Electronic circuit for a dispenser

Thread Starter

DarrenGoh

Joined Oct 19, 2020
5
Hi, I would like to request help from anyone who can help.

I am currently doing a project which is creating a simple dispenser. This dispenser requires a programmable timer which when activated will cause a motor to rotate a piece of acrylic for about 0.75-1sec to release sand granules. The dispenser will be used outdoors, so if possible it must be battery powered instead of connecting it to a wall socket. I would like to ask how do I connect relays or a circuit to allow for a programmable timer to activate a motor for a short pulse.

Please help as I am currently stuck and clueless how to proceed.
 

Externet

Joined Nov 29, 2005
1,546
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Last edited:

AnalogKid

Joined Aug 1, 2013
8,705
1. Does the operate time have to be adjustable by the assembler / installer, or user-adjustable?

2. What initiates the action? Does the user press a button, does the unit automatically dispense sand every so often as long as it is turned on, or some other control process?

3. Are you looking for help with the timer, the relay / power connections, or both?

4. What are the power requirements for the motor? It is possible that it can be switched on and off with a solid state device instead of a relay. This almost certainly will take less power to do, saving battery life.

ak
 

Thread Starter

DarrenGoh

Joined Oct 19, 2020
5
How far have you got with this project? We can help you with problems but we are not a free design service.
Regards,
Keith
Currently I am at the designing of the electronic circuit phase, I looked at guides for many types of timer circuit but most of it doesn't fit my requirements. Thus I resort to this forum for help. I would like to ask for guidance on how to create a programmable timed circuit using relays and if possible only battery powered.
 

AnalogKid

Joined Aug 1, 2013
8,705
What is the adjustment range? With nothing but logic chips, a programmable timer could mean a lot of parts. LSI used to make programmable timer chips, but I don't know if they still are available. The smallest and cheapest approach is a microcontroller - ***IF*** you already have a software development system and a programmer.

How do you intend to "program" the timer? A knob with a calibrated dial? Keypad and digital display? Up/down buttons and an LED bar graph? iPhone app?

ak
 

Thread Starter

DarrenGoh

Joined Oct 19, 2020
5
1. Does the operate time have to be adjustable by the assembler / installer, or user-adjustable?

2. What initiates the action? Does the user press a button, does the unit automatically dispense sand every so often as long as it is turned on, or some other control process?

3. Are you looking for help with the timer, the relay / power connections, or both?

4. What are the power requirements for the motor? It is possible that it can be switched on and off with a solid state device instead of a relay. This almost certainly will take less power to do, saving battery life.

ak
1. It can be user-adjustable but it does not have to have a big range. Only dispense 1 day 1 time, or 2 days 1 time.

2. As long as it is turned on, or if there is power in the batteries. The dispenser will automatically dispense sand 1 time everyday or 1 time every 2 days.

3. I am looking for help with both.

4. I have no power requirement for the motor, I was intending to use a DC motor or a Servo motor.
 

Thread Starter

DarrenGoh

Joined Oct 19, 2020
5
What is the adjustment range? With nothing but logic chips, a programmable timer could mean a lot of parts. LSI used to make programmable timer chips, but I don't know if they still are available. The smallest and cheapest approach is a microcontroller - ***IF*** you already have a software development system and a programmer.

How do you intend to "program" the timer? A knob with a calibrated dial? Keypad and digital display? Up/down buttons and an LED bar graph? iPhone app?

ak
Hi AK,

The project just requires the device to be able to set the amount of time and the time to dispense the sand, similar to a pet food dispenser.

The programming of the timer can be just push buttons that sets two relay to activate the motor for 1sec. for example, Relay A (On) 10 sec, Relay B (Off) 11sec. The project requires it in terms of days. (1 day activate once)
 

AnalogKid

Joined Aug 1, 2013
8,705
For time-of-day programability, you now are programming three things: how long the motor runs, time of day, and every day or every other day. A pet food dispenser is a good analogy for what you are doing. For all of that you have to have a microcontroller; nothing else makes sense.

ak
 
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Thread Starter

DarrenGoh

Joined Oct 19, 2020
5
For time-or-day programability, you now are programming three things: how long the motor runs, time of day, and every day or every other day. A pet food dispenser is a good analogy for what you are doing. For all of that you have to have a microcontroller; nothing else makes sense.

ak
Okay, may I ask if there is any reference or example i can follow to create this circuit using a microcontroller? Thank you
 
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