4 ms·

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

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 ?

kube-system 5y ago
I believe the old Dell chargers simply have a data pin, which I presume would carry the data generated by this project
- tgflynn 5y ago
  I guess it would also be helpful to know what range of laptops this is for. I was assuming it was for relatively recent models. I have an Inspiron that's about 5 years old and it has a barrel connector for power. It's not obvious that it contains a third pin. I have at times had problems with the laptop refusing to recognize various power adapters though.
dec0dedab0de 5y ago
It's a bit over my head, but the schematic in the readme seems to have a shared ground, with one pin going to the attiny microcontroller, and the other going to a generic power source. With a big warning that your power source needs to be up to spec.
- tgflynn 5y ago
  If the connector on the left represents the output of a generic power supply then I still don't see how you would connect this on the laptop side. EDIT: On further thought I think that connector must be intended to represent the laptop input and Vcc is the output of a generic power supply (with sufficient voltage and current capacity). It was not clear to me because my Dell laptop doesn't appear to have a 3-pin power connector so maybe this only applies to certain models.
zelon88 5y ago
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.
- tgflynn 5y ago
  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.
  - camtarn 5y ago
    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.
    - tgflynn 5y ago
      Thanks, that's useful information that I haven't seen anywhere else.
stavros 5y ago
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.

kube-system 5y ago

I believe the old Dell chargers simply have a data pin, which I presume would carry the data generated by this project

tgflynn 5y ago
I guess it would also be helpful to know what range of laptops this is for. I was assuming it was for relatively recent models. I have an Inspiron that's about 5 years old and it has a barrel connector for power. It's not obvious that it contains a third pin. I have at times had problems with the laptop refusing to recognize various power adapters though.

dec0dedab0de 5y ago

It's a bit over my head, but the schematic in the readme seems to have a shared ground, with one pin going to the attiny microcontroller, and the other going to a generic power source. With a big warning that your power source needs to be up to spec.

tgflynn 5y ago
If the connector on the left represents the output of a generic power supply then I still don't see how you would connect this on the laptop side. EDIT: On further thought I think that connector must be intended to represent the laptop input and Vcc is the output of a generic power supply (with sufficient voltage and current capacity). It was not clear to me because my Dell laptop doesn't appear to have a 3-pin power connector so maybe this only applies to certain models.

zelon88 5y ago

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.

tgflynn 5y ago
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.
- camtarn 5y ago
  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.
  - tgflynn 5y ago
    Thanks, that's useful information that I haven't seen anywhere else.

stavros 5y ago

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.