuming that the ID signal is somehow just combined with the actual input voltage.

Yes, the barrel connector actually has three contacts. The inner and outer part of the metal barrel are insulated from each other - the outer is ground and the inner is +V. The pin in the middle only carries data.

Re: Emulator of Original Dell Charger Using ATTINY85

#29

Post by MarioMan »

bxparks wrote: post #7

The ATtiny85 is nice, with 8kB flash, 512 bytes RAM & EEPROM, 5-6 GPIO pins, they are just enough to do something interesting. But I don't use the ATtiny85 as much as I want to, because flashing requires a separate programmer hardware. It's enough friction to get in the way of rapid software iteration. I once made the mistake of inserting the ATtiny85 upside down into the programmer, and it promptly cooked it dead. L…

The Digispark[1] and its clones use the ATTINY85 and offer flashing over USB via the Micronucleus bootloader[2] using V-USB[3]. It comes at the cost of a significant chunk of flash storage, but the convenience is excellent. Plus, V-USB support means you can emulate all sorts of USB devices. I've used it to build a DIY NES controller adapter, but it's commonly used as a cheap Rubber Ducky[4]. For projects where USB interfacing makes sense, it can be a good fit.

1: http://digistump.com/products/1

2: https://github.com/micronucleus/micronucleus

3: https://www.obdev.at/products/vusb/index.html

4: https://shop.hak5.org/products/usb-rubber-ducky-deluxe

Re: Emulator of Original Dell Charger Using ATTINY85

#30

Post by tgflynn »

camtarn wrote: post #28
tgflynn wrote: post #22

Earlier quoted context omitted.

Yes, I was confused because my Dell laptop power input doesn't have 3 wires (unless there's somehow a third wire buried in the barrel connector), so I was assuming that the ID signal is somehow just combined with the actual input voltage.

Yes, the barrel connector actually has three contacts. The inner and outer part of the metal barrel are insulated from each other - the outer is ground and the inner is +V. The pin in the middle only carries data.

Thanks, that's useful information that I haven't seen anywhere else.
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