{"product_id":"piezo-speaker-piezoelectric-sounder-contact-microphone-20mm-27mm-35mm","title":"Piezo Speaker Piezoelectric Sounder Contact Microphone 20mm, 27mm, 35mm","description":"\u003cp\u003eThis is one item of new piezoelectric speaker element available in a pack quantity of 1, 5, or 10 items. They have wires attached and are often used in equipment where there is a need for a simple beep sounder, often driven direct from a logic output. The maximum drive voltage is 30Vpp. The 20mm unit is approximately 0.4mm thick with the 27 and 35mm units being about 0.5mm, excluding the solder connections and wires. If you would like to mix sizes please select MIX option and let me know which you would like via a site message.\u003c\/p\u003e\n\u003cp\u003eHeadline Specs:\u003c\/p\u003e\n\u003cp\u003eDiameter(mm) Capacitance(nF) Resonant F (kHz)\u003c\/p\u003e\n\u003cp\u003e20 14 +\/-30% 6 +\/-0.5\u003cbr\u003e27 25 +\/-30% 4 +\/-0.5\u003cbr\u003e35 35 +\/-30% 3 +\/-0.5\u003c\/p\u003e\n\u003cp\u003eI've also used these as contact microphones attached to machinery, farm fences in windy conditions or long stretched wires which can result in some very interesting sound effects. For example a 10 metre long stretched copper wire when plucked produces something very similar to the old star trek \"phasers striking hull,\" noise, that being a similar method to how they created it in the first instance. The piezo part of the bare element will crack and degrade if bent, so the usual method is to attach the element to a piece of tin can first before attaching that to the vibration source. Two can be used at different spots on the wire for a stereo effect. The output can go directly into a standard low level microphone input socket on a tape recorder or computer sound card using screened cable.\u003c\/p\u003e\n\u003cp\u003eUsing the largest size as a speaker can be achieved by driving it backwards from a standard radio output through an LT700 audio matching transformer available on another listing. You need to glue or firmly attach it to a large cardboard box or something similar. Attaching it to something metal like a washing machine or disposable aluminium roasting tin creates a peculiarly metallic effect. You could use a second item as a microphone attached to the same metal piece for creating odd sound effects or a primitive plate reverb.\u003c\/p\u003e\n\u003cp\u003eAttaching them as microphones to a long stretched copper wire creates a great sound when the wire is plucked, similar to that heard on the original Star Trek series, \"phasers striking hull.\"\u003c\/p\u003e","brand":"HJW Electronics","offers":[{"title":"20mm \/ 1 Unit","offer_id":60000923910528,"sku":null,"price":1.8,"currency_code":"GBP","in_stock":true},{"title":"20mm \/ 5 Units","offer_id":60000923943296,"sku":null,"price":5.8,"currency_code":"GBP","in_stock":true},{"title":"20mm \/ 10 Units","offer_id":60000923976064,"sku":null,"price":9.8,"currency_code":"GBP","in_stock":true},{"title":"27mm \/ 1 Unit","offer_id":60000924008832,"sku":null,"price":1.8,"currency_code":"GBP","in_stock":true},{"title":"27mm \/ 5 Units","offer_id":60000924041600,"sku":null,"price":5.8,"currency_code":"GBP","in_stock":true},{"title":"27mm \/ 10 Units","offer_id":60000924074368,"sku":null,"price":5.8,"currency_code":"GBP","in_stock":true},{"title":"35mm \/ 1 Unit","offer_id":60000924107136,"sku":null,"price":1.8,"currency_code":"GBP","in_stock":true},{"title":"35mm \/ 5 Units","offer_id":60000924139904,"sku":null,"price":5.8,"currency_code":"GBP","in_stock":true},{"title":"35mm \/ 10 Units","offer_id":60000924172672,"sku":null,"price":9.8,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1007\/2136\/1280\/files\/piezo_group_s_a08f6ad5-84cc-4a62-b659-2520824f7039.jpg?v=1790702490","url":"https:\/\/shop.usefulcomponents.com\/products\/piezo-speaker-piezoelectric-sounder-contact-microphone-20mm-27mm-35mm","provider":"HJW Electronics","version":"1.0","type":"link"}