On Thu, 02 Jan 2020 17:39:41 +0000, The Natural Philosopher wrote:

> On 02/01/2020 16:57, Toby Newman wrote:
>> On 2019-12-20, nev young  wrote:
>>> On 19/12/2019 13:02, Toby Newman wrote:
>>>
>>>
>>>> This is a good present idea for my mum or sister.
>>> Hi Toby.
>>>
>>>> How do you power it?
>>> I power mine from an old (ie redundant) laptop power supply to deliver
>>> ~ 19volts down a length of 10A two core cable. The sort used for hedge
>>> trimmers or lawn mowers. I use such a high voltage and thick cable to
>>> compensate for the voltage drop of the longish runs to the garden.
>>>
>>> At the camera end, this (highish) voltage is fed in to a buck dc-dc
>>> converter eg. https://tinyurl.com/vbbbv8f  This delivers a good steady
>>> supply of 5volts to the pi Zero W, camera and LEDs.
>>> ( nb. DO NOT USE A 7805 voltage regulator. It'll get way too hot! )
>>
>>
>> Cool, so do I have this right:
>> Connect the 19V across the inputs, then a large resistor across the
>> outputs, and use a multimeter to watch the voltage drop across the
>> large resistor while twisting the potentiometer with a screwdriver
>> until it matches 5V, then replace the resistor with the Raspberry Pi?
>>
> staggeringly bad way to do it
>
> read what he said.
> "this (highish) voltage is fed in to a buck dc-dc converter eg.
> https://tinyurl.com/vbbbv8f  This delivers a good steady supply of
> 5volts to the pi Zero W, camera and LEDs."

Or pick up one of the solid state DC-DC converters from eBay up to 22v
input, 5v and up to 3A out, e.g. https://www.ebay.co.uk/c/24003654862
You can get them with bare wires or pay a quid or two more to get one
with prefitted USB output sockets.

They seem to be designed for lads wanting to bling up their cars with
LEDs. I've been using one for two years now to run a Medion PNA in my
glider, powering it off the main 12v supply. Never any problems: it 'just
works'.

Pay a bit more and you can get a smaller, panel mount unit with two USB
sockets: in its flush face. Cut a hole in a panel to match the converter
diameter, drop it in and screw down the ring it comes with to mount it.


--
Martin    | martin at
Gregorie  | gregorie dot org

--- SoupGate-Win32 v1.05