EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: dazz1 on August 25, 2018, 09:26:36 pm
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Hi
I have built a hot wire plastic bending machine. I need an adjustable timer to control the two power supplies (one for the top wire, one for the bottom wire).
I need a digital timer to control how long power is applied to the heating wires. I have access to the low voltage/current reference on the power supply voltage adjustment pot.
The specifications for the timer are:
Interval range: 1 to 60 seconds
Resolution: 1 second
Adjustment: rotary encoder
Input supply: 24VDC ideal but could be 12-48VDC
Display: LED or LCD
The specs are undemanding but I can't find a suitable timer.
The key requirement is the rotary (encoder?) adjustment. I need to be able to easily tweak the interval and a keypad or decade switches are too annoying.
Also I want something off-the-shelf. A finished product or a kit. I do not want to be making PCBs or cutting code.
Any suggestions??
Dazz
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Well there are modules like the one linked below but you'll need to run them off a 12V regulator, remove the potentiometer and replace it with a panel mounted one. The trouble is there's no numerical display and the delay is continuously variable, rather than discrete steps.
https://www.ebay.co.uk/itm/0-60-Second-Delay-Time-Switch-1-Minute-Adjustable-DC12v-NE555-Timer-Relay-Module-/252337831522 (https://www.ebay.co.uk/itm/0-60-Second-Delay-Time-Switch-1-Minute-Adjustable-DC12v-NE555-Timer-Relay-Module-/252337831522)
It seems you want something more elaborate, such as using a knob to dial in a delay, which is displayed on a display, so I doubt you'll be able to find anything off the shelf. If you don't have the skills or time to design and build your own, then your only option is to employ someone to do it for you, but that won't be cheap.
What's your budget?
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Hi
I'm a professional electronics Engineer so designing/making something like this timer is not a challenge. The application is work related, not hobby so my time is too expensive for a one-off like this.
I am looking for an off-the-shelf solution for a rather general problem.
At present I have $5 Chinese Onbon timer relay clones with push-button decade switches. They do the job but are annoying to adjust.
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Hi
I found this design here:
https://arduinoplusplus.wordpress.com/2016/02/27/led-display-relay-timer/ (https://arduinoplusplus.wordpress.com/2016/02/27/led-display-relay-timer/)
Dazz
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There are a ton of small relay/timer modules like these on Aliexpress/eBay: (this one is 16V)
https://www.aliexpress.com/item/DC-12V-LED-Digital-display-Home-Automation-Delay-Relay-Trigger-Time-Circuit-Timer-Control-Cycle-Adjustable/32835247322.html?spm=2114.10010108.1000014.2.56366cc96wpWhC&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.13338.115306.0&scm_id=1007.13338.115306.0&scm-url=1007.13338.115306.0&pvid=359a1c66-5453-4f6e-97c0-b1678a16bf00 (https://www.aliexpress.com/item/DC-12V-LED-Digital-display-Home-Automation-Delay-Relay-Trigger-Time-Circuit-Timer-Control-Cycle-Adjustable/32835247322.html?spm=2114.10010108.1000014.2.56366cc96wpWhC&gps-id=pcDetailBottomMoreOtherSeller&scm=1007.13338.115306.0&scm_id=1007.13338.115306.0&scm-url=1007.13338.115306.0&pvid=359a1c66-5453-4f6e-97c0-b1678a16bf00)
This one for example is in 5V, but has buttons for setting the delay. That's something that could be hooked up to a rotary encoder quite easily.
https://www.aliexpress.com/item/6-30V-Relay-Module-Switch-Trigger-Time-Delay-Circuit-Timer-Cycle-Adjustable-828-Promotion/32827374496.html?spm=2114.10010108.addToCart.3.16d06acf3PufDK&gps-id=pcDetailCartBuyAlsoBuy&scm=1007.12908.99722.0&scm_id=1007.12908.99722.0&scm-url=1007.12908.99722.0&pvid=6cfe769b-0239-43be-801d-e5a14660f855 (https://www.aliexpress.com/item/6-30V-Relay-Module-Switch-Trigger-Time-Delay-Circuit-Timer-Cycle-Adjustable-828-Promotion/32827374496.html?spm=2114.10010108.addToCart.3.16d06acf3PufDK&gps-id=pcDetailCartBuyAlsoBuy&scm=1007.12908.99722.0&scm_id=1007.12908.99722.0&scm-url=1007.12908.99722.0&pvid=6cfe769b-0239-43be-801d-e5a14660f855)
Bonus question: where is the MCU?? :-//
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There are a ton of small relay/timer modules like these on Aliexpress/eBay
Bonus question: where is the MCU?? :-//
Thanks for taking the time to research this problem. I buy a lot of stuff from Aliexpress and I did do a lot of research trying to identify a good off the shelf product but I could not find anything that matched all of my requirements.
I haven't figured out exactly where I will mount the MCU yet. I still need to start and finish the coding development.
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So I take it you ended up designing it yourself? That's often the best way, even though it may be the most expensive.
What microcontroller did you go for? Did you opt for an encoder or potentiometer?
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So I take it you ended up designing it yourself? That's often the best way, even though it may be the most expensive.
What microcontroller did you go for? Did you opt for an encoder or potentiometer?
Hi
Yes I am going to write custom code. I couldn't help myself. Nothing off the shelf does quite what I want.
I will be using an encoder plus some momentary push button switches. The additional switches will avoid complicated command sequencing/coding of the encoder momentary switch.
I am not at home to look, but I am using a mini or micro something arduino controller.