×

Please see all COVID-19 updates here as some shipments may be delayed due to CDC safety and staffing guidelines. If you have an order or shipping question please refer to our Customer Support page. For technical questions please check out our Forums. Thank you for your continued support.

Bert Sierra

Member Since: February 7, 2015

Country: United States

  • Great article. I would think that a high-ampere solid state triac might be more suitable than a relay for this design. I would put in considerable overkill on the specs, given the spikes and surges that can come down AC lines. A 600V 25A triac will run about $5 from most vendors and would have plenty of headroom to control a 1500W oven. For the sake of safety, it might be wise to add an opto-isolator to control the triac’s gate, thus isolating the low voltage and AC sides completely. Best of all: triacs don’t tend to produce much heat, though you’d want to study the specs to make sure it could withstand heat produced within the oven.

    A simple design would simply switch the heating elements on or off as needed (triacs don’t actually turn off until the next zero crossing of the AC current occurs, so there’s a bit of delay). A more sophisticated design would analyze the AC voltage to allow the power to be turned on within each 50Hz / 60Hz cycle at a specific phase. By doing so, you could vary the power being delivered to the heating elements for more precise control of the oven’s temperature. [More power when heating up, less power to maintain a particular temperature, for example.]

    Just a thought. Relays to control that much current may not last as long as an equivalent triac, and a triac would occupy far less area on the circuit board.

  • No heatsink included? The SoC on the Raspberry Pi 3 runs considerably hotter than on RPi2 boards. I wouldn’t put it in a case without a nice heatsink, and furthermore a heatsink mounted with thermal adhesive and not merely double-sided tape.

No public wish lists :(