Fish feeder

University of Victoria
Department of Electrical and Computer Engineering

ELEC 499A – DESIGN PROJECT









Automatic Fish Feeder – Final Report













Submitted by:

Patrick Audet paudet@uvic.ca
Tomas Martin tlcmo@uvic.ca

August 01, 2005


Submitted to: Amirali Baniasadi Ph. D. (Supervisor)

Table of Contents

1. EXECUTIVE SUMMARY 1

2.Introduction 2

3. Market analysis 3
3.1 Product Definition 3
3.2 Analysis of the pet products market 3
3.3 Competing products 4

4. Mechanical Design 5
4.1 Thermoelectric cooling devices – Seebeck effect 5
4.2 Thermoelectric cooling system design 6
4.3 TEC Calculations 8
4.4 TEC selection criteria 9
4.5 TEC cooling system design 11
4.6 Housing and feeding system12

5. Electrical Design 16
5.1 Component selection 16
5.1.1 LCD Display 16
5.1.2 Microcontroller 17
5.1.3 Stepper Motor 19
5.1.4 Motor Selection- Bipolar stacked (1 W/coil) 21
5.2 Power requirements 22
5.3 Microcontroller selection 22
5.4 Electrical schematics 24
5.5 Software 26
5.5.1 Main module: 26
5.5.2 Set module: 265.5.3 Motor movement: 27

6. Product costs 28
6.1 Bill of Materials 28
6.2 Total costs and expected selling price 29

7. Conclusions 30

8. Recommendations 30

9. References 31

List of Figures

FIGURE 1: HOUSEHOLD BREAKDOWN BY PET TYPE 3

Figure 2: Automatic feeder types and prices (5) 4

Figure 3: Seebeck Voltage diagram (7) 5

Figure 4: Thermocouples connectedin series (10) 6

Figure 5: Schematic of a thermocouple (9) 6

Figure 6: Parameters used in mathematical equations (12) 8

Figure 7: Performance of selected TEC (13) 9

Figure 8: Tellurex TEC dimensions (13) 10

Figure 9: Diagram of performance vs. Input power (8) 10

Figure 10: TEC Cooling Overview 11

Figure 11: Picture of TEC Assembly 11

Figure 12: Mechanical drawing 13Figure 13: Automatic fish feeder housing and heatsink assembly 14

Figure 14: Automatic fish feeder - fully assembled 15

Figure 15: Structure of a transmissive LCD display (16) 16

Figure 16: HD44780-based 2x16 character display 16

Figure 17: Unipolar motor structure (17) 19

Figure 18: Bipolar motor structure (17) 19

Figure 19: Bipolar motor structure (17) 20

Figure 20: Stackedstepper specifications (Danaher Motion) 21

Figure 21: BS2-SX Module schematic 23

Figure 22: Automatic fish feeder – electrical block diagram 24

Figure 23: Electrical Schematic 25

List of Tables

TABLE 1: TEC PARAMETER DEFINITIONS 8

Table 2: Microcontroller characteristics (all prices in US$) 18

Table 3: AFF Power requirements 22

Table 4: TEC Input/Output requirements 22

Table5: AFF Prototype – Material Costs 28



Executive Summary


Pet ownership has been increasing at a steady pace in the last 20 years. In the US, after dogs and cats, the most popular pet is now the freshwater fish.

More than 60% of households in the U.S. own a pet, and with pet ownership considered by many as an affordable luxury, it is not surprising to see that the total value ofthe pet industry approaching 35 Billion U.S. dollars (U.S. figures)

The Automatic fish feeder (AFF) is a product that focuses on this market. Its purpose is to dispense frozen fish food into an aquarium, automatically, and for up to 14 days.

This document provides a brief outlook on possibilities of the AFF in the market: It explores the total customer base, looks at competing products andthe preferred distribution channels or points of sale.

The mechanical design for a prototype unit, design and selection criteria for thermoelectric cooling, electrical component descriptions and complete electrical diagrams are also included in this document. The manufacturing cost is reviewed and compared to competitive products already on the market. Recommendations are made to improve the...