{"id":5157,"date":"2021-07-18T02:34:56","date_gmt":"2021-07-18T02:34:56","guid":{"rendered":"https:\/\/pariswells.com\/blog\/?p=5157"},"modified":"2021-07-18T02:34:56","modified_gmt":"2021-07-18T02:34:56","slug":"raspberry-pi-how-to-get-gpio-outputs-for-reed-relay-hall-effect","status":"publish","type":"post","link":"https:\/\/pariswells.com\/blog\/research\/raspberry-pi-how-to-get-gpio-outputs-for-reed-relay-hall-effect","title":{"rendered":"Raspberry Pi – How to get GPIO Outputs for Reed Relay \\ Hall Effect"},"content":{"rendered":"

Recently received my first Raspberry Pie and needed to get input sensors, especially a reed switch and also testing a Hall Effect Sensor<\/p>

Reed Switch with Hardware Pull Down ( Resistors )\u00a0<\/strong><\/p>

\"What<\/p>

On the Pie this looks like<\/p>

 <\/p>

\"How<\/p>

Reed Switch with Internal Pull Down Resistor\u00a0<\/strong><\/p>

see below , gpios 0-8 are pulled high, the rest are pulled low. They are all inputs. Those initial power on states can not be changed – it’s wired into the SoC. So if you are wanting to use below make sure you use GPIO over 8 so it can withstand a reboot<\/p>

\"\"<\/p>

Hall Effect Sensor with Hardware Pull Down ( Resistors )\u00a0<\/strong><\/p>

This has three pins ( Extra Digital Out )\u00a0 so needs to be Wired differently , we just need to protect the GPIO Pins<\/p>

 <\/p>

\"\"<\/p>

 <\/p>

\"\"<\/p>

I used GPIO’s 4,5,6<\/p>

#enables GPIO 4
echo 4 > \/sys\/class\/gpio\/export

#marks 4 as input ( not Output )
sudo echo in > \/sys\/class\/gpio\/gpio4\/direction

#Configure the gpios to trigger an interrupt on both edge ( An edge is the name of a transition from HIGH to LOW (falling edge<\/em>) ) – LOW to HIGH (rising edge)<\/a>.
echo both > \/sys\/class\/gpio\/gpio4\/edge<\/p>

#ActiveType<\/a><\/code>\u00a0constant to select active high, which means that logical\u00a0true<\/code> corresponds with high voltage. \u00a0active low, which means that logical\u00a0true<\/code> corresponds with low voltage. \u00a00 (false) or 1 (true)<\/p>

echo 0 > \/sys\/class\/gpio\/gpio4\/active_low<\/p>

How to read the current value of GPIO<\/strong><\/p>

cat \/sys\/class\/gpio\/gpio4\/value<\/p>

raspi-gpio get 4<\/p>

How to set GPIO Pull Down\u00a0<\/strong><\/p>

On Boot gpios 0-8 are pulled high, the rest are pulled low. They are all inputs. Those initial power on states can not be changed – it’s wired into the SoC<\/p>

raspi-gpio set 4 pd<\/p>

pu set GPIO in-pad pull up
pd set GPIO pin-pad pull down<\/p>

 <\/p>

 <\/p>

 <\/p>

\u00a0<\/pre>","protected":false},"excerpt":{"rendered":"
Recently received my first Raspberry Pie and needed to get input sensors, especially a reed switch and also testing a Hall Effect SensorReed Switch with Hardware Pull […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[3542,3541,3538,3540,3544,3543,3545,3539],"class_list":["post-5157","post","type-post","status-publish","format-standard","hentry","category-research","tag-bread-board","tag-edges","tag-gpio","tag-hall-effect","tag-pull-down","tag-pull-up","tag-rapsberry-pi","tag-reed-switch"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/posts\/5157","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/comments?post=5157"}],"version-history":[{"count":5,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/posts\/5157\/revisions"}],"predecessor-version":[{"id":5209,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/posts\/5157\/revisions\/5209"}],"wp:attachment":[{"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/media?parent=5157"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/categories?post=5157"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pariswells.com\/blog\/wp-json\/wp\/v2\/tags?post=5157"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}