Hi pcmanbob,pcmanbob wrote: Hi.
You can't use a relay if you intend to use pwm control because a relay can't switch that fast.
You will need to design and build a transistor based power controller, or you could used a motor driver if you can find one designed to operated at 12V at around 5A or better.
If you can find a solid state relay that will switch DC voltage, most are DC control but only switch AC output.
So an L298N will only switch 2A max per output, so with 2 outputs that's 4A which is only 48W you were talking about 60W so you would need a bigger driver board.Regarding your suggestion to use a motor driver, I think it sounds pretty good! I was looking into this L298n motor driver https://www.conrad.com/p/joy-it-1573541. Considering that one Peltier will consume a max of 12V, and there are 2 available ports for Peltier, can I assume to give ~24 V external power source to the driver? I'm sorry if my questions are too ignorant for you, as I am just starting out with working on these things.
Works for me. No clearer information, though.
Code: Select all
S:\>wget http://www.grandado.com/products/collectie-1-st-nice-1-kanaals-ssr-solid-state-power-levert-hoge-lage-trigger-5a-12-v-relais-voor-arduino-uno-r3 --2019-04-29 20:01:20-- http://www.grandado.com/products/collectie-1-st-nice-1-kanaals-ssr-solid-state-power-levert-hoge-lage-trigger-5a-12-v-relais-voor-arduino-uno-r3 Resolving www.grandado.com... 188.8.131.52 Connecting to www.grandado.com|184.108.40.206|:80... connected. HTTP request sent, awaiting response... 301 Moved Permanently Location: https://www.grandado.com/products/collectie-1-st-nice-1-kanaals-ssr-solid-state-power-levert-hoge-lage-trigger-5a-12-v-relais-voor-arduino-uno-r3 [following] --2019-04-29 20:01:20-- https://www.grandado.com/products/collectie-1-st-nice-1-kanaals-ssr-solid-state-power-levert-hoge-lage-trigger-5a-12-v-relais-voor-arduino-uno-r3 Connecting to www.grandado.com|220.127.116.11|:443... connected. Unable to establish SSL connection.
Code: Select all
S:\>nslookup 18.104.22.168 22.214.171.124 Server: google-public-dns-a.google.com Address: 126.96.36.199 Name: shops.myshopify.com Address: 188.8.131.52
I also found a link to Aliexpress for the one with 4 channels https://www.aliexpress.com/store/produc ... Title=true. I'm not sure about the Russian part, as I was just directed to the Dutch website of Aliexpress.I Googled the item and the alternative seems to be aliexpress, defaulting to Russian!.
Isn't that what I actually show in the diagram?1st - your layout for that SSR device is incorrect. The 3 lug side is relay supply and control. The two lug side is normal open **switch**.
Is there any reason why this is the case? What other alternatives do you have in mind that I can use? The thing is the research I did point out that SSR is used for many PWM projects. It seems to work reasonably well with the high frequency of the PWM signal.Also, an SSR is not really a good choice for PWM.
Would you mind giving me direction on how to select the proper type of Peltier for heating purposes? Thank you! Sorry for my many questions!That model Peltier is not designed to be a heater.
As others have mentioned, if you only need to heat and not cool, then a peltier is an overly complicated way to do it. Just use heating elements instead. There are a bunch of ways to do it from (as mentioned above) nichrome wires (what you typically see in a kitchen toaster, power resistors, flat adhesive sticker type heaters, or heck, you could even use incandescent light bulbs to create heat if having the inside of the chamber lit up isn't an issue. Then you only need to monitor the temperature to regulate the heating elements.
Amazon and other online retailers of a similar nature are useless information resources.