[chbot] Chchrobotics Digest, Vol 141, Issue 4

Wed Jun 26 09:15:14 BST 2019

The LEDs themselves should not be causing interference. What is probably
causing the interference is the buck mode converter which takes the higher
battery voltage and reduces it to the LED's voltage while increasing the
current, to achieve relatively high efficiencies. These use inductors and
rapidly switching transistors. If you can put up with higher battery
current drains and some localised heating, then you can use linear
regulators which don't have these switching elements and therefore don't
radiate.
Ferrite beads can be effective at keeping RF where it belongs - the tighter
around the wires and the longer the better. If you are prepared to solder
onto the circuit board, some strategically placed low value (100s of pF)
capacitors can help. (It helps to know the transmitter frequency to choose
the best values for the task.)
Not all LED lights even use regulators. Some of the cheaper ones with
multiple small LEDs just have a series resistor, and these should also be
quiet.
I hope this helps
Trevor

On Wed, Jun 26, 2019 at 10:43 AM Bevin Brett <bevin_brett at hotmail.com>
wrote:

> Talking to my daughter who is involved in kiwi conservation.  They track,
> find kiwi using small transmitters on the bird leg and the teams carry a
> directional receiver with About a one metre antenna
>
> But they can't use LED lights at night because of interference.
>
> How easy would it be to shield a normal commercial head lamp?
>
> Wrap it in alfoil?  Small metal mesh? Mesh with some trivial circuit?
>
> On Jun 17, 2019 11:00 PM, chchrobotics-request at lists.ourshack.com wrote:
>
> Send Chchrobotics mailing list submissions to
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> Today's Topics:
>
>    1. Sipeed MAix BiT for RISC-V AI+IoT - Seeed Studio (Synco Reynders)
>    2. Robotics Group meeting, Monday 17 June 2019, 630pm, 5 Idris
>       Road (Mark Atherton)
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 17 Jun 2019 21:58:00 +1200
> From: Synco Reynders <synco.reynders at gmail.com>
> To: Christchurch Robotics <chchrobotics at lists.linuxnut.co.nz>
> Subject: [chbot] Sipeed MAix BiT for RISC-V AI+IoT - Seeed Studio
> Message-ID:
> <CAKNOA8J=UrmPOjVwfwNP2rSkEMrbngRt-6-cTCTMUUuk098ogg at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Here is the link to where I bought the board...
>
> https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.seeedstudio.com%2FSipeed-MAix-BiT-for-RISC-V-AI-IoT-1-p-2873.html&data=02%7C01%7C%7C9de3110e1bff46b5abc008d6f312f8d3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636963660150070012&sdata=LhJuCO%2BfUC%2FicknxuIrv0qAXU8fsIgi8qLqWfAAKGqg%3D&reserved=0
>
> Data sheet for the K210
>
> https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.google.com%2Furl%3Fsa%3Dt%26source%3Dweb%26rct%3Dj%26url%3Dhttps%3A%2F%2Fs3.cn-north-1.amazonaws.com.cn%2Fdl.kendryte.com%2Fdocuments%2Fkendryte_datasheet_20181011163248_en.pdf%26ved%3D2ahUKEwiW-PPrjPDiAhW96nMBHRBbAecQFjABegQIBxAB%26usg%3DAOvVaw3CVZJWXlKkFgXPVCf8L4Ts%26cshid%3D1560765344956&data=02%7C01%7C%7C9de3110e1bff46b5abc008d6f312f8d3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636963660150070012&sdata=YtKt%2FRVCAZVXedlQd9dOBnCe13RRwBaBAQrCjHelSu8%3D&reserved=0
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> ------------------------------
>
> Message: 2
> Date: Mon, 17 Jun 2019 22:01:46 +1200
> From: Mark Atherton <markaren1 at xtra.co.nz>
> To: Christchurch Robotics <chchrobotics at lists.linuxnut.co.nz>
> Cc: Ian MacPherson <ian at macpherson.gen.nz>, Rory Deans
> <rory1 at xtra.co.nz>
> Subject: [chbot] Robotics Group meeting, Monday 17 June 2019, 630pm, 5
> Idris Road
> Message-ID: <6d4a8ac1-ad6c-fd28-1197-0fa30423c467 at xtra.co.nz>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> Hello everyone,
>
> Enthusiastic turnout with 20 attendees, and lots of huddles-of
> tech-talk. $28 + change (in gold, and flat-money) collected and
> transferred into the robotics loose-change jar (for later banking).
>
> Quick reminder: equipment donations are welcome for the trading table,
> but no products that are likely to be a disposal burden such as
> printers, toner or similar. All sales from the trading table should go
> into the brown box on the wall, and are directly for the benefit of our
> host club, NZART Branch 05.
>
> With thanks on behalf of the group,
>
> Mark Atherton
>
> ============
>
> Bevin brought along a soviet mechanical calculator to talk about as well
> as quite a photographic tour of one of his latest mechanical calculator
> repair projects. Challenges include trying to drift out a (possibly cold
> welded) taper pin. All in all, quite a mission…
>
> William brought in a homemade intercom using old telephones. Controller
> is based around an Arduino Nano. Nice recycling project.
>
> Peter Harris talked about switched mode power supplies, more
> specifically a battery management system for a home-made wall-of-power.
> Quite a discussion ensued around how to spread load across ten high
> voltage constant-current sources.
>
> Synco talked about a tiny 64 bit image recognition module. This US$21
> module includes VGA camera, a small LCD display and a CPU module. The
> main rub is that the CPU is RISC-V based running at 800MHz, with masses
> of I/O. The unit is configurable using a small FPGA, and is running a
> port of a micro-python wrapper controlling an embedded image-processing
> package.
>
> Andy Gardner talked about his +-100kV volt meter !
>
>
>
> ------------------------------
>
> Subject: Digest Footer
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> ------------------------------
>
> End of Chchrobotics Digest, Vol 141, Issue 4
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