[chbot] Chchrobotics Digest, Vol 141, Issue 4

Helmut Walle helmut.walle at gmail.com
Wed Jun 26 12:26:52 BST 2019


In addition to that, when using linear regulators with LEDs, regulate 
current rather than voltage. The reason for this is that these LEDs get 
quite hot during operation, and that probably lowers their threshold 
voltage noticeably, so that there may be a risk of thermal runaway.

Kind regards,

Helmut.

On 26/06/2019 8:15 PM, Trevor Wignall wrote:

> 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 
> <mailto: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
>     <mailto:chchrobotics-request at lists.ourshack.com> wrote:
>
>         Send Chchrobotics mailing list submissions to
>         chchrobotics at lists.ourshack.com
>         <mailto:chchrobotics at lists.ourshack.com>
>
>         To subscribe or unsubscribe via the World Wide Web, visit
>         https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.ourshack.com%2Fmailman%2Flistinfo%2Fchchrobotics&data=02%7C01%7C%7C9de3110e1bff46b5abc008d6f312f8d3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636963660150070012&sdata=r5wozd51OeHaPpYqcbXebThdQZGqZODeq7NvADHUvsQ%3D&reserved=0
>         or, via email, send a message with subject or body 'help' to
>         chchrobotics-request at lists.ourshack.com
>         <mailto:chchrobotics-request at lists.ourshack.com>
>
>         You can reach the person managing the list at
>         chchrobotics-owner at lists.ourshack.com
>         <mailto:chchrobotics-owner at lists.ourshack.com>
>
>         When replying, please edit your Subject line so it is more
>         specific
>         than "Re: Contents of Chchrobotics digest..."
>
>         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
>         <mailto:synco.reynders at gmail.com>>
>         To: Christchurch Robotics <chchrobotics at lists.linuxnut.co.nz
>         <mailto: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
>         <mailto: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
>         -------------- next part --------------
>         An HTML attachment was scrubbed...
>         URL:
>         <https://eur04.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.ourshack.com%2Fpipermail%2Fchchrobotics%2Fattachments%2F20190617%2Fe1b88019%2Fattachment-0001.html&data=02%7C01%7C%7C9de3110e1bff46b5abc008d6f312f8d3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636963660150070012&sdata=OHsdiV3W65D6hEbkciVDIt8pIsWL4Zkg1Ik%2F%2FZ7s8p0%3D&reserved=0>
>
>         ------------------------------
>
>         Message: 2
>         Date: Mon, 17 Jun 2019 22:01:46 +1200
>         From: Mark Atherton <markaren1 at xtra.co.nz
>         <mailto:markaren1 at xtra.co.nz>>
>         To: Christchurch Robotics <chchrobotics at lists.linuxnut.co.nz
>         <mailto:chchrobotics at lists.linuxnut.co.nz>>
>         Cc: Ian MacPherson <ian at macpherson.gen.nz
>         <mailto:ian at macpherson.gen.nz>>, Rory Deans
>         <rory1 at xtra.co.nz <mailto: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
>         <mailto: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
>
>         _______________________________________________
>         Chchrobotics mailing list
>         Chchrobotics at lists.ourshack.com
>         <mailto:Chchrobotics at lists.ourshack.com>
>         https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.ourshack.com%2Fmailman%2Flistinfo%2Fchchrobotics&data=02%7C01%7C%7C9de3110e1bff46b5abc008d6f312f8d3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636963660150070012&sdata=r5wozd51OeHaPpYqcbXebThdQZGqZODeq7NvADHUvsQ%3D&reserved=0
>         Mail Archives:
>         https://eur04.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.ourshack.com%2Fpipermail%2Fchchrobotics%2F&data=02%7C01%7C%7C9de3110e1bff46b5abc008d6f312f8d3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636963660150070012&sdata=Z1Ob44RcnVoYuJKo6q8HK7eDazZIu8FMyWtp7R2A2ks%3D&reserved=0
>         Meetings usually 3rd Monday each month. See
>         https://eur04.safelinks.protection.outlook.com/?url=http%3A%2F%2Fkiwibots.org&data=02%7C01%7C%7C9de3110e1bff46b5abc008d6f312f8d3%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636963660150070012&sdata=Bg2lYcFqAA%2F5JrV6Cmwih2gwTM7G5c%2BbWGJ%2FayDtDzU%3D&reserved=0
>         for venue, directions and dates.
>         Please edit your Subject line to reflect new subjects.
>
>         ------------------------------
>
>         End of Chchrobotics Digest, Vol 141, Issue 4
>         ********************************************
>
>
>     _______________________________________________
>     Chchrobotics mailing list Chchrobotics at lists.ourshack.com
>     <mailto:Chchrobotics at lists.ourshack.com>
>     https://lists.ourshack.com/mailman/listinfo/chchrobotics
>     Mail Archives: http://lists.ourshack.com/pipermail/chchrobotics/
>     Meetings usually 3rd Monday each month. See http://kiwibots.org
>     for venue, directions and dates.
>     When replying, please edit your Subject line to reflect new subjects.
>
>
> _______________________________________________
> Chchrobotics mailing list Chchrobotics at lists.ourshack.com
> https://lists.ourshack.com/mailman/listinfo/chchrobotics
> Mail Archives: http://lists.ourshack.com/pipermail/chchrobotics/
> Meetings usually 3rd Monday each month. See http://kiwibots.org for venue, directions and dates.
> When replying, please edit your Subject line to reflect new subjects.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ourshack.com/pipermail/chchrobotics/attachments/20190626/af4c1c17/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Helmut_Walle.vcf
Type: text/x-vcard
Size: 149 bytes
Desc: not available
URL: <http://lists.ourshack.com/pipermail/chchrobotics/attachments/20190626/af4c1c17/attachment-0001.vcf>


More information about the Chchrobotics mailing list